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Jul 19, 2016 - Although individual and group cognitive-behavioral therapy (CBT) is the standard ... A structured support group led by trained facilitators.
Contemporary Clinical Trials 50 (2016) 98–105

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Contemporary Clinical Trials journal homepage: www.elsevier.com/locate/conclintrial

Comparison of a peer facilitated support group to cognitive behavior therapy: Study protocol for a randomized controlled trial for hoarding disorder Soo Y. Uhm PhD a, Janice Y. Tsoh PhD a, R. Scott Mackin PhD a, Michael Gause MA b, Joanne Chan PsyD b, John Franklin MA b, Monika Eckfield PhD, RN c, Mark Salazar b, Ofilio Vigil MA e, David Bain MS b, Sandra Stark b, Eduardo Vega MA b, Kevin L. Delucchi PhD a, Carol A. Mathews MD a,d,⁎ a

Department of Psychiatry, University of California, San Francisco, California, USA Mental Health Association of San Francisco, San Francisco, California, USA c Department of Nursing and Health Sciences, California State University, East Bay, California, USA d College of Medicine, University of Florida, Florida, USA e University of California Davis Health System, California, USA b

a r t i c l e

i n f o

Article history: Received 28 February 2016 Received in revised form 14 July 2016 Accepted 17 July 2016 Available online 19 July 2016 Keywords: Cognitive behavioral therapy Comparative effectiveness trial Community partnership Hoarding

a b s t r a c t Although individual and group cognitive-behavioral therapy (CBT) is the standard treatment approach for hoarding disorder (HD), it requires trained mental health professionals with specialization in HD. There is a need to offer additional options and services due to the limited number of professionals with advanced training, combined with the high prevalence rate of individuals with HD. A structured support group led by trained facilitators or lay professionals using a facilitator's manual and participant workbook (Buried in Treasures or BiT), addresses this need and increases accessibility. Prior studies of BiT groups have shown decreased hoarding symptoms. Only one retrospective study compared BiT and CBT outcomes in a naturalistic setting and showed no difference. Thus, a well-powered randomized controlled trial is needed to directly compare these forms of treatment. This paper presents a non-inferiority controlled trial protocol that compares group CBT to group BiT. Three hundred participants with HD, 18 years or older, are being recruited for a 16-week treatment study. Participants are randomly assigned to either the CBT or BiT group. The primary outcome is reduction in hoarding symptom severity. Secondary outcomes include reduction in other indices of hoarding symptomology, including functional impairment, physical clutter, cognition, and changes in neuropsychological functioning. © 2016 Elsevier Inc. All rights reserved.

1. Introduction In 2013, Hoarding Disorder (HD) was formally recognized as a distinct mental illness in the DSM-5[1]. HD is defined as persistent difficulty and/or distress in discarding possessions, resulting in accumulation that prevents the use of living spaces and impairment in social, occupational, or other areas of functioning. Although under-recognized, HD has a profound impact on individuals' functioning and quality of life. At 2– 5% [2,3], HD has a lifetime prevalence rate that is comparable to or higher than those of more commonly known disorders (1% for Autism, 2% for Obsessive Compulsive Disorder, 4% for Bipolar) [4,5]. Rates increase substantially over age 55, to 6.2% [6–9]. However, despite these rates, research and consequently our understanding of HD lags behind other disorders. The standard of care for treatment of HD is individual or group cognitive-behavioral therapy (CBT) [10], performed by licensed mental ⁎ Corresponding author at: 100 S Newell Dr, Gainesville, Florida 32611, USA. E-mail address: carolmathews@ufl.edu (C.A. Mathews).

http://dx.doi.org/10.1016/j.cct.2016.07.018 1551-7144/© 2016 Elsevier Inc. All rights reserved.

health providers, using a HD-specific CBT treatment manual and facilitators' guide [11,12]. However, due to the limited number of providers who specialize in the treatment of HD, increased access to care for this underserved population is needed. One strategy is to disseminate evidence-based HD treatments that can be delivered by non-mental health professionals in group settings. Hence, a self-help workbook called Buried in Treasures (BiT) [13], and an associated peer facilitators' guide [14], were developed for people with HD that can be delivered by lay or peer professionals in group settings. A recent study suggests that group CBT and group BiT have similar improvement rates in hoarding symptoms [15]. Though these initial results are promising, there have only been two studies conducted using the BiT protocol [15,16], and the existing CBT studies vary in structure (e.g., home visit and session length variation), and type of comparison group [10]. There is a need to directly compare group CBT and BiT in a randomized trial of a large cohort of participants, using a protocol that would be feasible and sustainable in community settings (i.e., real-world conditions). Moreover, individuals with HD often express distress regarding memory loss, difficulties with attention, and other executive dysfunctions. In a

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recent study, participants with HD showed impairment in some neurocognitive domains (e.g. categorization and verbal learning) but improvement in others (e.g., abstract reasoning) [17]. Given the association of specific cognitive impairments with HD and patient perceived cognitive dysfunction, there is a need to further evaluate neurocognitive functioning in treatment outcome—both whether neurocognitive functioning predicts treatment outcome, and whether participation in treatment is associated with improvement in specific aspects of cognitive functioning. This study's objective is to compare the efficacy of manualized BiT and CBT group treatment for HD using a randomized controlled noninferiority trial design. We hypothesize that CBT and BiT are equally effective in improving symptoms of HD. In addition, this study will examine predictors of treatment outcome across both conditions, and examine the relationship and impact of cognitive function and other individual characteristics on treatment outcome. This paper provides a detailed methodological description of this randomized clinical trial, which can serve as a model for other investigators designing HD treatment trials.

2. Methodology 2.1. Overview This trial compares the current standard of care for group treatment of HD (CBT) to an innovative and promising community-based group treatment (BiT). After screening and pre-treatment assessments confirm the diagnosis of HD, 300 participants will be stratified by gender and geographic location and randomized to either CBT or BiT. Participants in both treatment arms receive one 2-h session of group therapy weekly with CBT participants receiving 16 sessions and BiT participants 15 sessions. The study was approved by the Institutional Review Board of the University of California, San Francisco.

2.2. Collaborative partners and project team organization The project is a partnership between the Mental Health Association of San Francisco (MHASF) and the University of California, San Francisco (UCSF). The Principal Investigator (PI) of the Project, a psychiatrist at UCSF, directs the overall operations and scientific conduct of the project. The partnership operations have two arms: 1) patient advocacy; and 2) research. The patient advocacy arm, led by the MHASF team, is primarily responsible for recruiting and screening participants, securing group treatment sites, training BiT group leaders and leading BiT groups. The MHASF team includes members of the administrative staff with expertise in hoarding related programs, including those who oversee the annual hoarding related conference held by MHASF. In addition, the team includes a research coordinator, peer-facilitators who are trained to deliver BiT and are individuals from the community with lived hoarding experience, and supervisors for the peer facilitators who are community clinicians and/or individuals with lived hoarding experience and prior group facilitation experience. Lastly, a consultant who is the developer of the BiT facilitators' manual provides consultation on BiT implementation. The research arm is led by the UCSF team with a primary responsibility for clinical and neuropsychological assessments, training and supervising CBT group leaders, conducting CBT groups, data management, and analyses. The UCSF team consist of a psychiatrist (the PI) with clinical and research expertise in HD, a biostatistician with expertise in clinical trials design, a neuropsychologist with expertise in neurocognitive assessment of individuals with HD, a research coordinator, and postdoctoral psychology fellows who are trained to deliver CBT following the HD-specific CBT manual. Thus, the collaborative relationship between the investigators at UCSF and those at MHASF complements each other's unique specialties and strengths.

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2.3. Recruitment Individuals with HD are being recruited through media advertisements (radio, internet), advertisements on the MHASF website and on hoarders.org, emails sent to treatment providers, the MHASF listserv and the International Obsessive Compulsive Disorder Foundation (IOCDF) local support group chapter's listserv. Peer facilitators speak at organizations and at outreach events as “peers” who share their lived experience with our target population. Flyers are distributed at coffee shops, laundromats, libraries, and community centers. Furthermore, announcements are made at ongoing drop-in support groups for HD conducted by the MHASF, and at the annual conference on Hoarding and Cluttering, which is attended by individuals with HD, their family members, treatment providers, and other key stakeholders. The study has also been registered with clinicaltrials.gov (NCT02040805). 2.4. Eligibility criteria 2.4.1. Screening and inclusion criteria Individuals are screened if they are 18 years of age or older, reside in the greater Bay Area community, are identified by mental health professionals as having hoarding behaviors, and are interested in treatment for hoarding. Interested people contact MHASF staff (i.e., peer facilitators or recruitment coordinator) by telephone or in person. They then conduct an initial screening to ensure that potential participants have primary hoarding behaviors (difficulty discarding, excessive acquiring) rather than difficulties primarily arising from problems with organization or physical or mental health limitations (such as depression) that lead to passive clutter rather than specific difficulties with discarding objects. They explain the nature of the study, including randomization, monetary compensation, and group treatment information to potential participants. At that time, verbal consent to participate is obtained. Individuals who meet the self-reported hoarding problems and treatment criteria complete three screening questionnaires: the Savings Inventory-Revised (SI-R), the UCLA Hoarding Symptom Scale (UHSS), and the Clutter Image Rating Scale (CI-R) (see descriptions below). These measures are commonly used to assess HD related behaviors and cognitions. Individuals who meet the cutoff scores for clinically significant hoarding on two of the three measures (SI-R≥42, UHSS≥20, CIR≥12) are then contacted by UCSF staff for the final screening in-person interview with UCSF staff to confirm a diagnosis of HD using the Structured Instrument for Hoarding Disorder (SIHD) [18]. As has been done in previous studies [17,19], the screening criteria were chosen to rule out participants who live in a hoarding environment (e.g., family members who hoard), but who would not themselves meet the criteria for HD. 2.4.2. Exclusion criteria Individuals with dementia are excluded due to an associated high rate of collecting or hoarding behaviors that differ phenotypically and etiologically from HD. Individuals with current or past psychiatric comorbidities or symptoms are not excluded unless they are disruptive and cannot be redirected during in-person UCSF evaluations or during group treatment. Individuals who have participated in either CBT for hoarding (group or individual) or in group BiT in the past year are excluded from participation. We chose this time frame for exclusion based on prior treatment because we anticipated, from clinical experience, that the gains received from HD specific prior treatment would be stable after a year, and that individuals who met the severity criteria for entry into the study at the time of assessment would stand to benefit. Individuals who receive (d) non-CBT forms of treatment for HD or CBT treatments for non-hoarding disorders are not excluded from the study. This includes participation in support groups such as Clutterers Anonymous or the receipt of individual therapy for other problems (e.g., PTSD, depression). Similarly, medication treatment for HD is not an exclusion criterion.

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2.5. Consent The in-person evaluation interview with UCSF staff is conducted for individuals who meet the initial screening criteria. UCSF staff provides a more thorough explanation of all of the components of the study, provides opportunities for individuals to ask questions related to the study and confirm their interest in participation, and obtains a written informed consent. Participants consent to completing self-report measures of hoarding and associated symptoms prior to treatment, participating in a clinical interview to assess psychiatric symptoms, neuropsychological testing at pre and post-treatment, and completing regular self-report questionnaires during treatment. They receive compensation for the time that they spend in the pre and post assessments ($30 for pre-treatment, $70 for post-treatment), and parking validation. They are not compensated for their participation in the treatment groups, which is explained in the consent process. Individuals who passed the initial screening but do not meet the formal inclusion criteria after the clinical interview are directed to our community partner, MHASF for other ongoing hoarding related services, including a drop in support group. See Table 1 for timing and mode of administration of all assessment schedules. 2.6. Randomization and blinding Consented individuals (hereafter referred to as “participants”) who meet all of the inclusion and none of the exclusion criteria are randomized to either CBT or BiT with stratification by gender in a 1:1 ratio to insure equal balance between the conditions for men and women. Participants are also stratified by geographic location, as the treatment groups take place in three cities in the Bay Area (San Francisco, Berkeley, and San Mateo). To date, neurocognitive functioning has not yet been clearly associated with HD treatment outcomes. Therefore, it is not included in the randomization. Neither treatment providers nor participants are blinded to treatment condition, but treatment providers and the research team are blinded to the neurocognitive status, and other relevant individual characteristics of participants. Individuals conducting the analyses comparing group outcomes are blinded to group status (groups are coded as “A” and “B” prior to analysis to ensure this blind). 2.7. Treatment After randomization, participants receive either CBT or BiT treatment. Each treatment group has 8–12 participants, the standard size of the groups run by the MHASF. The range of the group size was also chosen to account for expected attrition with the groups, to maximize the number of individuals treated in the time period. CBT and BiT groups

are run concurrently at each of the sites in locations that are easily accessible by public transportation. The majority of the treatment groups are held at non-profit community centers such as consumer-run mental health agencies and senior centers, although one of the sites is based at an academic research clinic. Both evening and daytime groups are offered. Thus, at any given time, approximately six to eight groups (3–4 CBT and 3–4 BiT) will occur per week in the Bay Area during the active treatment component of the study. The CBT and the BiT treatment groups are similar in structure and topics covered, and both use a manualized CBT-based protocol (Table 2). Treatments are similar in session length (two hours each) and in duration. The treatment duration of the CBT groups is 16 sessions with 4 weeks of break within the treatment. The treatment duration of the BiT groups is 15 sessions with 5 weeks of break within the treatment. Therefore, the 16 CBT sessions will be delivered over 20 weeks and the 15 BiT sessions will also be delivered over 20 weeks. Participants who miss N 3 sessions will be dropped from the treatment study. Individuals who have participated in more than three sessions of CBT or BiT for HD through this research protocol are not eligible for re-entry into the study. One to two facilitators will lead the groups in both treatment arms. The protocol was designed to be flexible in order to maximize the generalizability to the community (where only one facilitator may be available at times). Attendance and homework completion will be assessed at every session for both treatment groups. Adverse events will also be assessed as a part of the weekly check in process in the groups. Events that may compromise the individual's treatment or health, such as increasing suicidal ideation, active drug use during group sessions, and conflict between participants will be noted and followed by the facilitators for signs of escalation. Participant safety and ability to continue in group will be assessed by the facilitator(s) and by the PI of the study in the event of an adverse event. All adverse events will be reported to the UCSF Institutional Review Board and to the study's Data Safety Monitoring Board.

Table 2 CBT and BiT treatment session topics and duration. Week⁎ CBT session topics

BiT session topics

1 2

1. Getting to know each other 2. Meet the bad guys

3 4 5 6 7 8

Table 1 Assessment schedule. Assessment

Time points

Mode of administration

UHSS SI-R CI-R ADL-H SIHD MINI BDI BAI NA BA TA

Screening Screening, post-treatment Screening, pre and post-treatment Pre-and post-treatment Pre-treatment Pre-treatment Pre-and post-treatment Pre-and post-treatment Pre-and post-treatment Pre-and post-treatment Weekly during treatment (7–8 times)

Research assistant Self-report Clinician Self-report Clinician Clinician Self-report Self-report Research assistant Self-report Self-report

Note. UHSS, UCLA Hoarding Severity Scale; SI-R, Saving Inventory-Revised; CI-R, Clutter Image Rating Scale; SCI-R, Savings Cognition Inventory, Revised; ADL-H, Activities of Daily Living Scale in Hoarding Disorder; SIHD, Structured Interview for Hoarding Disorder; MINI, Mini International Neuropsychiatric Interview; BDI, Beck Depression Inventory-II; BAI, Beck Anxiety Inventory; NA, Neuropsychological assessment; BA, Beliefs assessment; TA, Treatment assessment.

9 10 11 12 13 14 15 16 17 18 19 20

1. Introduction and model-building 2. Continue model-building, motivation 3. Goals, treatment planning Break 4. Reducing acquisition 5. Exposure practice 6. Decisions about saving and discarding 7. Skills training for organization Break 8. Clutter buddies: instructions for coaches and clutter buddies 9. Exposure practice for letting go 10. Cognitive strategies and cognitive therapy skills for letting go Break

3. Here come the good guys! 4. How did this happen? 5. Enhancing motivation 6. Help with reducing acquiring 7. More help with reducing acquiring 8. Sorting and discarding: getting ready Break 9. Sorting and discarding: let's go!

10. Working with clutter buddies 11. Sorting and discarding: practicing letting-go 12. Sorting and discarding: succeeding! 11. Non-acquisition practice 13. Here come the bad guys again 12. Barriers to progress Break 13. Maintaining systems and gains Break 14. Review of treatment methods 14. Taking on your brain 15. Review of progress and next steps Break Break Break 16. Termination, self-report 15. Graduation, self-report questionnaires, and celebration questionnaires, and celebration

Note: CBT, Cognitive Behavioral Therapy; BiT, Buried in Treasures. ⁎ Week represents treatment week; a total of 20-week treatment duration including 4 breaks for CBT and 5 breaks for BiT. The table above shows an example of a sample treatment schedule for each group. Breaks may vary due to facility and holiday schedules.

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The key differences between the two treatment arms are: 1) a trained doctoral level mental health provider delivers CBT as compared to trained peer facilitator for BiT, 2) a structured and formal atmosphere in the CBT group compared to a less structured atmosphere in the BiT group, 3) use of a simplified CBT approach in the BiT arm that focuses on practical applications and facilitators' guide written in lay language that is more accessible to peer facilitators and participants, 4) assignment of clutter buddies from within the groups by the CBT facilitators, vs. encouragement (but not assignment) of clutter buddies by the BiT facilitators, 5) two home visits each for the CBT participants vs. no home visits for the BiT participants, 6) weekly telephone check-ins between sessions by the BiT facilitators vs. no initiated between-session contact by the CBT facilitators except for home visits or safety concerns, and 7) arriving N15 min late or leaving N 15 min early to group considered an absence in the CBT group vs. encouragement to be timely for the BiT group. The details of each group treatment are described below. 2.8. CBT group treatment 2.8.1. Procedures CBT group participants receive 16 sessions of group therapy over 20 weeks (4 weeks of break within the treatment, see Table 2), based on a structured manual adapted from the individual CBT workbook for hoarding by Steketee and Frost (2006). The manual was also adapted to include the assignment of clutter buddies (from within the group), based on our previous experience in the MHASF-run CBT groups; individuals with HD who attended the groups were typically isolated and had difficulty identifying clutter buddies on their own. Although this discussion was noted on the BiT side, the peer facilitators chose not to assign clutter buddies from within the group, consistent with the peer approach. Additionally, the manual was adapted to change the first home visit from pre-treatment to after the third session of treatment to decrease fears of stigma and judgment. CBT groups are facilitated by one to two trained clinical postdoctoral psychology fellows who receive weekly supervision from a clinical psychologist and/or psychiatrist with HD specialization to monitor treatment administration and risk management of participants. To ensure consistency and fidelity of treatment administration, the supervising psychologist directly observes each CBT group facilitator in conducting their first session, and at least two more times throughout the course of the study. 2.8.2. Delivery Each 2-h session consists of weekly check-ins and psychoeducation about hoarding to accomplish the following objectives: developing an understanding and awareness of one's hoarding symptoms and patterns, behavior modification, cognitive restructuring, goal-setting, motivational enhancement, in vivo and imagery exposure for discarding and acquisition, executive skills training (such as organization, sorting, planning, decision-making, and problem-solving), establishing “clutter buddies”, and relapse prevention. Treatment topics, shown in Table 2, and length of each group session, can be adjusted according to group dynamics and readiness. In each session, participants receive homework assignments, which include reading, exercises to engage participants in applying skills learned during sessions, and personal decluttering using CBT techniques. Each participant receives two home visits conducted by the group facilitator during treatment. The first home visit takes place within the first three weeks of treatment, and includes treatment planning and assessment of home safety and hygiene. The second visit takes place near the end of treatment, within the last 2 weeks of treatment. This visit entails assessing changes in their home post-treatment and again conducting home safety and hygiene assessment. The visits are approximately 30 min to an hour. Participants may refuse home visits; those who refuse are asked to provide pictures of their homes to enable an estimation of clutter levels, home safety and hygiene. The CBT group facilitators assign clutter buddies based on participants' geographic proximity to each other, level of clutter observed

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at the first home visit, and self-reported motivation. Similarly, participation in this component is not mandatory, and participants can refuse to work with a clutter buddy. 2.9. BiT group treatment 2.9.1. Procedures Participants in the BiT condition receive 15 sessions of group therapy over 20 weeks (5 weeks of break within the treatment, see Table 2), based on a structured treatment manual “Buried in Treasures: Help for Compulsive Acquiring, Saving, and Hoarding” [13] adapted from the individual CBT workbook for hoarding. In this model, one to two trained peers with personal lived experience of hoarding guide the participants through the BiT workbook. Treatment delivery of BiT is overseen via weekly supervision by a peer mentor trained in the BiT manual and a clinician (PhD level nurse) who specializes in hoarding behavior. To monitor fidelity and consistency in delivering the BiT treatment, one of the co-developers of the BiT who serves as the Project Consultant will observe three sessions. One or both of the two BiT supervisors will observe an additional three sessions. 2.9.2. Delivery Each session is 2 h in length and consists of weekly check-ins, psychoeducation about hoarding, developing understanding and awareness of one's hoarding symptoms and patterns, behavior modification, cognitive restructuring, goal-setting, motivational enhancement, in vivo and imaginal exposure for discarding and acquisition, and executive skills training (organization, sorting, planning, decision-making, problem-solving, etc.). As in the CBT group, homework is expected (reading, exercises, and personal de-cluttering). Peer facilitators call each member of the group weekly prior to the group meeting to check in and field questions, if any. In addition, participants in the BiT group are asked (although not required, in keeping with the philosophy of supportive rather than directive intervention in this type of treatment) to identify a clutter buddy, whose role will be similar to that of the clutter buddies in the CBT group. However, BiT participants are not assigned clutter buddies. The BiT treatment also does not include home visits. 2.10. Measures 2.10.1. Screening The Saving Inventory-Revised (SI-R) [20], is a 23-item self-report questionnaire with 3 subscales assessing clutter, difficulty discarding, and excessive acquisition. The SI-R has good internal and test-retest reliability, and concurrent and divergent validity in clinical and non-clinical samples [21,22]. The UCLA Hoarding Severity Scale (UHSS) [23] is a 10-item clinicianadministered instrument designed for use in conjunction with a clinician interview. It provides the opportunity to probe for further details of hoarding behaviors and to address discrepancies in answers that might arise with a self-administered questionnaire. The UHSS assesses clutter, acquisition, and difficulty discarding, as well as the individual's level of shame and impairment in social relationships due to hoarding, procrastination, and difficulty making decisions. The Clutter Image Rating Scale (CI-R) [24] is a series of 9 photographs each of a kitchen, living room, and bedroom depicting varying levels of clutter, and is used as an adjunct measure to visually assess hoarding severity. Participants select the photograph that most closely resembles each of the three rooms in his/her home. Scores of ≥ 4 on each of the three rooms are considered clinically significant. Internal consistency, test-retest reliability and inter-rater reliability are high [24]. 2.10.2. Diagnostic assessments The Structured Interview for Hoarding Disorder (SIHD) [25] is administered to confirm a diagnosis of HD. The SIHD is a semi-structured

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clinical interview designed to assess for HD according to the proposed DSM-5 criteria. The SIHD assesses hoarding behaviors and distress and interference associated with hoarding behaviors and/or with discarding items, as well as assessing for potential confounders or alternate diagnoses, such as autism or schizophrenia. The SIHD is a useful adjunct to selfreport measures, as it incorporates the judgment of an experienced clinician. This interview takes approximately 30 min to administer. The Mini International Neuropsychiatric Interview (MINI) is a brief, structured screen for lifetime and current history of psychiatric disorders. The computer-assisted interview, MINI 6.0, takes approximately 15 to 45 min to administer, depending on the level of psychiatric comorbidity. It assesses for presence of all major mood, anxiety, psychotic and substance use disorders, among others [26]. This brief diagnostic screen is in part used to identify and catalog psychiatric disorders that may affect treatment adherence and response. The Montreal Cognitive Assessment (MoCA) is a screening instrument for cognitive impairment and dementia [27,28]. The MoCA assesses different cognitive domains (i.e., attention and concentration, executive functions, memory, language, visuoconstructional skills, conceptual thinking, calculations, and orientation), takes approximately 10 min to administer, with a total possible score of 30 points. A score of 26 or above is considered to be in the normal range. Scores below 18 indicate moderate or severe cognitive impairment, while scores between 18 and 26 indicate mild cognitive impairment. A score of 18 or above is required for inclusion in the study. 2.10.3. Additional hoarding related self-report measures The Savings Cognition Inventory, Revised (SCI-R) is a 24-item scale that was developed to measure specific beliefs and attitudes related to hoarding behaviors, including memory, value of possessions, emotional comfort, loss, control over possessions, and responsibility [29]. Questions relate to saving objects and reasons for doing so. For example, a question related to memory reads “Saving this means I do not have to rely on my memory”, while a value item reads “I will never be able to replace this item.” Items are scored on a 1–7 scale (“not at all” to “very much”). The SCI-R has excellent internal consistency and good convergent and discriminant validity with other measures of hoarding compared to measures of general anxiety or depression [30]. The Activities of Daily Living Scale in Hoarding Disorder (ADL-H) [31] is a 15-item self-report questionnaire that measures hoarding specific difficulties or problems that may impact daily functioning. It includes questions on activities affected by clutter or hoarding, problems in the home, and safety issues, each on a scale of 1–6. The ADL-H has good internal consistency, test-retest reliability, and inter-rate reliability. 2.10.4. Psychiatric co-morbidities The Beck Depression Inventory-II (BDI) [32] is a 21-item self report scale that measures severity of depression. This measure is widely used and its reliability and validity are well established across populations and cultural groups. Current and past depression symptoms are assessed both pre- and post-treatment as these symptoms may influence treatment adherence and treatment response. The Beck Anxiety Inventory (BAI) administered [33] is a 21-item self report scale that measures severity of anxiety. This measure is widely used and its reliability and validity are well established across populations and cultural groups. Current and past anxiety symptoms are assessed both pre- and post-treatment as these symptoms may influence treatment adherence and treatment response. 2.10.5. Homework and treatment evaluation During treatment, all participants complete a weekly Homework Completion Form developed by the MHASF consisting of six questions about their previous week's homework assignment, including the amount of time spent on sorting, organizing, or discarding. They also complete a bi-weekly Group Treatment Evaluation Form, also

developed by the MHASF and modified for this study. Bi-weekly assessment is given on odd number weeks starting with the first session for a total of eight assessment times. This form consists of 13 questions that ask the participants to rate the quality of the treatment group, their progress in the group, clutter buddy assignment, and hope for their hoarding behavior, among other questions, from Excellent to Poor. Participants are also asked to note any initiation of or changes in mental health treatment, including medications, therapy or other forms of treatment for HD or other psychiatric conditions that have taken place during the treatment on their biweekly evaluations. 2.10.6. Neuropsychological measures (NP) Neuropsychological assessments are conducted pre- and post-treatment by a research assistant trained in the administration, scoring, and interpretation of psychological assessments. The research assistant is overseen and supervised by a neuropsychologist. The NP battery was designed to cover a broad array of executive functions using multiple assessments for each cognitive domain (see Table 1), as well as to minimize participant burden. The battery takes, on average, 1.5 h to complete. All tests are administered according to standardized protocols, and alternate NP forms for each measure are used to decrease practice effects in the post-treatment assessment. Data are double scored and double entered and both the research assistant and supervising psychologist are blinded to participant group assignment. Tests assessing each cognitive domain are detailed below. The Delis Kaplan Executive Function System (DKEFS) Sorting Test [34], is a test of visual categorization and problem solving ability, cognitive flexibility, and ability to maintain cognitive set. An age-corrected scaled score for the number of correct categories completed, total errors, and the time required to complete the first sort are the outcome variables. WAIS III Block Design [35] subtest measures visual spatial processing and problem solving. The outcome variable is an age-corrected scaled score for the total number of correct responses. The Connors Continuous Performance Test II [36] (CPT) measures sustained visual attention. Age-corrected scaled scores for reaction time will be utilized as a measure of information processing speed. The Symbol Digit Modalities Test- Oral version [37] (SDMT) measures information processing speed, attention, and working memory. The outcome variable is an age- and education-corrected scaled score for the total number of correct responses. The Stroop Color Word Test [38] (SCWT) examines response inhibition and information processing speed, as well as cognitive flexibility, impulsivity, and cognitive set shifting. Hopkins Verbal Learning Test-Revised [39] (HVLT-R) assesses verbal learning and memory functioning. The primary outcome variable will be age-corrected scaled scores for the total number of correct responses on the learning and the delayed recall trials. Brief Visuospatial Memory Test-Revised [40] (BVMT-R) measures visual memory. The outcome variables are age corrected scaled scores for the number of total correct responses on the learning trials and the delayed free recall trial. Wechsler Adult Intelligence Scale-Third Edition Digit Span subtest [41] (Wechsler, 1997) This test assesses auditory working memory and focused attention. The outcome variable being used for this subtest is an age-corrected scaled score based on the total number of correct responses provided. The Iowa Gambling Test (IGT) [42] measures executive functioning and uses card deck selection to assess the ability to forgo immediate gain for a longer-term successful outcome. It simulates real life decision making strategy by factoring ambiguity, awards, and penalties. The National Adult Reading Test [43] (NART) is a clinically validated measure utilized to estimate the premorbid intelligence of individuals suspected of cognitive decline. The outcome variable utilized was the estimated Wechsler Adult Intelligence Scale full scale IQ score based on the number of correct responses on this measure. Therefore, the NART is assessed prior to treatment only.

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2.11. Assessment schedule All participants are assessed at screening, pre-treatment, during treatment (conducted bi-weekly to assess changes in clutter and treatment, for example), and within one month post-treatment. After meeting initial eligibility and prior to coming in to UCSF for a pre-treatment evaluation, participants complete the screening questionnaires, including a questionnaire that assesses beliefs about the efficacy of the two types of treatment and their preferences for each form of treatment. HD diagnoses are confirmed by clinical interview using the SIHD, and eligible participants receive the MINI, MoCA, and the NP assessment at the same in-person visit. Once treatment has begun, participants complete weekly homework forms and bi-weekly group evaluations. After treatment concludes, participants are invited back to UCSF for NP assessment. Total time for all pre-treatment assessment (not including NP) is approximately 1.5 h; total time for the post-treatment assessment is approximately 30 min (not including NP). The duration of the NP assessment conducted at pre-treatment and post-treatment is an additional 1.5 h. 2.12. Outcome and predictor variables The primary outcome variable is pre- to post-treatment change score on the SI-R, and the primary predictor variable is group status (CBT vs. BiT). Additional secondary outcomes of interest include change scores (pre- to post-treatment) on the ADL-H and SCI (measuring HDrelated functional impairment and cognitions, respectively), categorization ability as measured by the DKEFS sorting task, and speed of information processing as measured by the CPT. Additional predictor variables of interest include stated group preference (BiT vs. CBT) pretreatment, demographic characteristics such as gender, age, socioeconomic status, race and ethnicity, sexual identity or preference, insurance status, geography, and psychiatric status. 2.13. Hypotheses 2.13.1. Primary outcome We hypothesize that BiT will be as effective as CBT for HD and that both treatment types will reduce hoarding severity by at least 10 points (clinically meaningful) on the SI-R. With a sample size of 150 participants per arm, we will have 80% power to demonstrate non-inferiority if the BiT mean is no more than 2.9 points below (i.e., worse) than the CBT mean. A difference of 3 points or less on the SI-R is not likely to be clinically meaningful, and therefore, is sufficient to demonstrate non-inferiority between treatment types. 2.13.2. Secondary outcomes 2.13.2.1. Executive dysfunction. We hypothesize that some aspects of cognitive dysfunction in HD will be associated with increased hoarding behaviors. Specifically, we hypothesize that lower scores on measures of visual memory & learning will be associated with increased hoarding behaviors. We hypothesize that response to both types of treatment will be associated with improvement in executive functioning. Specifically, we hypothesize that improved information processing speed post-treatment will be correlated with improved treatment response, and that improvement in categorization may also be correlated with treatment response. In addition, as an exploratory aim, we will examine whether neurocognitive function predicts and/or changes treatment outcome. 2.13.2.2. Acceptability and preference of treatment. We hypothesize that most participants will find both treatments acceptable, but will have a slight preference for one over the other. For those individuals who do exhibit a strong preference for a specific treatment, we hypothesize that preference will be associated with treatment adherence and

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outcome (e.g., those that strongly prefer CBT but are randomized to BiT will have poorer treatment outcomes, and vice versa). 2.13.3. Exploratory variables We will explore the potential moderating effects of individual characteristics (e.g., insurance, age), psychiatric symptoms (e.g., depressive and anxiety symptoms), and pre-treatment cognitive function on treatment response and adherence. 2.14. Statistical analyses 2.14.1. Sample size and power The sample size for this study will be 300 participants total (150 per treatment arm) recruited and treated over three years. This is feasible based on our pilot data and the estimated prevalence of HD in the San Francisco Bay Area (12,000–25,000 adults). We chose the sample size for this study (N = 300 total, N = 150 per arm) using power calculations based on the mean improvement seen in our pilot data from CBT and BiT groups conducted at MHASF. Participants will be assigned to their treatment group using a computer generated randomization and concealment procedure, stratified by gender and geographic location. The study biostatistician will generate a list for random assignment using Proc PLAN in SAS. With a non-inferiority approach, larger sample sizes allow for more precise estimates of the treatment effect, and therefore, the hypothesis of non-inferiority can be tested for smaller group differences. With a sample size of 150 participants per arm, we will have 80% power to demonstrate non-inferiority if the BiT mean is no more than 2.9 points below (i.e., worse) than the CBT mean. A three-point difference between the two groups is unlikely to be clinically meaningful, and therefore, any difference between the groups that is smaller than 3 points will signify that the two treatment types are equally effective. Effect sizes will be estimated using the standard methods based on the outcome of interest, standardized mean differences, and transformed differences of proportions. 2.14.2. Analytic approach In this trial design, the hypothesis to be tested is that BiT is not inferior (i.e., is equally as effective) to CBT (the current standard of care), and the alternative hypothesis is that BiT is inferior to CBT. To ensure that one group is not significantly outperforming the other, leading to an inequity in treatment for study participants, a preliminary non-inferiority test will be conducted at approximately the midway point of the study (interim analysis), blinded to group (labeled group A and group B). The Data Safety Monitoring Board will review the results of these interim analyses and determine whether the study should continue to completion based on the interim results. A difference of b10 points on the SI-R between groups is considered to be sufficient evidence of non-inferiority at this early stage, as sample sizes will be comparatively small, and the analyses will not be corrected for potential confounders or covariates of interest. The study personnel will be blinded to the results of the interim analysis. At the completion of the study, comparisons will be appropriately corrected for having conducted the interim analyses by using O′Brien and Fleming's approach of a single interim analysis [44]. This approach allows for a comparison of treatment conditions while maintaining the overall Type I error rate at the pre-specified 0.05 level. For each set of analyses, standard methods to summarize and describe the collected data will be used. This will include a careful examination of rates and patterns of participant attrition and a tally of the number who meet criteria for clinically meaningful change (SI-R change ≥10 points), clinically significant change (SI-R change ≥14 points), and remission (post-test SI-R of b 42). If there are missing data, we will test to see if this is related to any of the baseline measures and if it differs between conditions. If so, this will be taken into account in the interpretation of results. And if feasible, multiple imputation will be used. All

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analyses will be conducted under the intent-to-treat principle. Individuals will be analyzed within their assigned treatment groups (CBT or BIT), even if they are found to have been participating in the other form of treatment outside of the study. However, we note that this is extremely unlikely, as to our knowledge; there are no other similar treatment groups available in the Bay Area, outside of the MHASF, our community partner. The main study objective will be met by testing the first hypothesis using a one-tailed t-test for non-inferiority comparing the mean SI-R scores between treatment conditions. If, however, preliminary analysis indicates unexpected differences by condition, a linear model will be used to include any potentially confounding covariates. The same approaches will be used to examine the ADL-H and the SCI-R change scores in secondary exploratory analyses. To test reduction in hoarding severity on the SI-R by at least 10 points (clinically meaningful), a linear model incorporating repeated measures and a time-by-condition interaction will be used. We will assess individual characteristics that are associated with treatment response by the estimation and testing of a model of change in SI-R scores, which includes individual measures including insurance status, socioeconomic and demographic factors, and clinical and neuropsychological factors. This analysis will be conducted across both treatment arms and, for any factor which is significant, a treatment condition by factor interaction term will be tested to determine if the predictor functions the same regardless of treatment. In all analyses, modern methods for working with missing data (full information maximum likelihood) will be used. This will allow us to incorporate baseline data into the estimation of models for those who drop out of the study prematurely. As we will have outcome data mainly for those who completed treatment, in secondary analyses we will also re-estimate our statistical models under the assumption that those who dropped out and were unable to be re-assessed had no change in outcome. Further, we will model dropout (both number of sessions and completer-versus-not) using baseline measures to estimate what characteristics predict completion. We will assess participant preferences for elements incorporated in CBT or BiT and examine whether these preferences are associated with treatment outcome. These analyses parallel those conducted to test treatment response predictors. 3. Discussion Hoarding Disorder is a chronic neuropsychiatric disorder associated with high levels of individual and family distress, social disruption, impairment at work and at home, and safety risks [45,46]. In addition to the toll on the individual, HD poses a great public safety concern that negatively impacts time and financial resources of community service agencies [46–48]. Treatment options include group and individual psychotherapy. However, these treatments are not available to many individuals with HD, due to the lack of access to mental health professionals with specialized HD training [16]. This randomized clinical trial attempts to address this gap in services by comparing a peer-facilitated treatment to the traditional standard of care treatment in real world conditions. If our trial shows that both treatments are equally effective, it could greatly increase our ability to serve more individuals by removing some of the key barriers to accessibility. The outcomes of this study will also provide information about predictors of treatment that will allow providers to tailor their treatment of HD to the individual, thereby potentially improving outcomes. Group treatment provided by trained peers (with or without lived experience) may decrease obstacles to accessibility and reduce stigma. If our study's findings indicate that a manualized peer-facilitated support group is as effective than a group facilitated by a mental health professional with specialized training, it could potentially provide opportunities for the many individuals who are cut off from services due to the lack of providers in their community or are reluctant to

obtain services due to fears of being judged. Dissemination of the trained peer model would increase the likelihood that individuals could receive treatment from facilitators within their own communities. The successful launch and completion of this clinical trial from study design through recruitment and implementation highlight our academic and community partnership, and reflect our efforts to personalize care for individuals with HD. Due to this partnership, we are well-positioned to start the process of identifying individual characteristics that predict treatment response. Because our study was designed to be generalizable to the larger HD community, we will not exclude individuals based on co-occurring psychiatric illness or substance use, demographic or socioeconomic characteristics, geography, immigration status, or insurance status. In fact, all efforts are made to include men and women from all ethnic, sexual, and socioeconomic groups. We also made a concerted effort to include older individuals. Using our broad inclusion criteria, we aim to have a heterogeneous study population that is representative of the hoarding population at large, greatly increasing the external validity of the results. In addition to the primary outcome of comparing the effectiveness of BiT and CBT, our findings will allow for the identification of individuals who are more likely to benefit from BiT compared to CBT and vice versa. This study could start to shed light on the relationship between individual characteristics and HD, as well as others, such as the role of socioeconomic positioning and participants' strong preferences for a mental health professional (vs. peer). We may also examine specific characteristics of treatment and/or treatment engagement such as the use and effectiveness of group assigned clutter buddies, adherence to homework assignments, and provider characteristics. Finally, impaired cognitive functioning could also negatively affect treatment outcome, increase drop-out rate, and increase and maintain participants' frustration and distress level throughout the treatment. Thus, identifying and understanding participants' cognitive profile may increase treatment retention and outcome. Ultimately, with this study, we may tailor the most appropriate path to care for an individual based on their neuropsychological, psychological, and treatment profile, which will further enhance treatment options and outcome. 3.1. Limitations Despite its potential impact, there are several limitations to our treatment study. Though there is a clinician administered measure, many of the measures used in this study rely on self-report measures. Also, assessors are blind to condition during the pre-assessment but not thereafter, which could introduce bias during treatment. There are a few areas in which the treatment conditions differ. Unlike its counterpart, the BiT treatment does not include home-based assessments. Future studies that include home visits in both treatment conditions can determine the additive effect of home visits. Group CBT and BiT are also not equivalent in number of sessions and breaks taken during treatment. It remains to be seen if an extra session of therapy or an extra week of break to either practice skills learned or to attend to non-hoarding matters is a vital component to group cohesiveness or treatment adherence, and hence treatment effectiveness. Lastly, the number of facilitators can also vary from one to two from group to group, which decreases our ability to rule out this reason for any reduction in hoarding symptoms or behaviors. Group treatments, in general, may not be appropriate for all individuals. As in other mental illness treatments, despite the social support and normalization it provides, the same avenue for treatment effectiveness may be an obstacle to group treatment due to perceived stigma. BiT may also not be appropriate for those individuals with a substantial burden of psychiatric symptomatology or with neurocognitive deficits that may be better served in a mental health setting. However, it is important to note that although highly complex behavioral patterns of an individual, whether it be maladaptive psychiatric symptoms or neurocognitive impairment, may intuitively be deemed a better fit for

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a specialized mental health care provider, it is an empirical question that this study could start to elucidate. Our study will evaluate whether either type of group can be effective for individuals with such complex neuropsychiatric and psychiatric profiles. In spite of our recruitment attempts to catch a wider net and serve as many people as possible, we realize that there is a significant segment of the population that may not be seeking help. Although there is greater generalizability due to our community partner's primary role in recruitment, the results of our findings may not extend to communities outside of an urban and academic setting. Additionally, longitudinal studies are needed to determine whether treatment gains can be durable months and years after treatment ends. Therefore, implementing follow-up assessments or evaluating continued treatment support is needed to provide optimal care for individuals with HD. Each of these areas represents important directions for future research efforts. 3.2. Summary Hoarding disorder is prevalent and debilitating. Both of the treatment models offered in our study have their own merits and have been deemed effective in prior studies. However, peer-led treatment holds particular promise by increasing access to care. Our study could offer additional information that both consumers and providers can use to make informed decisions regarding their mental health care. Our innovative community-academic partnership is a significant step toward ameliorating the pernicious symptomatology of HD and improving patients' quality of life. It is this collaboration that is leading us to our scientific understanding and advances in HD treatment. The caveats notwithstanding, this trial represents significant advances in HD treatment with benefits both to the individual and to their care providers and could inform personalized medicine in the future for an often overlooked and underserved population. Acknowledgments This work was supported through a Patient-Centered Outcomes Research Institute (PCORI) Assessment of Prevention, Diagnosis, and Treatment Options Program Award (#6000). All statements in this report are solely those of the authors and do not necessarily represent the views of the Patient-Centered Outcomes Research Institute (PCORI), its Board of Governors or Methodology Committee. The authors would like to thank Gillian Howell, Julian Plumadore, Lee Schuer, Chia-Ying Chou, and especially the study participants for their contributions to the Help for Hoarding study. References [1] American Psychiatric Association, Diagnostic and statistical manual of mental disorders, American Psychiatric Association (2013). [2] J.R. Grisham, M.M. Norberg, Compulsive hoarding: current controversies and new directions, Dialogues Clin. Neurosci. 12 (2010) 233–240. [3] J.F. Samuels, et al., Prevalence and correlates of hoarding behavior in a communitybased sample, Behav. Res. Ther. 46 (2008) 836–844. [4] J.N. Constantino, R.D. Todd, Autistic traits in the general population: a twin study, Arch. Gen. Psychiatry 60 (2003) 524–530. [5] R.C. Kessler, et al., Lifetime prevalence and age-of-onset distributions of DSM-IV disorders in the national comorbidity survey replication, Arch. Gen. Psychiatry 62 (2005) 593–602. [6] R.O. Frost, R.C. Gross, The hoarding of possessions, Behav. Res. Ther. 31 (1993) 367–381. [7] J.R. Grisham, R.O. Frost, G. Steketee, H.-J. Kim, S. Hood, Age of onset of compulsive hoarding, J. Anxiety Disord. 20 (2006) 675–686. [8] H.J. Kim, G. Steketee, R.O. Frost, Hoarding by elderly people, Health Soc. Work 26 (2001) 176–184. [9] J. Best-Lavigniac, Hoarding as an adult: overview and implications for practice, J. Psychosoc. Nurs. Ment. Health Serv. 44 (2006) 48–51. [10] D.F. Tolin, R.O. Frost, G. Steketee, J. Muroff, Cognitive behavioral therapy for hoarding disorder: a meta-analysis, Depress. Anxiety 32 (2015) 158–166.

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