PTSD's underlying symptom dimensions and relations with behavioral ...

Journal of Anxiety Disorders 27 (2013) 645–651

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Journal of Anxiety Disorders

PTSD’s underlying symptom dimensions and relations with behavioral inhibition and activation Ateka A. Contractor a , Jon D. Elhai a,b,∗ , Kendra C. Ractliffe c,1 , David Forbes d a

Department of Psychology, University of Toledo, Mail Stop #948, 2801 West Bancroft Street, Toledo, OH 43606-3390, United States Department of Psychiatry, University of Toledo, Ruppert Health Center, Basement, Room # 0079, 3000 Arlington Avenue, Toledo, OH 43614, United States Disaster Mental Health Institute, University of South Dakota, 414 East Clark Street, Vermillion, SD 57069-2390, United States d Australian Centre for Posttraumatic Mental Health, Department of Psychiatry, University of Melbourne, Locked Bag 1, Heidelberg West, Vic 3081, Australia b c

a r t i c l e

i n f o

Article history: Received 10 April 2013 Received in revised form 17 July 2013 Accepted 26 July 2013 Keywords: Posttraumatic stress disorder Factor analysis Behavioral inhibition Behavioral activation Avoidance behavior

a b s t r a c t Reinforcement sensitivity theory (RST) stipulates that individuals have a behavioral activation system (BAS) guiding approach (rewarding) behaviors (Gray, 1971, 1981), and behavioral inhibition system (BIS) guiding conflict resolution between approach and avoidance (punishment) behaviors (Gray & McNaughton, 2000). Posttraumatic stress disorder (PTSD) severity overall relates to both BIS (e.g., Myers, VanMeenen, & Servatius, 2012; Pickett, Bardeen, & Orcutt, 2011) and BAS (Pickett et al., 2011). Using a more refined approach, we assessed specific relations between PTSD’s latent factors (Simms, Watson, & Doebbeling, 2002) and observed variables measuring BIS and BAS using 308 adult, trauma-exposed primary care patients. Confirmatory factor analysis and Wald chi-square tests demonstrated a significantly greater association with BIS severity compared to BAS severity for PTSD’s dysphoria, avoidance, and re-experiencing factors. Further, PTSD’s avoidance factor significantly mediated relations between BIS/BAS severity and PTSD’s dysphoria factor. © 2013 Elsevier Ltd. All rights reserved.

1. Introduction According to reinforcement sensitivity theory (RST), the behavioral activation system (BAS) guides behaviors toward positive/rewarding situations (Gray, 1971, 1981); the behavioral inhibition system (BIS) resolves conflict between approach toward a reward and avoiding punishment/threat (Gray & McNaughton, 2000). Some research indicates a significant relationship for posttraumatic stress disorder (PTSD) overall with BIS (e.g., Maack, Tull, & Gratz, 2011; Myers, VanMeenen, & Servatius, 2012) and BAS (Pickett, Bardeen, & Orcutt, 2011). Little is known about the specific PTSD symptom dimensions most related to BIS and BAS, and explanatory mechanisms underlying such relationships. 1.1. BAS and BIS dimensions RST (Gray, 1971) proposes three major brain mechanisms underlying behavior. First is the fight/flight system (FFS) (Gray, 1971), renamed as fight-flight-freeze system (FFFS) in the

∗ Corresponding author at: Department of Psychology, University of Toledo, Mail Stop #948, 2801 West Bancroft Street, Toledo, OH 43606-3390, United States. Tel.: +1 419 530 2829; fax: +1 419 530 8479. URL: http://www.jon-elhai.com (J.D. Elhai). 1 Kendra Ractliffe is now affiliated with the Palo Alto Veterans Affairs Medical Center. 0887-6185/$ – see front matter © 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.janxdis.2013.07.007

revised RST (reviewed in Corr, 2004; Gray & McNaughton, 2000; reviewed in Smillie, Pickering, & Jackson, 2006). FFFS guides escape/aggressive behaviors in response to punishing/nonrewarding stimuli. The FFFS is not our focus here, as it has relatively little empirical research compared to other RST constructs with no instrument to measure it. However, this concept will be considered in the paper given its important role in the revised RST as explained later. The second RST mechanism is BAS, a reward system guiding approach behaviors, with sensitivity to situations of reward, and terminating feared/punishing stimuli (Gray, 1971, 1981). With the propensity to engage in undesirable behaviors to avoid a feared stimulus, approach behaviors could be impulsive with possibly detrimental consequences (Gray, 1971, 1981), supported by Casada and Roache (2005). Lastly, BIS guides behaviors in punishing, non-rewarding or novel situations, involving suppression (i.e., passive avoidance of negative stimuli), and increased attention/vigilance to the environment (Gray, 1971, 1981). The revised RST re-conceptualized BIS’s role as that of conflict resolution between concurrently activated BAS (approach toward reward) and FFFS (avoidance from punishment), representing approachavoidance conflict and contributing to anxiety (reviewed in Corr, 2004; Gray & McNaughton, 2000; reviewed in Smillie et al., 2006). RST components differentially relate to several mental health conditions (e.g., Hughes, Moore, Morris, & Corr, 2012). BIS is associated with Cluster C personality disorders (Pastor et al., 2007), while BAS is more associated with Cluster B personality disorders

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A.A. Contractor et al. / Journal of Anxiety Disorders 27 (2013) 645–651

Table 1 Models of PTSD factor structure. PTSD symptoms

DSM-IV

Simms et al.

B1. Intrusive thoughts B2. Nightmares B3. Reliving traumas B4. Emotional cue reactivity B5. Physiological cue reactivity C1.Avoidance of thoughts C2. Avoidance of reminders C3.Amnesia for traumatic event C4.Loss of interest C5. Detachment C6.Restricted affect C7. Hopelessness D1. Sleeping difficulties D2. Irritability/anger D3. Concentration difficulties D4. Hypervigilance D5. Easily startled

R R R R R A/N A/N A/N A/N A/N A/N A/N H H H H H

R R R R R A A D D D D D D D D H H

Note. R, reexperiencing; A, avoidance; N, numbing; H, hyperarousal; D, dysphoria.

(Pastor et al., 2007), and ADHD (Johnson, Turner, & Iwata, 2003), and both BIS and BAS relate to bulimia (Loxton & Dawe, 2006). Little research has investigated PTSD’s relation with RST components. PTSD’s increased physiological (hyperarousal) and inhibited (avoidance) responding (Casada & Roache, 2005) are conceptually similar to BAS and BIS, respectively. Further, PTSD relates to external measures of anxiety (Myers et al., 2012), and impulsivity (Weiss, Tull, Viana, Anestis, & Gratz, 2012), in turn relating to BIS and BAS respectively (Gray, 1971, 1981). Thus, the RST is relevant to understanding PTSD’s subcomponents. 1.2. PTSD’s underlying dimensions Previous research has demonstrated that PTSD’s underlying dimensions do not support the DSM-IV tripartite model (reexperiencing, effortful avoidance/numbing, hyperarousal) based on confirmatory factor analysis (CFA) (reviewed in Elhai & Palmieri, 2011; Yufik & Simms, 2010), thus leading to the development of alternative four-factor models such as the dysphoria model (Simms, Watson, & Doebbeling, 2002). PTSD’s dysphoria model retains the re-experiencing factor of the DSM-IV model, but creates a new dysphoria factor with the DSM-IV hyperarousal PTSD items D1–D3, and numbing/avoidance items C3–C7. This model is based on the literature supporting a general dysphoria or emotional distress component to the mood and anxiety disorders (Watson, 2005, 2009). Table 1 represents item mappings for PTSD’s dysphoria model. The current study focuses on this dysphoria model, based on strong empirical support (reviewed in Elhai & Palmieri, 2011; Yufik & Simms, 2010), and evidence of a slightly better fit than other PTSD models (meta-analyzed in Yufik & Simms, 2010). Further, the current study attempts to analyze the relation of specific (i.e., trauma-related such as re-experiencing) and non-specific (i.e., general distress represented by dysphoria) PTSD factors with RST as best conceptualized by the dysphoria model to capture purer PTSD constructs, with subsequent implications for treatment and comorbidity explanations.

et al. (2011) in a sample of trauma-exposed female college students; however the positive PTSD–BIS relationship was contingent on avoidance of distressing private events (e.g., thoughts and feelings) with maladaptive coping strategies. With the PTSD–BAS relation, there are mixed findings in the literature possibly attributed to the multidimensional nature of the BAS construct. While sensitivity to reward expectation as represented by one BAS dimension was negatively related to PTSD severity, functional persistence toward goals as assessed by another BAS dimension was positively related to PTSD severity (Pickett et al., 2011). In contrast to self-reports, Casada and Roache (2005) used performance-based measures of BAS and BIS, with results indicating that subjects with PTSD had a weakening BAS when perceiving little reward; however were insensitive to inhibition cues (active BAS) when perceiving reinforcement. It could be further said that the FFFS (avoidancedistress) and BAS (reward-achievement) conflict associated with PTSD symptoms may contribute to BIS severity as further elaborated. PTSD’s avoidance dimension in particular may be crucial in explaining relations between BAS/BIS and PTSD symptoms. Several PTSD theories and empirical studies have referenced the role of avoidance in the maintenance of PTSD symptoms (Maack et al., 2011; Myers et al., 2012). Based on stress response theory (reviewed in Brewin & Holmes, 2003; Horowitz, 1986) and emotional processing theory (Foa & Kozak, 1986; Foa, Steketee, & Rothbaum, 1989), PTSD’s avoidance of internal/external traumatic reminders is purported to reduce the emotional impact of traumatic event exposure in the short-run. Avoidance is also negatively reinforcing, reducing fear on exposure to conditioned traumatic reminders, based on PTSD fear conditioning theory (reviewed in Brewin & Holmes, 2003; Keane, Zimering, & Caddell, 1985). However, PTSD’s avoidance maintains and contributes to PTSD severity and distress by inhibiting emotional processing of traumatic memories (Foa & Kozak, 1986; Foa et al., 1989), and contributing to the re-experiencing of the trauma (Brewin, Dalgleish, & Joseph, 1996; Horowitz, 1986). The avoidance-distress relationship possibly represents the FFFS pathway (Gray & McNaughton, 2000). In contrast to PTSD’s avoidance, there is motivation toward reward achievement (Casada & Roache, 2005) based on BAS (Gray, 1971; Gray & McNaughton, 2000), however there is less reward expectancy and less satisfaction once the reward is achieved (Hopper et al., 2008). Distress and negative affect associated with PTSD symptoms (Marshall-Berenz, Vujanovic, & MacPherson, 2011; Pickett et al., 2011; Weiss et al., 2012) such as re-experiencing may decrease inhibition toward rewards (Casada & Roache, 2005), and consequently increase impulsive behaviors (following from an active BAS) (e.g., Marshall-Berenz et al., 2011; Weiss et al., 2012). Thus, emotion regulation difficulties may explain the PTSD–BAS relationship, with impulsivity relating to BAS (e.g., Aluja & Blanch, 2011) and PTSD (e.g., Ledgerwood & Petry, 2006; Weiss et al., 2012). Thus, conflict between FFFS (avoidance-distress path) and BAS (reward-achievement path) may relate to BIS activation, and subsequent feelings of anxiety (Gray & McNaughton, 2000). The aforementioned indicates BIS’s possible association with PTSD factors of avoidance and dysphoria, and BAS’s possible association with PTSD’s re-experiencing factor. 1.4. PTSD factors and BIS/BAS

1.3. PTSD and BIS/BAS PTSD severity relates to BIS (Casada & Roache, 2005; Gray & McNaughton, 2000; Myers et al., 2012; Pickett et al., 2011) and BAS (Pickett et al., 2011). To elaborate, Myers et al. (2012) found that self-reported behavioral inhibition correlated positively with increased PTSD severity, especially with PTSD’s avoidance in a sample of veterans. Similar results were obtained in a study by Pickett

Building on the study by Pickett et al. (2011), we aimed to investigate differential relations between PTSD’s dysphoria model latent factors and observed variables of scales measuring BIS and BAS. We use a sample of trauma-exposed medical patients, because trauma and PTSD are highly related to physical health problems (Pacella, Hruska, & Delahanty, 2013) and healthcare seeking (Elhai, North, & Frueh, 2005).


We first hypothesize that PTSD’s dysphoria factor will relate more to BIS than BAS. This is based on evidence indicating BIS’s relation with depression (e.g., Scott-Parker, Watson, King, & Hyde, 2012) and anxiety symptoms (e.g., Aluja & Blanch, 2011; Torrubia, Ávila, Moltó, & Caseras, 2001), both related to PTSD’s dysphoria factor (e.g., Gootzeit & Markon, 2011; Simms et al., 2002). In fact, BAS does not positively relate to depressive or anxiety symptoms (Johnson et al., 2003); rather negatively to depression because it contributes to positive experiences and expectations (Beevers & Meyer, 2002). Overall, avoidance of traumatic cues associated with BIS (Myers et al., 2012; Pickett et al., 2011) aimed at reducing PTSDrelated distress (dysphoria) in the short-run increases distress in the long-run (Foa & Kozak, 1986; Foa et al., 1989), thus reflecting dysphoria’s relation to BIS. Second, we hypothesize that PTSD’s avoidance factor will relate more to BIS than BAS based on previous findings (Myers et al., 2012; Pickett et al., 2011) and its goal to supposedly reduce distress on exposure to traumatic event cues (reviewed in Brewin & Holmes, 2003). Third, PTSD’s re-experiencing factor should be more associated with BAS than BIS, based on engagement in impulsive behaviors (active BAS) to obtain rewards and reduce emotional distress (Casada & Roache, 2005; O’Hare, Sherrer, Yeamen, & Cutler, 2009) related to PTSD’s re-experiencing symptoms (Aidman & Kollaras-Mitsinikos, 2006; Kotler, Julian, Efront, & Amir, 2001). 1.5. Role of PTSD’s avoidance factor Several PTSD theories emphasize the role of avoidance in maintaining PTSD symptoms (reviewed in Brewin & Holmes, 2003). We therefore investigated the role of PTSD’s avoidance in the relations between PTSD’s factors and BIS/BAS. For our fourth hypothesis, PTSD’s avoidance factor should mediate associations between BIS severity and PTSD’s dysphoria. While BIS potentially relates to dysphoria (stated above), PTSD’s avoidance may mediate that relationship by inhibiting emotional processing of traumatic memories and thereby influencing an increase in dysphoria (PTSD’s distress) in the long-run (Foa & Kozak, 1986). Thus, the association between BIS and increased distress is possibly exemplified if PTSD’s avoidance inhibits adaptive processing of trauma memories. Lastly, PTSD’s avoidance should mediate relations between BAS severity and PTSD’s dysphoria. BAS as represented by a desire for rewarding situations may be associated with avoidance of distressing traumatic reminders to escape their perceived dysphoric effects (Pickett et al., 2011). This avoidance coupled with increased BAS in turn may be associated with increased dysphoria symptom severity as already explained. The proposed hypotheses are important in understanding RST’s role in PTSD, with additional focus on PTSD’s avoidance factor. This study improves upon prior studies assessing relations between PTSD and BIS/BAS (e.g., Maack et al., 2011; Myers et al., 2011; Pickett et al., 2011) by assessing PTSD’s empirically-derived latent dimensions, rather than using PTSD as an overall construct or as observed subscale scores. 2. Method 2.1. Participants and procedure Data were collected from the waiting room of a primary care clinic, affiliated with a U.S. Midwestern state university’s medical school. Data collection occurred from January to June 2010, including adults (ages 18–65) consecutively presenting for medical appointments. A trained psychology graduate student invited participants for a brief, paper-and-pencil survey (without monetary compensation). An informed consent statement was used,

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approved by the University of South Dakota’s Institutional Review Board. Among 551 invited participants, 52 were excluded for not speaking/reading English, or not being a clinic patient. Further, 411 patients among the 499 eligible participants agreed to participate (82% response rate). The 411 participants were restricted to those endorsing at least one traumatic event, and not missing more than 30% of PTSD items (5 items or more) or SPSRQ items (14 items or more), resulting in 308 participants. Nominal amounts of missing data (≤5 items per subject) were estimated using multiple imputation (MI) procedures (Graham, 2009) with SPSS 17 software. 2.2. Instruments Several measures were administered. 2.2.1. Demographic survey Information regarding age, gender, etc., was obtained. 2.2.2. Stressful Life Events Screening Questionnaire (SLESQ) The SLESQ is a 13-item self-report questionnaire assessing exposure to traumatic events according to the definition of DSM-IV PTSD Criterion A1 event. Item-level two-week test-retest reliability ranges from .31 to 1.00 (11 DSM-IV traumatic events), with good test-retest reliability of .89, and concurrent and convergent validity (Goodman, Corcoran, Turner, Yuan, & Green, 1998). We asked participants to indicate their most distressing event (if endorsing more than one trauma). Only participants who endorsed a traumatic event were queried about PTSD symptoms and included for the primary analyses of the study. 2.2.3. PTSD Symptom Scale-Self-Report (PSS-SR) The PSS-SR is a 17-item Likert-type self-report questionnaire of DSM-IV PTSD symptoms (Foa, Riggs, Dancu, & Rothbaum, 1993). The PSS-SR has good internal consistency with Cronbach’s alpha of .91 (Foa et al., 1993) and .94 (Coffey, Gudmundsdottir, Beck, Palyo, & Miller, 2006) (.94 in the present study), one-month test-retest reliability of .74, and convergent validity based on the Structured Clinical Interview for DSM (SCID) (Foa et al., 1993), and ClinicianAdministered PTSD Scale (CAPS) (Coffey et al., 2006). Further, the Cronbach alphas for the re-experiencing, avoidance, dysphoria, and hyperarousal subscales were .89, .76, .88 and .81 respectively. Participants rated PSS-SR items with a past-month time-frame based on their most distressing traumatic event. 2.2.4. Sensitivity to Punishment and Sensitivity to Reward Scale (SPSRQ) Based on Gray’s personality theory (Gray, 1971), the SPSRQ is a 48-item self-report binary response (“yes”/“no”) questionnaire with two scales: the Sensitivity to Reward scale (24 even numbered items) and Sensitivity to Punishment Scale (24 odd numbered items). The SP scale assesses BIS functioning (behavioral inhibition) in response to situations with aversive consequences, novelty and failure. The SR scale assesses BAS functioning (approach behaviors) with items referencing reward situations (e.g., money, social reinforcement) (Torrubia et al., 2001). Internal consistency is evidenced for the SP (alphas of .81–.83) (.85 in the present study) and SR scales (.74) (e.g., O‘Connor, Colder, & Hawk, 2004) (.75 in present study). SP relates to other BIS (Caseras, Àvila, & Torrubia, 2003; Dufey, Fernández, & Mourgues, 2011), and anxiety measures (Aluja & Blanch, 2011; Beck, Smits, Claes, Vandereycken, & Bijttebier, 2009) (e.g., Caseras et al., 2003; Torrubia et al., 2001). SR relates to other BAS (e.g., Cooper & Gomez, 2008), and impulsivity measures (e.g., Aluja & Blanch, 2011; Torrubia et al., 2001). Given the lack of substantial empirical support for this measure’s factor structure, the SR and SP scales were considered as observed variables for CFA.

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2.3. Effective sample characteristics The effective sample of 308 participants had a mean age of 42.51 years (SD = 11.63); a majority were female (n = 196, 63.6%). Most respondents were married (n = 88, 28.6%) cohabitating (n = 79, 25.6%), or single (n = 76, 24.7%). Most completed high school (n = 171, 55.5%) or college (n = 65, 21.1%). Additionally, a majority were employed, either full-time (n = 131, 42.5%) or part-time (n = 59, 19.2%). Further, most participants reported race as Caucasian (n = 247, 80.2%) or American Indian/Alaskan Native (n = 30, 9.7%). Hispanic/Latino ethnicity was reported by 23 respondents (7.5%). The most prevalent traumatic events endorsed included unexpected death of a family member, relative or close friend (n = 180, 58.6%), adult physical assault (n = 166, 53.9%), and child physical abuse (n = 136, 44.2%). The most prevalent worst traumatic events were unexpected death of a family member/close friend (n = 97, 31.9%), physical harm by parent/caregiver (n = 39, 12.8%), and lifethreatening accident (n = 34, 11.2%). Lastly, 259 participants (86%) reported initial feelings of fear, helplessness or horror in response to their worst trauma.

Table 2 Correlations between dysphoria model factors, SP and SR scales.

Reexperiencing Avoidance Dysphoria Hyperarousal SP scale SR scale

1

2

3

4

5

6

– .90** .89** .73** .29** .07

– .93** .87** .31** .17*

– .92** .33** .11

– .37** .17*

– .34**

–

Note. SP, sensitivity to punishment; SR, sensitivity to reward. * p < .05. ** p < .01.

Noteworthy is that mediation analyses were used with crosssectional data, which cannot account for causal mechanisms for PTSD and BIS/BAS (MacKinnon, Taborga, & Morgan-Lopez, 2002). However, the results if significant can help justify the time and expense invested in conducting similar longitudinal causation studies (Cole & Maxwell, 2003). Further, the terminology of “mediation” in the current study refers to more of a mechanism explaining the relation between variables, given the lack of temporal precedence of the proposed “mediator” (Kraemer, Kiernan, Essex, & Kupfer, 2008).

2.4. Analysis 3. Results Initially, SP (odd 24 items) and SR scale (even 24 items) scores were computed. Based on benchmarks of skewness > 2 and kurtosis > 7 (Curran, West, & Finch, 1996), these scales were normally distributed. Primary analyses with Mplus 6.12 software (Muthén & Muthén, 1998–2007) entailed three steps. First, confirmatory factor analysis (CFA) was computed to estimate fit of PTSD’s dysphoria model using PSS-SR items. Factor variances and error terms were scaled to “1,” using an alpha of .05 and two-tailed tests. SP and SR scale scores were treated as continuous variables, while PSS-SR items were treated as categorical (4 response options), hence using polychoric covariances, probit regression coefficients, and robust weighted least squares estimation with a mean- and variance-adjusted chisquare (Flora & Curran, 2004). A well-fitting (adequate) model has a comparative fit index (CFI) value and Tucker Lewis Index (TLI) value ≥ .95 (.90–.94), and root mean square error of approximation (RMSEA) value ≤ .06 (.07–.08) (Hu & Bentler, 1999). The second step entailed computing Wald chi-square tests of parameter constraints to test hypothesized relations between latent factors of PTSD’s dysphoria model and observed variables of SP and SR scales measuring BIS and BAS, respectively. Wald chisquare tests assess the null hypothesis that the difference between two correlations is zero, using alpha of .05. Specifically, Wald tests assessed if PTSD’s dysphoria factor (Hypothesis 1) and avoidance factor (Hypothesis 2) will be more associated with BIS than BAS. Further, Wald tests assessed if PTSD’s re-experiencing factor would be more associated with BAS than BIS (Hypothesis 3). The third step entailed conducting mediation analyses, assessing a chain of relations wherein an independent variable (IV) influences a mediator, in turn influencing the dependent variable (DV) (MacKinnon, Fairchild, & Fritz, 2007). Meditation was conducted as part of structural equation modeling using Mplus 6.12 software (Muthén & Muthén, 1998–2007). For the fourth and fifth hypotheses, PTSD’s dysphoria was the DV, and PTSD’s avoidance was the mediator; BIS was the IV in the fourth hypothesis, while BAS was the IV in the fifth hypothesis. Direct and indirect effects (Bollen & Stine, 1990) were computed. We used the path coefficient product approach to mediation, a modern recommended approach (MacKinnon, Lockwood, Hoffman, West, & Sheets, 2002); we computed standard errors using the delta method in conjunction with bootstrapping (MacKinnon, Lockwood et al., 2002).

Total PSS-SR scores averaged 12.02 (SD = 12.09). Using DSM-IV’s diagnostic algorithm of at least one re-experiencing, three avoidance/numbing, and two hyperarousal symptoms endorsed as “1” or higher (i.e., once per week or less) (Foa et al., 1993), 44.8% (n = 138) of trauma-exposed participants seeking medical treatment had a probable PTSD diagnosis (33.6% of the entire sample of 411 subjects met this threshold). The high prevalence of PTSD-probable cases is consistent with meta-analytic results indicating a large effect regarding PTSD’s relation with physical health problems (metaanalyzed in Pacella et al., 2013). Total SPSRQ scores averaged 19.55 (SD = 8.11); SR averaged 9.38 (SD = 4.29) and SP averaged 10.17 (SD = 5.58). CFA indicated a well-fitting PTSD dysphoria model according to majority of the fit indices, robust 2 (df = 113, N = 308) = 344.79, p < .001, CFI = .97, TLI = .97, RMSEA = .08 (90% CI: .072–.092). Further, CFA indicated a well-fitting combined model (PTSD’s dysphoria model, and SP/SR observed variables allowed to inter-correlate with each other and with PTSD factors) according to majority of fit indices, robust 2 (df = 139, N = 308) = 388.06, p < .001, CFI = .97, TLI = .97, RMSEA = .08 (90% CI: .067–.085). Using Wald tests, consistent with the first hypothesis, PTSD’s dysphoria factor was more related to SP (r = .33, p < .05) than SR (r = .11, p = .08), Wald 2 (1, N = 308) = 14.18, p < .05. Also consistent with the second hypothesis, PTSD’s avoidance factor was more related to SP (r = .31, p < .05) than SR (r = .17, p < .05), Wald 2 (1, N = 308) = 5.65, p < .05. Contradictory to the third hypothesis, PTSD’s re-experiencing factor was more related SP (r = .29, p < .05) than SR (r = .07, p = .22), Wald 2 (1, N = 308) = 14.94, p < .05. Table 2 displays inter-correlations between the dysphoria model factors, SP and SR scales. Consistent with the fourth hypothesis, PTSD’s avoidance mediated the relationship between SP and PTSD’s dysphoria (ˇ = .29, SE = .07, p < .001). Direct effects of SP on PTSD’s avoidance (B = .06, SE = .01, ˇ = .31, p < .001) and PTSD’s avoidance on PTSD’s dysphoria (B = 2.33, SE = .76, ˇ = .91, p = .002) were significant, with no significant direct effects between SP and PTSD’s dysphoria (B = .02, SE = .02, ˇ = .05, p = .337). Further, consistent with the fifth hypothesis, PTSD’s avoidance mediated the relationship between SR and PTSD’s dysphoria (ˇ = .16, SE = .07, p = .021). Direct effects of SR on PTSD’s avoidance (B = .04, SE = .02, ˇ = .17, p = .027) and PTSD’s


avoidance on PTSD’s dysphoria (B = .249, SE = .82, ˇ = .94, p = .003) were significant, with no significant direct effects between SR and PTSD’s dysphoria (B = −.03, SE = .03, ˇ = −.05, p = .247).

4. Discussion Prior literature indicates a relationship for PTSD severity with BIS (e.g., Myers et al., 2012; Pickett et al., 2011) and BAS functioning (Pickett et al., 2011). Further, research indicates PTSD’s relation with anxiety (e.g., Chemtob, Hamada, Roitblat, & Muraoka, 1994; Myers et al., 2012) and impulsivity (e.g., Ledgerwood & Petry, 2006; Weiss et al., 2012), the latter constructs associated with BIS and BAS, respectively (Gray, 1971, 1981). Testing specific latent-factor relations, most of hypotheses in this study were supported.

4.1. Relation with BIS As hypothesized, PTSD’s dysphoria and avoidance latent factors had a significantly greater association with BIS (SP scale) than BAS (SR scale). Exposure to a trauma and possible PTSD symptoms may be associated with BIS severity (Gray & McNaughton, 2000), conceptualized as concurrent activation of the FFFS (avoidance of distressing reminders of the traumatic event) (Maack et al., 2011; Myers et al., 2012; Pickett et al., 2011) and BAS (less sensitivity to inhibition on reward perception) (Casada & Roache, 2005). Thus, the aforementioned pathway explains the concurrent presence of avoidance with BIS activation. Further, distress consequent to the negative evaluation of traumatic events (Maack et al., 2011; Pickett et al., 2011), possibly captured by PTSD’s dysphoria factor is related with BIS activation in response to trauma exposure (Gray & McNaughton, 2000). Results are further consistent with research indicating common elements to dysphoria and BIS, specifically depression (e.g., Gootzeit & Markon, 2011; Marshall, Schell, & Miles, 2010; Scott-Parker et al., 2012), anxiety (Gootzeit & Markon, 2011; Scott-Parker et al., 2012; Simms et al., 2002; Torrubia et al., 2001), and negative affect (e.g., Forbes et al., 2011; Gootzeit & Markon, 2011; Watson, 2009). Thus, although PTSD’s avoidance and dysphoria significantly relate to BAS, this relation is weaker as compared to their relation with BIS based on the aforementioned explanations.

4.2. Relation with BAS In contrast to hypotheses, PTSD’s re-experiencing related more to BIS than BAS. Noteworthy is the non-significant relationship between PTSD’s re-experiencing and SR, contradictory to other studies (Aidman & Kollaras-Mitsinikos, 2006; Kotler et al., 2001). One explanation for this discrepancy is that SR may significantly relate to other PTSD latent factors such as avoidance and dysphoria in the current study. Thus, impulsive behavior may still serve its purported rewarding function of reducing negative emotional states related to some PTSD symptoms (Marshall-Berenz et al., 2011; Weiss et al., 2012), explaining the presence of substance usage (e.g., Cyders, Combs, Fried, Zapolski, & Smith, 2009; Stewart, Mitchell, Wright, & Loba, 2004), and less sensitivity to inhibition cues in PTSD (Casada & Roache, 2005). Second, BAS may be a multidimensional construct (Carver & White, 1994), not adequately represented with a undimensional scale such as the SR. Lastly, Gray’s (1971) proposed independence of the BIS and BAS (Caseras et al., 2003) has been recently challenged (Gomez & Gomez, 2005; Smillie et al., 2006) which could have influenced the current study’s findings.

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4.3. Mediating role of PTSD’s avoidance As hypothesized, PTSD’s avoidance significantly mediated relations between BIS/BAS severity and PTSD’s dysphoria. Theoretically, one could conceptualize BIS and BAS as functioning with PTSD’s avoidance in influencing changes in distress inherent in PTSD (represented by the dysphoria factor). Results emphasize the central role of PTSD’s avoidance when considering BIS/BAS functioning and PTSD symptoms, adding to prior theory (e.g., Foa & Kozak, 1986). 4.4. Implications This study has several implications. First, prior studies assessing relations between PTSD and BIS/BAS have used PTSD as an overall construct (e.g., Maack et al., 2011; Myers et al., 2011; Pickett et al., 2011). Given advantages of assessing structural relations using latent factors (e.g., capturing more heterogeneity within disorders) (Watson, 2009), this unique study contributes to understanding PTSD’s psychopathology in relation to BIS/BAS. In fact, sole reliance on a diagnosis to study the relation between psychopathology and BIS/BAS constructs is ineffective because diagnostic status explains only 10% of the variance in BIS/BAS scores (Johnson et al., 2003). Second, despite the importance of targeting PTSD’s avoidance symptoms for effective therapy (e.g., Foa & Kozak, 1986; Foa, Riggs, Massie, & Yarczower, 1995; Foa et al., 1989), our results highlight the role of avoidance in influencing PTSD’s dysphoria when one experiences concurrent behavioral inhibition/activation. The results support trauma-focused psychotherapy focusing on reducing behavioral inhibition (Rosellini, Fairholme, & Brown, 2011), and increasing behavioral activation (Jakupcak, Wagner, Paulson, Varra, & McFall, 2010). Lastly, BAS’s significant association with dysphoria (PTSD’s non-specific factor) and avoidance may represent possible shared variance between impulsivity and PTSD, a relation that is wellestablished (e.g., Weiss et al., 2012). Thus, heterogeneity in PTSD symptoms in relation with BIS/BAS possibly explains PTSD’s comorbidity with anxiety-based and impulse-based disorders, and PTSD’s decreased sensitivity to both rewarding and punishing situations (Elman et al., 2009). 4.5. Limitations and future directions The current study has several limitations. To begin with, the revised RST’s conceptualization of BIS includes FFFS and BAS activation, making it extremely difficult to differentiate FFFS from BIS activation, unless assessed separately. Thus, future research could use different measures of BIS and FFFS to distinguish their effects, and also consider interdependence of the BIS-BAS constructs (Gomez & Gomez, 2005; Smillie et al., 2006). Further, results are limited to primary care patients with limited ethnic and cultural diversity; the latter variable could be used as a covariate in future research. Some limitations relate to the “criterion A1 and A2” definitions of the DSM-IV. Criterion A2, which is shown to be non-predictive of a PTSD diagnosis (Osei-Bonsu et al., 2012) was not assessed using a scale (rather an individual item); hence 49 of 308 participants not reporting initial feelings of fear, helplessness or horror in response to their worst trauma were included in the current study. However, future studies would benefit by assessing criterion A2 with a normed scale, given its predictive relation with PTSD severity (Osei-Bonsu et al., 2012). Given variance of the trajectory of PTSD symptoms by type of traumatic events experienced (e.g., intentional versus non-intentional) (Santiago et al., 2013) and the lack of PTSD symptom differentiation by traumatic event type in the current study; this could be an area of future research. Of note is

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that a large portion of the current sample endorsed death of a family member/close friend as the worst trauma consistent with this event type being one of the most prevalent traumatic events (Luz et al., 2011). However, this restricts generalizability of results to studies on symptoms in response to other trauma types. Lastly, the trauma type of death of family member/close friend does not ask for direct/indirect exposure or other details to ascertain if it meets criterion A1. Given the controversy regarding the definition of criterion A1 events (Kilpatrick, Resnick, & Acierno, 2009), this lack of information may be a potential confound in the current study possibly influencing PTSD’s prevalence in the study sample. Use of self-report measures of PTSD and BIS/BAS could not only lead to response biases, but also difficulty in ascertaining the nature of traumatic exposure and differentiation of PTSD from other emotional reactions to loss of a person. Future studies with clinician-administered measures would strengthen the validity of results. With the possibility of the influence of several covariates on the current study results, future studies could also address the aforementioned in a path analyses model. The present study validates relations between PTSD and BIS using structural modeling techniques. Results strengthen PTSD’s association with anxiety symptoms, and indicate some direction toward exploring the source of PTSD’s common variance with impulsivity (BAS). Lastly, it emphasizes the central role of avoidance when explaining the relationship between BIS/BAS functioning and PTSD’s dysphoria. References Aidman, E. V., & Kollaras-Mitsinikos, L. (2006). Personality dispositions in the prediction of posttraumatic stress reactions. Psychological Reports, 99, 569–580. http://dx.doi.org/10.2466/PR0.99.2.569-580 Aluja, A., & Blanch, A. (2011). 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