Nicotine:
Smoking
gun or magic
bullet?
R.T. Pivik, PhD
Editor, Journal of Psychiatry and Neuroscience, Ottawa, Ont.
Although humans have been using tobacco for centuries, the first scientific knowledge about nicotine the constituent thought to be responsible for our atdates from 170 years traction to tobacco products' ago, when nicotine was isolated from tobacco leaves.2 In the intervening years, much has been learned about nicotine, but this information is often overshadowed or confounded by the significant morbidity associated with tobacco use, particularly in the form of smoking.3 The article by Le Houezec in this issue ("Nicotine: abused substance and therapeutic agent," page 95) suggests that studying the effects of nicotine may provide a better understanding of brain neurochemistry and behaviour. These effects include the enhancement of attention and cognition that nicotine provides and the possible protective influences that nicotine has on some pathologic processes, such as Alzheimer's disease, Parkinson's disease and Tourette's syndrome."6 It is well documented that adults who suffer from psychiatric disorders, particularly schizophrenia and depression, have a significantly higher prevalence of smoking. There are clinically relevant reasons for this use, including the self-medicating and antidepressant effects of nicotine, its ability to reduce anxiety and the side effects of medication.7"1' These reasons are probably influenced, in turn, by other genetic and environmental factors mediating both the predisposition for and response to nicotine.12
It is recognized that smoking has
an
impact
on
pharmacologic treatment and symptomatic variability in adults with psychiatric disorders. It has an effect on neurotransmitters thought to be involved in major psychiatric disorders and increases the rate of drug metabolism. As well, abrupt cessation of smoking exacerbates symptoms of psychiatric disorders.89'3 It would therefore seem natural for physicians to pay attention to whether their patients smoke. Generally, however, they do not.7 Similarly, there is an obvious need to make smoking cessation programs available to patients with psychiatric disorders.9'10 The development of pharmacologic techniques that involve nicotine replacement (nicotine gum, transdermal patches and nasal spray) offer promise in this regard. These techniques also provide tools to evaluate the effect of nicotine and nicotinic receptors in both normal and disordered behaviour. Although investigations into the use of nicotine as a therapeutic agent are essential, according to Newhouse and Hughes,4 they are complicated by "a number of potential problems associated with chronic use, including cardiovascular and behavioral toxicity as well as possible development of tolerance" and "the potential for producing dependence." In order to identify whatever positive or reinforcing effects nicotine has on brain functioning and behaviour, it will be essential to isolate the effects of this substance from the effects of smoking and other forms of tobacco use and to better define the complex interactions of nicotine in the central nervous system.
Correspondence to: Dr. R.T. Pivik, Department of Psychiatry, Ottawa General Hospital, Room 4431, 501 Smyth Rd., Ottawa ON K I H 8L6; fax 613 739-9980;
[email protected] Medical subject headings: depressive disorder; nicotine; nootropic agents; Parkinson disease; pharmacokinetics; schizophrenia; smoking; substance dependence; tobacco use disorder; Tourette syndrome J Psychiatry Neurosci 1998;23(2):91-2. © 1998 Canadian Medical Association
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Future studies in the area of biological psychiatry must directly assess, or at the very least control for, cigarette smoking to determine whether nicotine has any influence on outcome measures. Only with a more concerted integration of this variable into research and treatment will it be possible to differentiate between the detrimental ("smoking gun") and beneficial ("magic bullet") effects of nicotine.
References 1.
US Department of Health and Human Services. The health con-
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sequences of smoking: nicotine addiction. A report of the Surgeon General. Washington: US Department of Health and Human Services, Public Health Services, Office on Smoking and Health. DHHS Publication No. (CDC) 88-8406; 1988. 2.
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10. Lerman C, Audrain J, Orleans CT, Boyd R, Gold K, Main D, et al. Investigation of mechanism linking depressed mood to nicotine dependence. Addict Behav 1996;21(1):9-19. 11. Worthington J, Fava M, Agustin C, Alpert J, Nierenberg AA, Pava JA, et al. Consumption of alcohol, nicotine, and caffeine among depressed outpatients. Psychosomatics 1996;37:518-22. 12. Gilbert DG, Gilbert BO. Personality, psychopathology and nicotine response as mediators of the genetics of smoking. Behav Genet 1995;25(2):133-47.
13. Greeman M, McClellan TA. Negative effects of a smoking ban on an inpatient psychiatry service. Hosp Community Psychiatry 1991;42(4):408-12.
Revue de psychiatrie et de neuroscience
Vol. 23, no 2, 1998
