Why Do Schizophrenics Smoke Cigarettes?

For health care workers in psychiatric hospitals, it is no secret: one of the major issues confronting psychiatric facilities seeking to institute blanket no-smoking policies concerns chronic inpatients with schizophrenia. Patients with schizophrenia are almost always heavy cigarette smokers, given a choice. As Edward Lyon wrote in an analysis of studies and surveys performed throughout the 1990s: “Many patients in psychiatric hospitals would smoke two, three, or even four packs of cigarettes a day if an unlimited supply of cigarettes were available.”
Generally, the rate of inpatient smoking among schizophrenics is three to four times higher than the general smoking population. In one British study of 100 institutionalized schizophrenics cited by Lyon, 92% of the men and 82% of the women were smokers. Moreover, schizophrenics smoke more cigarettes per day than other smokers do, and they commonly smoke high-tar, unfiltered cigarettes — niche brands for heavy smokers used by only 1% of the total smoking population.
Australian research performed in 2001 found that because of high rates of smoking, “people with mental illness have 30% more heart disease and 30% more respiratory disorders,” according to Ann Crocker, now a professor of Clinical Psychiatry at McGill University.
Not only do an estimated 80% of schizophrenics smoke, compared to roughly 25% of the total adult population, psychiatric facilities report that depressives and those with anxiety disorders also smoke in great numbers.
The review of studies through 1999, undertaken by Lyon and published in Psychiatric Services, shows unequivocally that schizophrenic smokers are self-medicating to improve processing of auditory stimuli and to reduce many of the cognitive symptoms of the disease. “Neurobiological factors provide the strongest explanation for the link between smoking and schizophrenia,” Lyons writes, “because a direct neurochemical interaction can be demonstrated.”
Of particular interest is the interaction between nicotine and dopamine in the nucleus accumbens and prefrontal cortex. Several of the symptoms of schizophrenia appear to be associated with dopamine release in these brain areas. A 2005 German study concluded that nicotine improved cognitive functions related to attention and memory. “There is substantial evidence that nicotine could be used by patients with schizophrenia as a ‘self-medication’ to improve deficits in attention, cognition, and information processing and to reduce side effects of antipsychotic medication,” the German researchers concluded.
In addition, the process known as “sensory gating,” which lowers response levels to repeated auditory stimuli, so that a schizophrenic’s response to a second stimulus is greater than a normal person’s, is also impacted by cigarettes. Sensory gating may be involved in the auditory hallucinations common to schizophrenics. Receptors for nicotine are involved in sensory gating, and several studies have shown that sensory gating among schizophrenics is markedly improved after smoking.
There is an additional reason why smoking is an issue of importance for health professionals. According to Lyon, “Several studies have reported that smokers require higher levels of antipsychotics than nonsmokers. Smoking can lower the blood levels of some antipsychotics by as much as 50%…. For example, Ziedonis and associates found that the average antipsychotic dosage for smokers in their sample was 590 mg in chlorpromazine equivalents compared with 375 mg for nonsmokers.”
Smoking among inpatient psychiatric patients is not trivial. Neither is the decision to institute smoking bans in psychiatric hospitals, a move that is understandably unpopular with patients.
Lyon, E. (1999). A Review of the Effects of Nicotine on Schizophrenia and Antipsychotic Medications. Psychiatric Services, 50, 1346-1350.
Cattapan-Ludewig, K. (2005). Why do schizophrenic patients smoke? Nervenarzt, 76 (3), 287-294.
Mueser, K., Crocker, A., Frisman, L., Drake, R., Covell, N., & Essock, S. (2005). Conduct Disorder and Antisocial Personality Disorder in Persons With Severe Psychiatric and Substance Use Disorders Schizophrenia Bulletin, 32 (4), 626-636 DOI: 10.1093/schbul/sbj068
Adler, L., Hoffer, L. Wiser, A. (1993). Normalization of auditory physiology by cigarette smoking in schizophrenic patients. American Journal of Psychiatry, 150, 1856-1861.

Source: http://brainblogger.com/2009/07/03/why-do-schizophrenics-smoke-cigarettes/
3rd July 2009

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