แปลบทความวิจัย
Moreover, a schizophrenic smoker consumes more cigarettes each day and with a greater preference for unfiltered, high nicotine and high tar cigarettes than does a smoker in the general population. Schizophrenics also extract more nicotine per cigarette than do healthy smokers.
That cigarettes and nicotine hold a unique sway over schizophrenic individuals is suggested by comparisons with other psychiatric patients. Schizophrenic patients are more likely to smoke than patients diagnosed with other psychiatric conditions. These data stand in contrast to the use of other unprescribed drugs. Although alcohol and illicit drug use by schizophrenic outpatients are estimated at circa 50%, this is no higher than many other psychiatric populations. Individuals diagnosed with major depression, attention deficit hyperactivity disorder and post-traumatic stress disorder are also attracted to illicit drugs and alcohol at rates similar to schizophrenic patients.
Smoking behaviors and their effects in patients and healthy people should be different
As predicted by the SMH, there are differences between the responses of schizophrenic smokers and healthy smokers. Yet, the overall data are mixed, with some supporting the SMH and others contradicting the hypothesis.
Schizophrenic patients report that they smoke for many of the same reasons indicated by smokers in general. However, there are differences in the ratings of certain motivations. For example, schizophrenic patients highly rank the stimulant properties of cigarettes, suggesting they associate smoking with relief from schizophrenia symptoms or, more likely, from medication side effects.
Interestingly, two extensive studies on the motivation to smoke found that healthy controls more prominently cited increased social activity than schizophrenic smokers. This is surprising because a prominent symptom of the disease is asociality, and one would expect relief from asociality would be attractive to patients. Indeed, an experiment designed to assess the social influences of nicotine failed to support the SMH. Schizophrenic and healthy smokers were administered nicotine after 24 h abstinence from smoking. There were no group differences on social cognition or facial affect recognition. Moreover, there were no differences in subjective stress reports.
This is in contrast to the conclusions of other authors that smoking schizophrenics are more sensitive to acute nicotine abstinence. Upon finding abstinence-induced decrements in visuospatial working memory task only in the schizophrenic smokers, the authors concluded that patients experience greater cognitive declines than in non-patient smokers.
Other studies in this literature have used various measures of cognition to distinguish between schizophrenic and healthy smokers. Smoking in both groups has been reported to enhance some aspects of cognitive function, working memory and, especially, sustained attention to visual cues. However, patients who smoke may benefit more; for example, schizophrenic subjects had better information processing scores than healthy smokers on a selective attention task. A review of the cognition literature concluded that nicotine from smoking was effective in remediating many of the cognitive deficits accompanying schizophrenia whereas evidence for gains in cognitive performance in healthy smokers was more suspect.