OBJECTIVE: The authors' goal was to study the relationship between
smoking status and clinical characteristics in schizophrenic patients.
METHOD: Seventy-eight schizophrenic outpatients were assessed by a single
rater using the Brief Psychiatric Rating Scale (BPRS), the Abnormal
Involuntary Movement Scale, and the Simpson-Angus Scale for extrapyramidal
symptoms. Current smokers (N = 58) were compared with nonsmokers (N = 20)
on clinical variables by independent t tests and chi-square tests.
Differences in outcome variables were tested by multiple analysis of
covariance (ANCOVA) with smoking status and gender as factors and age,
neuroleptic dose, and caffeine consumption as covariates. RESULTS:
Seventy-four percent of patients were current smokers and reported a mean
of 19 cigarettes smoked per day. Compared to nonsmokers, current smokers
were significantly more likely to be men, to be younger, and to have had an
earlier age at onset and a greater number of previous hospitalizations.
Current smokers and nonsmokers received mean neuroleptic doses of 1160 and
542 mg/day (chlorpromazine equivalents); the difference was significant.
Current smokers also displayed significantly less parkinsonism and more
akathisia and had higher total scores on the BPRS. Overall multiple ANCOVA
demonstrated a significant main effect for smoking status but not gender or
the interaction between gender and smoking status. Univariate ANCOVAs
demonstrated a significant main effect of smoking status only for the
Simpson-Angus Scale score. CONCLUSIONS: Cigarette smokers receive
significantly higher neuroleptic doses, in part because of a
smoking-induced increase in neuroleptic metabolism. Smoking is also
associated with significant reduction in levels of parkinsonism. Smoking
status is a significant factor that should be considered in assessment of
neuroleptic dose requirements and neuroleptic side effects.