Effects of smoking during antipsychotic withdrawal in patients with chronic schizophrenia

A number of studies have shown that patients with schizophrenia smoke mon t han other psychiatric patients and more than the general population. Also, medicated schizophrenics who smoke present more positive symptoms of schizo phrenia than non-smokers. The objective of the present study was to assess the effect of smoking on ratings of psychopathology for 30 days following d iscontinuation of antipsychotic medication. The subjects were 101 treatment -resistant patients with schizophrenia who had been admitted to the inpatie nt service of Neuroscience Research Hospital (NRH), National Institute of M ental Health, between 1982 and 1994 to undergo studies involving discontinu ation of antipsychotic medication. Patients were rated independently on a d aily basis on the 212-item Psychiatric Symptom Assessment Scale (PSAS), an extended version of the Brief Psychiatric Rating Scale (BPRS). At baseline, ratings for Verbal Positive, Paranoia and Loss of Function were higher in smokers (n=65) than nonsmokers (n=36), but a statistically significant diff erence was observed only for the Verbal Positive cluster. Analysis by gende r revealed that male non-smokers had the lowest psychopathology ratings at baseline. There were no differences in Anxiety/depression, Behavior Positiv e, Deficit Symptoms or Mannerisms (a measure for abnormal involuntary movem ents). Following medication discontinuation, repeated-measure analysis demo nstrated a 'time' effect for all the variables studied and a 'group' (smoke rs vs. Iron-smokers) effect for Verbal Positive. Paranoia, and Loss of Func tion. Post-hoc comparisons at individual time points showed significantly h igher ratings for smokers at week 1 for Paranoia. No differences were obser ved at later time points. In conclusion, at baseline, smokers had more posi tive symptoms and were apparently more functionally impaired than non-smoke rs. This difference was no longer evident after a 30 day medication discont inuation period, (C) 2000 Elsevier Science B.V. All rights reserved.