A prospective study of the impact of smoking on outcomes in bipolar and schizoaffective disorder.

BACKGROUND: Tobacco smoking is more prevalent among people with mental illnesses, including bipolar disorder, than in the general community. Most data are cross-sectional, and there are no prospective trials examining the relationship of smoking to outcome in bipolar disorder. The impact of tobacco smoking on mental health outcomes was investigated in a 24-month, naturalistic, longitudinal study of 240 people with bipolar disorder or schizoaffective disorder.

METHOD: Participants were interviewed and data recorded by trained study clinicians at 9 interviews during the study period.

RESULTS: Comparisons were made between participants who smoked daily (n = 122) and the remaining study participants (n = 117). During the 24-month study period, the daily smokers had poorer scores on the Clinical Global Impressions-Depression (P = .034) and Clinical Global Impressions-Overall Bipolar (P = .026) scales and had lengthier stays in hospital (P = .012), compared with nonsmokers.

LIMITATIONS: Smoking status was determined by self-report. Nicotine dependence was not measured.

CONCLUSION: These findings suggest that smoking is associated with poorer mental health outcomes in bipolar and schizoaffective disorder.