The prevalence of smoking in patients with psychosis is high, which can be explained due to the symptom-relieving effects of smoking. The objective of this study is to evaluate smoking behavior in patients with psychosis and the subsequent quality of life.

This prospective cohort study included a total of 1,094 patients aged 16-50 years with non-affective psychosis, along with 1,047 unaffected siblings and 579 healthy controls. The researchers assessed the smoking status and the number of cigarettes per day at baseline. The primary outcome of the study was symptom frequency evaluated by Community Assessment of Psychotic Experience (CAPE) and quality of life examined by WHO Quality of Life (WHOQOL).

Out of 1,094 patients with non-affective psychosis, 729 (67%) smoked (mean 17.5 cigarettes a day), as compared with 401 unaffected siblings (38%) and 145 healthy controls (25%). Further analysis showed that smoking in patients and siblings was associated with more positive symptoms, negative symptoms, and depressive symptoms, along with a lower quality of life than non-smokers. However, smoking cessation was not associated with changes in symptoms or quality of life.

The research concluded that self-medication with smoking was not associated with an improvement in symptoms or quality of life in patients with non-affective psychosis.