Psychotic symptoms and smoking in 44 countries

To assess the association between psychotic symptoms and smoking among community-dwelling adults in 44 countries.

Data from the World Health Survey (WHS) for 192 474 adults aged ≥18 years collected in 2002-2004 were analyzed. The Composite International Diagnostic Interview was used to identify four types of past 12-month psychotic symptoms. Smoking referred to current daily and non-daily smoking. Heavy smoking was defined as smoking ≥30 tobacco products/day.

The pooled age-sex-adjusted OR (95% CI) of psychotic symptoms (i.e., at least one psychotic symptom) for smoking was 1.35 (1.27-1.43). After adjustment for potential confounders, compared to those with no psychotic symptoms, the ORs (95% CIs) for smoking for 1, 2, and ≥3 psychotic symptoms were 1.20 (1.08-1.32), 1.25 (1.08-1.45), and 1.36 (1.13-1.64) respectively. Among daily smokers, psychotic symptoms were associated with heavy smoking (OR = 1.45, 95% CI = 1.10-1.92), and individuals who initiated daily smoking at ≤15 years of age were 1.22 (95% CI = 1.05-1.42) times more likely to have psychotic symptoms.

An increased awareness that psychotic symptoms are associated with smoking is important from a public health and clinical point of view. Future studies that investigate the underlying link between psychotic symptoms and smoking prospectively are warranted.