Psychotic symptoms and smoking in 44 countries

Objective To assess the association between psychotic symptoms and smoking among community‐dwelling adults in 44 countries. Method 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. Results 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. Conclusions 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.