This study investigated the interplay between smoking behavior, genetic predisposition to psychiatric disorders, and psychotic experiences using data from the UK Biobank. They found that smoking status, maternal smoking, and smoking intensity were associated with psychotic experiences. These associations were attenuated but remained significant after adjusting for psychiatric disorder diagnoses and polygenic risk scores (PRSs) for schizophrenia, bipolar disorder, major depression, and ADHD. Gene-environment interaction analyses revealed that the effects of PRSs for depression and ADHD on delusions were significantly greater in current smokers compared to never smokers. The findings suggest independent and synergistic effects of genetic risk and smoking on specific types of psychotic experiences.

Judit García-González, Julia Ramírez, David M. Howard, Caroline H. Brennan, Patricia B. Munroe, Robert Keers