Smoking Increases Risk Of Schizophrenia And Psychosis: Study

Overturning prevailing notion that psychotic people are more likely to smoke, a new meta-analysis claims that smoking could increase risk of psychosis.

Researchers at Kings College London (KCL) analyzed 61 observational studies that involved 15,000 smokers and 273,000 non-smokers. They found that 57 percent of the people in the studies who reported their first symptoms of psychosis were smokers. The prevailing notion is that antipsychotic medication can push people to smoke as it tends to counteract the side-effects of medication and even psychotic disorders like schizophrenia. The KCL study however suggests an opposite direction for the causality.

"While it is always hard to determine the direction of causality, our findings indicate that smoking should be taken seriously as a possible risk factor for developing psychosis, and not dismissed simply as a consequence of the illness," Dr. James MacCabe, senior lecturer at KCL said.

One hypothesis is that nicotine stimulates production of excess dopamine which is associated with conditions like schizophrenia.

"Longer-term studies are required to investigate the relationship between daily smoking, sporadic smoking, nicotine dependence and the development of psychotic disorders. In view of the clear benefits of smoking cessation programmes in this population every effort should be made to implement change in smoking habits in this group of patients," said Dr. Sameer Jauhar.