Smoking may play a role in developing psychotic illnesses like schizophrenia, say scientists. Researchers have published an analysis in the Lancet Psychiatry journal, showing that people with psychosis are three times more likely to smoke than their counterparts who do not have the disease.

The researchers conducted the analysis of 61 studies that provided them access to data on 15,000 smokers and 2, 73,000 nonsmokers. It was found that smokers accounted for 57% of people first diagnosed with psychosis. The researchers also determined that development of psychotic illness in smokers took place a year earlier than non-smokers.

Experts say that smoking might be providing relief to psychosis sufferers from boredom or distress. If the hypothesis is true then smoking rates are likely to increase only after people develop psychosis. Smoking should be seen potentially dangerous to trigger psychosis.

“As a psychiatrist, it’s always something you think about, because you always see patients with psychotic illnesses smoking. People always generally put it down to self-medication”, said Sameer Jauhar, a psychiatric researcher at King’s College London, noticed the relationship.

The researchers also found that people with schizophrenia took up smoking habit at younger age than other smokers, before psychotic symptoms appeared.

Nicotine is known to stimulate production of the brain chemical dopamine, which plays a crucial role in controlling the brain's reward and pleasure centers. Patients with psychosis were seen to have increased levels of dopamine. Medications are given to schizophrenia patients to reduce dopamine activity.