Smoking associated with ‘high risk’ of developing schizophrenia: study

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LONDON — Physical health isn’t the only thing to decline every time a smoker lights up a cigarette. A new study shows smokers are at an increased risk of developing schizophrenia.

Researchers examined 61 studies that involved 14,555 smokers and 273,162 non-smokers and found that nicotine exposure can lead to changes in the brain as it increases the release of dopamine, causing the development of psychosis.

The study found that 57 percent of people with psychosis were smokers when they experienced their first psychotic episode. It also found that daily smokers were twice as likely as developing schizophrenia compared to non-smokers.

For those diagnosed with schizophrenia, the study showed that the smokers developed the illness about a year earlier than non-smokers and that it was likely to develop at a younger age in smokers.

“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,” said the study’s co-author James MacCabe, a physician at King College’s Institute of Psychiatry, Psychology and Neuroscience.

The researchers stress that smoking does not cause schizophrenia but rather increases the risk of the development of the disorder.

“It has been known for some time that patients who have schizophrenia are more likely to be cigarette smokers than people who do not have schizophrenia,” said Dr. Michael Bloomfield, a clinical lecturer in psychiatry at University College London.

The authors of the study say more research is needed to establish a stronger relationship.