A new study from King’s College London found that smoking increases the likelihood of psychosis for people who took to the habit.
Psychosis diagnosed patients are up to three times more likely to be from the smokers’ ranks, the study suggests. It is yet unclear what the relation between psychosis and smoking is without a causal relation being established.
The research published in the Lancet Psychiatry journal suggests that everyday smokers are not only more prone to cardiovascular disease and strokes, as well as cancer, but also to mental illness.
To reach the conclusion, the researchers looked at 61 studies conducted between 1980 and 2014 worldwide. A total of 15,000 smokers as well as 273,000 non-smokers were included in the studies.
Of these, a number had been diagnosed with schizophrenia or other psychotic illness. 57 percent of this group were found to be smokers. Also, smokers were more likely to be diagnosed with psychotic illnesses one year earlier than their non-smoking peers.
Doctor James MacCabe, researcher from the King College London stated:
“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”.
As to what exactly underpins this connection is still a matter of debate. Until recently, most hypotheses evolved around the need to find relief from distress, boredom or side-effects of the medication in smoking.
However, the troubling factor with these hypotheses is that smoking rates exist before psychosis is developed and they do not increase significantly after people are diagnosed.
Instead, the new study suggests, smoking may cause psychosis, particularly in the case of daily smokers. The association may be due to the dopamine release system.
As dopamine is responsible for controlling the pleasure and reward centers in the brain, excess dopamine that is a result of smoking may cause psychosis to develop.
Robin Murray, also of the King College London, explained that:
“Excess dopamine is the best biological explanation we have for psychotic illnesses such as schizophrenia. It is possible that nicotine exposure, by increasing the release of dopamine, causes psychosis to develop.”
More studies are necessary to understand the relationship between smoking and psychosis. The research team stated that the study is not exhaustive and so far does not establish any causal relation.
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