A new study conducted by scientists at King's College London (KCL) has found that cigarette smoking could potentially increase the likelihood of an individual to develop schizophrenia.

It has long been known that people suffering from schizophrenia have a higher rate of smoking compared to those that do not have the mental disorder, but it remains uncertain as to why it occurs.

In a study published in the journal The Lancet Psychiatry, psychosis expert James MacCabe and his colleagues at KCL's Institute of Psychiatry examined data from 61 observational studies from different parts of the world. The studies were conducted from 1980 to 2014 and involved around 15,000 tobacco smokers and more than 273,000 non-smokers.

The researchers discovered that 57 percent of participants who experienced the first episode of psychosis were tobacco users.

People who experienced the onset of psychosis were shown to be three times more likely to be tobacco smokers than those that belonged to the control groups.

The study also showed that participants who smoked daily developed illnesses related to psychosis a year earlier compared to non-smokers.

Robin Murray, a professor at KCL and co-author of the study, explained that activity in the dopamine system of the brain could provide a connection between psychosis and smoking.

He said that an excess production of dopamine brought on by exposure with nicotine is the most concrete biological explanation as to why psychotic illnesses occur in people.

Earlier studies have suggested that psychosis is also linked to the use of cannabis, but it has been debated whether assertion is casual or whether it is actually caused by shared genes that predispose individuals to both schizophrenia and cannabis use.

MacCabe said the new findings show that tobacco could be the more likely culprit and not cannabis since users of the drug often combine the substance with tobacco.

The researchers believe that genes for psychosis could overlap with those pertaining to cigarette smoking, but further studies are required to explore any potential connections.

Schizophrenia is a serious psychiatric ailment that currently affects one in every 100 people often at the beginning of early adulthood. Some of the most common symptoms of the disorder include disruptions in perception and thinking, which could lead to psychotic experiences for the patient.

Photo: Curran Kelleher | Flickr