KUALA LUMPUR, Nov 6 – Cigarettes could increase the risk of mental health problems such as depression and schizophrenia, a new research indicates.
Previous research failed to distinguish whether smoking could be a factor in causing mental health problems or is simply a form of self-medication among those already living with poor mental health.
“What we found was that there was evidence of causal effects in both directions,” said Dr Robyn Wootton, the first author of the research, from the University of Bristol, according to The Guardian.
The research team focused on 378 genetic variants that have previously been linked to whether people start smoking, as well as 126 genetic variants the team found were linked to a higher score for lifetime smoking – a measure encompassing how heavily people smoked, for how long, and if they quit.
The team then employed two separate genetic databases, one including thousands of individuals with schizophrenia and the other including thousands of individuals with major depression, in an aim to find out whether the risk of having such conditions was linked to the genetic variants for smoking.
The results reveal that both starting smoking and higher levels of smoking are linked to a greater risk of both depression and schizophrenia.
For instance, an individual who smoked 20 cigarettes a day for 15 years but then did not smoke for 17 years had more than twice the odds of developing schizophrenia and almost twice the chances of being diagnosed with depression than someone who had never smoked.
“Of course, if [smoking] is also making the risk of mental illness worse then we should be helping individuals who have existing mental health problems to stop as well,” Dr Wootton was quoted saying.
She added that it is important to accurately analyse exactly how smoking might increase the risk of schizophrenia and depression, but hypothesised that nicotine influences pathways in the brain linked to mental health problems.
That could be important, she added, since nicotine is also found in electronic cigarettes.
“While the physical harms of smoking are well known, this research points to the mental health risks of using tobacco. This risk should be communicated widely but particularly to school-age children who might be tempted to try smoking,” stated Dr Ian Hamilton, an expert in addiction and mental health from the University of York.