Smoking increases the risk of developing mental disorders such as depression and schizophrenia, said specialists from the University of Bristol in the UK.
According to The Guardian, the researchers wanted to figure out if there is a connection between genes that promote smoking addiction and mental disorders.
“The 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 source noted. “As an example, 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 odds of developing depression than someone who had never smoked.”
The genetic predisposition to schizophrenia, as experts found, was less associated with a tendency to smoke, which suggests a causal relationship between habit and mental illness. However, scientists do not yet know which mechanisms are responsible for this.