In research that turns on its head previous thinking about links between schizophrenia and smoking, scientists say they have found that cigarettes may be a causal factor in the development of psychosis.
After analyzing almost 15,000 tobacco users and 273,000 nonusers and their relative rates of psychosis — where patients can experience delusions, paranoia and hear voices in their heads — the researchers said cigarette smoking appears to increase risk.
"While it's 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," James MacCabe, a psychosis expert who co-led the research at King's College London's Institute of Psychiatry, told reporters.