Smoking ‘important’ schizophrenia risk

Smoking should be considered an “important” risk factor for schizophrenia, a scientist has claimed.

Professor Boris Quednow, from the University Hospital of Psychiatry in Switzerland, led new research suggesting smoking increases the impact of schizophrenia genes.

Healthy smokers carrying the gene variants responded to an “acoustic stimuli” test in the same way as individuals suffering from the serious mental disorder. The effect also appeared to be stronger the more a person smoked.

The study involved more than 1,800 participants who underwent a simple test which involves listening to a sequence of similar clicks.

Brainwave measurements show that most people suppress other, irrelevant, stimuli while processing the sounds.

But patients with schizophrenia appear to lack this filtering mechanism. As a result, their brains are thought to be inundated with too much information.

Psychiatrically healthy people carrying variants of the gene TCF4 that increased the risk of schizophrenia also displayed poorer acoustic filtering, the study found. However, smoking appeared to amplify the effect, resulting in greater deficits.

The findings are published in the journal Proceedings of the National Academy of Sciences.