The impact of smoking cessation on schizophrenia and major depression

This review sought to determine whether quitting smoking behaviour places people with a history of schizophrenia or major depression at risk of worsening symptoms or relapse.

Literature searches of Embase, MEDLINE, the Cochrane Library and PsycINFO.

Six studies involving 735 people diagnosed with schizophrenia, schizoaffective disorder or psychotic disorder did not find significant change in mental health status after quitting smoking. Five out of six studies involving 1,293 people with a history of major depression did not find an increased risk of depression with abstinence from smoking, while one study did. Two of these studies found an improvement in depressive symptoms among quitters.

There is no published evidence to support the hypothesis that quitting smoking is harmful to the mental health of people with schizophrenia. Smoking cessation does not appear to place smokers with a history of major depression at increased risk of worsening symptoms nor relapse, and may even improve their mood. Psychiatrists and other mental health professionals should provide their patients with the same level of support to quit smoking that is given to the rest of the population.