That got me reading about smoking and mental illness and I came across this. It's about schizoaffective and bipolar though.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4423166/

"A recent prospective and naturalistic study over 24 months examined the effect of tobacco smoking on mental health outcomes in 239 patients with schizo-affective and bipolar disorder,11) and found that in both schizoaffective and bipolar disorder, daily smokers had poorer prognosis in terms of depression and overall bipolar symptomatology (assessed using the Clinical Global Impressions — Depression and Clinical Global Impressions — Overall Bipolar scales) and longer stays in hospital compared with non-smokers."