The strongest associations between severe psychotic illness and substance use were seen with cigarette use. This is notable because most of the mortality seen in severe psychiatric illness is due to smoking related disorders. Also, it appears that recent public health efforts that have successfully decreased smoking in the general population have not been effective in individuals with severe psychotic disorder. Specifically, the decrease in smoking among individuals under age 30 that has been seen among the general population 32 and is present in the controls in this dataset does not extend to cases: the OR of smoking daily for a month or more is 8.2 among individuals younger than 30, which is significantly higher than the OR of 5.2 among individuals age 30-49, and the OR of 3.9 among individuals age 50 or older (interaction p=4.5 × 10−5). Given that (1) early mortality in cases is largely due to cardiovascular and pulmonary disease, and (2) many psychotropic medications used to treat psychotic symptoms have severe metabolic side effects that increase the risk of diabetes and cardiovascular disease, it is
