serve persons experiencing mood problems; however, they may not generalise to the rest of the NESARC sample or to the national population. Second, the sample did not include persons who had completed suicide attempts. Using the US rate of 11.1 per 100 000 population per year,32 the wave 1 sample of 43 093 could be expected to include about 14 persons with completed suicides before wave 2 (95% CI 6.8 to 21.6), introducing a non-trivial, although likely small, selection bias. Third, the present study did not assess the effects of medical conditions that are possibly causally related, albeit in different directions, to smoking and to SRO. Fourth, self-reported smoking information was not biologically validated. Fifth, the NESARC did not obtain information from adolescents, a subgroup with a known high risk for SRO.2 Finally, in exploratory unadjusted analyses, predictive effects of current smoking were observed across the individual SRO, whereas past smoking predicted want to die and suicidal ideation but not suicide attempt. Validation and articulation of these preliminary observations need to be accomplished in future work.
