Associations between illicit drug use in early adulthood and mortality: Findings from a National Birth Cohort.

Illicit drug use is known to be associated with premature mortality. Whether exposure to socioeconomic disadvantage and mental health problems in childhood help to explain this association, is unclear. We analysed data from 11,250 participants in the 1970 British Birth Cohort study. At 10-years of age, socioeconomic disadvantage (parental socioeconomic position, material disadvantage, family disruption) and mental health problems with antisocial behaviour, attention, and anxiety were reported by mothers and teachers. At 30-years of age, study members provided information on their illicit drug use, exposure to socioeconomic disadvantage and mental health problems. At 30-years, 19.2% of participants had used an illicit drug in the past year. Mortality was elevated for eight of the twelve drugs assessed. Family disruption, maternal, and teacher assessments of antisocial behaviour at 10-years were associated with illicit drug use at 30-years. There was, however, very little change in these associations when exposure to childhood socioeconomic disadvantage (% change in hazard ratios [HR] 0-10%) or mental health problems (0.4-11.9%) were added to the sex-adjusted model. Adding exposure to socioeconomic disadvantage (0.8-38.9%) and mental health problems (31.7-74.1%) in adulthood to the sex-adjusted model resulted in marked attenuation in HRs for all drugs. These findings imply that interventions which provide opportunities for education, employment and access to effective mental health treatments in early adulthood may help to reduce mortality among drug users.