A longitudinal study of risk factors for incident drug use in adults: findings from a representative sample of the US population.

OBJECTIVE

To examine baseline mental disorders and other correlates among people who have not previously used drugs as potential risk factors for incident drug use at 3-years' follow-up.

METHOD: Data came from the National Epidemiologic Survey on Alcohol and Related Conditions (commonly referred to as the NESARC) Wave 2 (2004 to 2005; n = 34 653), a longitudinal nationally representative survey of mental illness in community-dwelling adults. The study group consisted of people who reported no history of any illicit drug use or prescription drug misuse at Wave 1 (2001 to 2002). Logistic regression analyses were used to compare people with first-episode drug use at Wave 2 (n = 1145) to those who remained abstinent (n = 25 790) across various Wave 1 correlates, including sociodemographic factors, mental disorders (including alcohol use disorders and nicotine dependence), childhood adversity, and family history of substance use disorders.

RESULTS

All measures of childhood adversity were associated with an increased risk of incident drug use, as were alcohol or drug problems in first-degree relatives. In models adjusted for childhood adversity and a family history of addiction, a pre-existing mood disorder (AOR 1.31; 95% CI 1.04 to 1.64), personality disorder (AOR 1.82; 95% CI 1.50 to 2.20), previous nicotine dependence (AOR 1.41; 95% CI 1.09 to 1.83), and alcohol abuse or dependence (AOR 1.96; 95% CI 1.48 to 2.60) were independently associated with new-onset drug use at follow-up.

CONCLUSIONS

Specific mental disorders independently increase the risk of progression to incident drug use among people who were previously abstinent. Early-life adversities and addiction in family members accounts for some, but not all, of this observed relation.