Background: Despite growing numbers of older-adult illicit drug users, research on this topic is rare. This study examined the relationship between marijuana and/or other illicit drug use and major depressive episode (MDE) and serious suicidal thoughts among those aged 50+ years in the USA.
Methods: The public use files of the 2008 to 2012 US National Survey on Drug Use and Health (NSDUH) provided data on 29,634 individuals aged 50+ years. Logistic regression analysis was used to test hypothesized associations between past-year marijuana and/or other illicit drug use and MDE and serious suicidal thoughts.
Results: Nearly 6% of the 50+ years age group reported past-year marijuana and/or other illicit drug use. Compared to non-users of any illicit drug, the odds of past-year MDE among those who used marijuana only, other illicit drugs only, and marijuana and other illicit drugs were 1.54 (95% CI = 1.17-2.03), 2.75 (95% CI = 1.75-4.33), and 2.12 (95% CI = 1.45-3.09), respectively. Those who used marijuana and other drugs also had higher odds (2.44, 95% CI = 1.58-3.77) of suicidal thoughts than non-users of any illicit drug. However, among users of any illicit drug, no difference was found among users of marijuana only, marijuana and other illicit drugs, and other illicit drugs only. Among marijuana users, marijuana use frequency was a significant correlate of suicidal thoughts only among those with MDE.
Conclusions: Health and mental health (MH) service providers should pay close attention to the potential reciprocal effects of marijuana and other illicit drug use and MDE and suicidal thoughts among late middle-aged and older adults.
Keywords: cannabis; depression; illicit drug; marijuana; older adults; suicidal ideation.