Associations of Substance Use and Illicit Drug Use Behaviors with Suicide Ideation Among U.S. Adults

BACKGROUND: Substance use is a known risk factor for suicidal ideation. This study examined the relationship between types and timing of substance use and past-year suicidal ideation. METHODS: = 127,380). We developed a categorical variable to classify participants' illicit drug use into four groups: those who never used illicit drugs, those with lifetime use only, those who used one type of substance in the past year, and those who used more than one type of substance in the past year. Multivariable logistic regression models with age interaction terms were applied to examine the associations. RESULTS: Substance use was found to increase the risk of suicidal ideation; however, this association was weaker in younger adults (ages 18-34) compared to those aged 35 and older. Higher odds of suicidal ideation were observed among bisexual and lesbian/gay individuals, females, those receiving government assistance, residents of small metropolitan areas, and marijuana users. In contrast, Black and Hispanic participants exhibited lower adjusted odds. Other variables, including sexual identity, income, marijuana use, and government assistance, were included as covariates and were associated with suicidal ideation. CONCLUSIONS: Our observations highlighted a consistent positive association between substance use and suicidal ideation. However, based on our empirical findings, it is imperative for public health and medical practitioners to consider age and substance use together as important interactive factors when desiging interventions.