Patterns of Substance Use Associated with Suicidal Ideation Among Texas College Students

Purpose. Suicide is the second leading cause of death among college students. Substance use is associated with an increased risk of suicidal attitudes and behaviors, but most of this research has focused on alcohol use and has not addressed individual variability in substance use during the college years. The purpose of this study is to understand how individual patterns of substance use are associated with suicidal ideation among Texas college students.

Methods. Data are from the 2013 Texas Survey of Substance Use among College Students (N=10,510; 60% female, 85% White), a multi-stage cluster designed study representing undergraduates ages 18 to 26 attending public and private universities, colleges, and community colleges across the state of Texas. The outcome of interest was past year suicidal ideation. Substance use variables included past month use of alcohol (any, binge, and drunkenness) and past year use of tobacco, marijuana, cocaine, stimulants, sedatives, hallucinogens, heroin and other opiates, inhalants, and MDMA. The research question was answered using latent class analysis (LCA) with a distal outcome; analyses were run in SAS 9.4 using PROC LCA and the %LCA_distal macro.

Results. Over six percent of students thought about committing suicide in the past year. Tests of 1-9 classes confirmed that the 5 class solution was the best fit for the data: 1) Abstaining (40%), 2) Alcohol Use (17%), 3) Recreational Substance Use (31%), 4) Illicit Drug Use (3%), and 5) Heavy Substance Use (9%). Gender, race/ethnicity, GPA, and type of college (2 year vs. 4 year) were associated with class membership (all p<0.001). Past year suicidal ideation was higher (p<0.001) among individuals in the Heavy Substance Use class (15%) and the Illicit Drug Use class (15%) compared with individuals in the Recreational Substance Use (3%), Alcohol Use (5%), and Abstaining (5%) classes.

Conclusions. Results demonstrate the heterogeneity in substance use among college students as well as the differential risk of suicidal ideation depending on the pattern of recent substance use. While most of the focus on the link between substance use and suicidality has been on the connection between alcohol use and suicide, use of illicit drugs other than marijuana is a clear risk factor for suicidal ideation among college students.