Investigating Associations of Substance Use and Dependence With Planned Versus Unplanned Suicide Attempt

The present analyses investigated substance use and dependence as correlates of past-year suicide attempt and of unplanned versus planned suicide attempt in a nationally representative sample.

Participants were 214,505 adults (52% female; 64% White, 12% Black, <1% Native American, <1% Pacific Islander, 6% Asian, 16% Hispanic, 2% multiracial) from the 2015-2019 National Surveys on Drug Use and Health. Four logistic regression models were constructed. Models 1 and 2 examined substance use and dependence, respectively, as correlates of suicide attempt. Models 3 and 4 evaluated whether substance use and dependence were related to suicide attempt in the absence of a plan.

In Models 1 and 2, higher cigarette smoking and marijuana use; any use of opioids, sedatives, and hallucinogens; and greater dependence on nicotine, alcohol, marijuana, and any illicit or prescription drug were associated with elevated risk for suicide attempt. Associations with cigarette smoking, sedative use, and dependence on nicotine, alcohol, and any illicit or prescription drug remained statistically significant in sensitivity analyses limited to individuals with suicidal ideation. In Models 3 and 4, substance use and dependence were unrelated to risk for unplanned (vs. planned) suicide attempt.

Although substance-related outcomes are consistently associated with suicide attempt, there was little evidence that substance use and dependence are related to risk for unplanned versus planned suicidal behavior.