Injection drug use is associated with suicide attempts but not ideation or plans in a sample of adolescents with depressive symptoms

Objective: Based on the interpersonal theory of suicide, pain habituation that occurs with injection substance use may raise risk for a suicide attempt. The current study tested whether injection substance use, relative to painless routes of substance administration, was related to greater risk for suicide attempts. We also assessed whether this risk was specific to suicide attempts and not suicidal ideation or suicide plans.

Methods: Data on 2095 substance-using adolescents aged 12-17 who endorsed clinically significant depression symptoms and answered questions on suicidal thoughts and behavior were drawn from the 2004-2011 National Survey on Drug Use and Health, a nationally representative household survey. Logistic regression analyses were conducted to assess the associations between injection substance use and suicidal ideation, plans, and attempts.

Results: Injection substance use was associated with suicide attempts (OR = 3.02, 95% CI = 1.75-5.23) but not ideation or plans. These findings were not accounted for by sex, age, race/ethnicity, family income, abuse and dependence symptoms, and depression symptoms. Among ideators, injection substance use was associated with suicide attempts (OR = 2.92, 95% CI = 1.58-5.06), but not plans. Among suicide planners, injection substance use was associated with suicide attempts (OR = 5.16, 95% CI = 1.88-14.17).

Conclusion: Consistent with the interpersonal theory of suicide, adolescent injection drug use was associated with specific risk for suicide attempts but not ideation or planning. Hence, consideration of the manner in which adolescents use substances is important in evaluating suicide risk in this population.