Substance use patterns and mental health comorbidities in youth with a history of depression or suicidality: Findings from TX-YDSRN

Background: There is a robust relationship between depression and substance use in youth, with higher levels of substance use associated with greater depressive symptomatology. However, previous research has examined individual substances, without consideration of psychiatric comorbidities. Here, we investigate patterns of substance use among depressed and/or suicidal youth within the context of psychiatric comorbidities. Methods: 945 youth with depression and/or suicidality from the Texas Youth Depression and Suicide Research Network (TX-YDSRN) were assessed for current use of alcohol, nicotine, cannabis, and other drugs and comorbid psychiatric diagnoses. We used latent class analysis to identify patterns of past-year substance use, then examined if demographics or psychiatric disorders predicted class membership. Results: We identified three patterns of substance use: non-use (63.4 %), moderate likelihood of using alcohol, nicotine and cannabis (23.8 %), and high likelihood of using all substances (12.7 %). Compared to non-users, individuals in the moderate and high likelihood classes were more likely to be older. Individuals in the high likelihood class were more likely to have a substance use disorder, ADHD, and higher suicidality scores. Limitations: We cannot ascertain the causal or temporal ordering of substance use and psychiatric diagnoses due to the cross-sectional nature of the study. Conclusions: Using a brief, self-report measure of substance use, we identified three classes of substance users differing in probability of past-year use, which were predicted by older age and some psychiatric comorbidities. While research on universal screening of substance use in youth remains limited, we discuss who may benefit from such screening among depressed youth.