The Findings: Drug Use as Self-Medication

The paper found that the link between substance use and mental health existed even at low levels of drug and alcohol use. Dr. Tervo-Clemmens said that adolescents with low levels of substance use may be self-medicating and that their relatively modest substance use was not likely to be causing the underlying mental health challenges.

But the research also found that the most frequent and intensive users of the substances experienced the most severe mental health symptoms. In these instances, Dr. Tervo-Clemmens said, the adolescents may be worsening their symptoms even as they use substances to self-medicate.

Specifically, the study found that daily or near-daily use — but not weekly or monthly use — of substances was linked to a moderate increase in symptoms. Researchers described the connection as “dose dependent,” because the level of use was linked to the intensity of symptoms.

Background: Two Strong Data Sets

The strength of the study came from its use of two data sets that yielded similar findings.

One sample used survey data from 15,600 Massachusetts high school students with a median age of around 16. The second sample drew on similarly self-reported data from 17,000 respondents to the national Youth Risk Behavior Survey.

In both groups, the study’s authors noted, “alcohol, cannabis and nicotine use each had significant, moderate dose-dependent associations with worse psychiatric symptoms, including suicidal thoughts.”

Another key finding was that the link was present between multiple symptoms and between multiple substances. “It’s not just cannabis, it’s not just alcohol, it’s not just nicotine,” Dr. Tervo-Clemmens said. “It seems to be no matter the substance.”

What’s New: A Generational Change

Compared with prior generations, today’s adolescents are experiencing more mental health symptoms but a declining use of drugs and alcohol. Binge-drinking and cigarette smoking, in particular, have fallen sharply, affecting a smaller portion of the adolescent population.

These broad trends may support the idea that asking teenagers about substance use could be a way to screen for mental health challenges, Dr. Tervo-Clemmens said. That’s because the group of regular substance users is smaller than it once was and may be more closely linked to individuals who are self-medicating or otherwise dealing with mental health challenges.