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NIDA. (2005, May 1). Depression Elevates Suicide Risk in Substance-Abusing Adolescents. Retrieved from

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May 01, 2005

A recent NIDA-funded study highlights the need for substance abuse counselors to be aware of depression and suicide risk in their adolescent patients. Drs. Thomas Kelly, Duncan Clark, and colleagues at the University of Pittsburgh School of Medicine identified 85 suicide attempters in a series of 503 substance-abusing teenagers studied from 1991 to 2000. Most of the teenagers abused alcohol (88 percent) and marijuana (80 percent). A large majority—87 percent—of those who had attempted suicide were diagnosed with major depression using the Diagnostic and Statistical Manual, 4th Edition (DSM-IV) criteria. Among substance-abusing teens who did not attempt suicide, major depression was diagnosed in only 40 percent. Girls were three times more likely to have attempted suicide than boys. Among the attempters, one-third of girls and one-tenth of boys reported multiple attempts—a finding consistent with general patterns of suicidal behaviors.

"Clinicians who work with adolescent substance abusers may not automatically think about suicidal behavior as something to watch for in their clients, but it's definitely a concern—especially for youth with cooccurring psychiatric disorders," says Dr. Lynda Erinoff of NIDA's Division of Epidemiology, Services and Prevention Research. There is an association between substance abuse, co-occurring psychiatric disorders, and suicidal behavior in adults and adolescents, but Dr. Erinoff explains that it's difficult to establish causal factors and sequencing of these problems.

Dr. Clark and his colleagues are pursuing another avenue of research that may provide clinicians with a biological marker to help assess patients' risk of suicidal behavior. In a recent prospective study, Dr. Clark found that depression and low blood levels of tryptophan—an amino acid found in protein-rich foods such as turkey and milk—were associated with increased suicide risk in adolescents who abused alcohol. Other studies have suggested that depleted tryptophan is related to depression and impulsivity, which seem to increase the risk for suicidal behavior. If additional studies corroborate the predictive value of this potential biological marker, clinicians could have a blood test to augment their behavioral assessment that a patient may be at risk for attempting suicide.


  • Kelly, T.M.; Cornelius, J.R.; and Clark, D.B. Psychiatric disorders and attempted suicide among adolescents with substance use disorders. Drug and Alcohol Dependence 73(1):87-97, 2004. [Abstract]
  • Clark, D.B. Serum tryptophan ratio and suicidal behavior in adolescents: a prospective study. Psychiatry Research 119(3):199-204, 2003. [Abstract]