Youths who survive self-poisoning continue to be at risk of suicide for years

Suicide is the third most common cause of death among American adolescents, and poisoning is the leading method of attempted suicide, according to the Centers for Disease Control and Prevention. Unlike more violent methods, survival following self-poisoning is common, providing an opportunity to prevent subsequent suicide. However, little progress has been made in suicide prevention in the past 50 years. In fact, hospital admission rates for suicidal ideation and attempts by American children have more than doubled in the past decade.

Researchers, led by Yaron Finkelstein, M.D., and David Juurlink, M.D., conducted a population-wide study in Ontario, Canada, to determine the risk of completed suicide in teenagers treated earlier for self-poisoning as well as the timing and risk factors associated with suicide.

Using health care databases hosted at the Institute for Clinical Evaluative Sciences (ICES) from January 2001 to December 2012, investigators identified all youths ages 10 to 19 years who were treated in emergency departments after a first intentional self-poisoning episode. Each youth was matched with 50 adolescents with no such history.

Researchers conducted the largest-ever study in pediatric medicine on suicide risk and followed 20,471 teens treated for self-poisoning and 1,023,751 without such history for up to 12 years or until they died.

The median age of teens discharged from the hospital after the first self-poisoning episode was 16, and 69% were female. Acetaminophen was the most common agent ingested, followed by antidepressants and nonsteroidal anti-inflammatory drugs.

Over the follow-up period, 248 patients in the self-poisoning group died, more than half by suicide. The risk of suicide in this group was more than 30 times higher than their peers in the general population. Importantly, suicide risk was durable over many years, and half of all suicides occurred more than three years after the first attempt.

Factors associated with suicide included recurrent self-poisoning episodes, being male and psychiatric care in the preceding year. Adolescents hospitalized for self-poisoning were also more likely to die from accidents than youths in the general population.

"Self-poisoning in adolescence is a strong predictor of suicide and premature death in the ensuing decade, and identifies a high-risk group for targeted prevention," said Dr. Finkelstein, staff physician, Divisions of Emergency Medicine and Clinical Pharmacology and Toxicology, The Hospital for Sick Children (SickKids), and an associate professor, University of Toronto. "Suicide risk is markedly increased for many years after the first hospital presentation, emphasizing the importance of sustained prevention efforts in this vulnerable population."