Risk Factors for Drug Overdose Identified

Researchers from McLean Hospital call for greater efforts "to address this growing public health problem."

July 12, 2007

Laura Neves
Public Affairs

Belmont, MA - The best predictor of whether someone will overdose after detoxification from drugs or alcohol is if he or she has done so previously, says a study lead by researchers at Harvard-affiliated McLean Hospital.

    The paper, published in the July 10 issue of the journal Drug and Alcohol Dependence (abstract), found that 17 percent of a study sample of 470 adults in a Boston detoxification program had overdosed within two years of discharge, while 27 percent of those with problem opioid use overdosed in the two-year follow-up period.

    Those most likely to have an overdose, in the follow-up period were those who had previously overdosed, says study author James D. Wines Jr., MD, MPH, of McLean Hospital's Alcohol and Drug Abuse Research Center.

    "There is a national epidemic of drug poisoning deaths, but we do not have a very good handle in terms of who these people are," Wines says. "This study may help us better identify those individuals at greatest risk."

    In his study, Wines found that the most likely to overdose are individuals who have overdosed before, as well as those with recent symptoms of depression.

    Of the 470 subjects, 6 percent suffered their first overdose during the follow-up period after detoxification. Of those with opioid problems, 11 percent experienced their first overdose during a two-year period after receiving treatment. The study tracked self-reported, non-fatal overdoses requiring emergency medical care.

    Thirty-one percent of all subjects, and 42 percent of those with problem opioid use, had a lifetime history of overdose prior to admission, and Wines says those figures might be on the low side, since many overdoses are not treated medically.

    Those with prior histories of overdose were six times more likely to overdose again, the study found.    

    "The findings underscore both the high prevalence of non-fatal overdoses among detoxification patients, especially opioid users, and the potency of prior overdose as a risk factor for future drug overdose," says Wines.

    Wines hopes that the findings will prompt those in the field of drug and alcohol abuse treatment to screen patients for prior overdose, depressive symptoms and other factors that may play a role in leading to overdose.

    Overdose "is a very prevalent event, a potentially life-threatening event and an event that is grossly understudied," he says. "Surveillance systems indicate that fatal overdose is increasing. We need to marshal efforts on a variety of levels to address this growing public health problem."

    According to national statistics, in 2004 there were 30,308 fatal poisonings and 857,687 non-fatal poisonings. Poisonings were the second leading cause of injury death overall. United States. Such poisonings include overdoses on illicit drugs, alcohol and medications.

    Wines speculates that the increased incidence of overdosing might in part be due to the heightened use and misuse of prescription pain medications as well as the growing misuse of prescription pain relievers by young people.

    "Another interesting finding of our study is the link between depressive symptoms and increased risk of overdose," says Wines. "A critical next step will be to distinguish between unintentional overdoses and suicide attempts. In any case, since depressive symptoms are modifiable, effectively treating depression may prevent overdose in some individuals."

    Curiously, although prior overdose, regardless of intent, was a risk factor for future overdose, the paper notes that prior unintentional overdose was the strongest predictor of future overdose. However, the paper also concludes that there was some evidence indicating that some "accidental" overdoses may not be completely unintentional.

    The study was conducted in collaboration with researchers at the Boston University School of Medicine and Boston Medical Center and funded by the National Institute on Drug Abuse, the National Institute on Alcohol Abuse and Alcoholism, and the National Center for Research Resources.

U.S. News & World Report consistently ranks McLean Hospital the nation's top psychiatric hospital. McLean is an affiliate of Harvard Medical School and Massachusetts General Hospital, and a member of Partners HealthCare.

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