While the link between suicide and substance use is complicated, often changing with age, gender, and race, a new study of hundreds of suicidal emergency department (ED) patients shows that the use of cocaine and alcohol together is strongly linked to suicide risk across the board.
“One unexpected finding was that, when examined independently, alcohol use had no significant association and cocaine use had a borderline significant association,” wrote authors of the study in the journal Crisis. “However, reporting both alcohol misuse and cocaine use was significantly associated with a future suicide attempt.”
The team, led by Sarah Arias of Alpert Medical School at Brown University, looked at 874 men and women who checked into one of eight emergency departments around the country between 2010 and 2012. The patients were participants in the Emergency Department Safety Assessment and Follow-up Evaluation study, led by the University of Massachusetts Medical School.
Individuals included in the research had received standard care and either had a recent suicide attempt or were having suicidal thoughts at the time of the initial ED visit. Researchers gathered demographic and substance use information from the participants and then followed them for a full year afterward.
The key outcome in the new study was whether these individuals attempted suicide in the year following the ED visit. Of the 874 people, 195 people did at least once.
The researchers found that while people in the study misused many different substances, including marijuana, prescription painkillers, tranquilizers, and stimulants, only cocaine and alcohol appeared to have a significant association with suicide risk.
Among all of the patients, 298 misused alcohol, 72 were using cocaine and 41 were using both. Specifically, of those using both, the chance of attempting suicide again was 2.4 times greater than those who did not.
The findings also showed that substance misuse was less likely an indicator of suicide risk among whites and women. Older people, however, showed a stronger link between substance misuse and suicide.
Women are not less likely to be suicidal, the researchers note. In fact, they are more likely than men to attempt suicide. But the findings show that substance misuse is less likely to be a factor among women.
“These disparate findings emphasize the complex interaction of sex, substance use, and suicide attempts,” Arias and her co-authors wrote. “They also suggest women may be differentially at risk depending on whether they report substance use or past suicide attempts.”
The study does not confirm whether or not substance abuse causes suicidal behavior. It only reports associations. But Arias said she hopes the data will help better explain how misuse of particular substances, among particular patients, may affect their risk of suicide.
“It’s not a clear-cut, straightforward association,” Arias said. “Even though substance use is often touted as a very strong predictor of suicidal intentions and behaviors, when we look at individual substances we’re seeing that there’s not that consistency in the future association with behavior.”
“We’re on our way to trying to identify factors that can be used to better assess and identify people who are at risk for suicide, and ultimately I think this is a step in the right direction to get a better picture,” she said. “Patients who have potentially comorbid alcohol and cocaine use may be at a higher risk. Findings like these can be useful for informing suicide risk assessment.”