Who is most at risk of suicide by drug overdose? Has that changed in recent years? Researchers at the National Institute on Drug Abuse analyzed data from 2001 to 2019 from the Centers for Disease Control and Prevention’s National Vital Statistics System to find out.
On the whole, they say, intentional overdose deaths have declined. But suicide rates increased in certain subgroups: young adults (aged 15-24 years), older adults (aged 75-84 years), and non-Hispanic Black women. Rates among women were “consistently higher” than those of men. The highest rates were observed in women aged 45 to 64 years.
Monday was the worst day, and the weekends had the lowest rates. The researchers say social factors, such as more social interactions on the weekend and reluctance about starting the workweek, could be factors.
Seasonally, the numbers ran true to the pattern seen in previous studies: The lowest rates occurred in December and highest in late spring and summer. Perhaps the “collective optimism” of the holiday season and social interactions exert protective effects against suicidality, the researchers suggest.
Factors also may include biological changes. In this study, the researchers found a positive linear relationship between daylength, which varies by latitude, and intentional overdose deaths for both sexes. Daylength is associated with mu opioid receptor (MOR) availability that might underlie seasonal variations in mood, they posit. MORs are the main target of opioid drugs; the researchers cite a study that found altered MOR expression in postmortem brains of suicide victims.
They note some limitations of their study, one being that, in 2019, 5% of overdose deaths had undetermined intent. Improving classifications of overdose deaths is needed, they say.
Moreover, the trends might have changed during the pandemic, as provisional mortality data indicate decreases in deaths by suicides, but also an approximate 30% increase in overall overdose deaths.
“This research underscores the importance of external support structures and environmental factors in determining a person’s suicide risk,” said Emily B. Einstein, PhD, chief of the National Institute on Drug Abuse’s Science Policy Branch and an author on the study. “The risk of intentional overdoses, and suicide risk in general, is not static. This is crucial for clinicians to keep in mind, as they may need to assess patients’ suicide risk frequently rather than at one point in time. It is also important for friends and family members of people who may be at an increased risk of suicide, and for those people themselves, so that they can be aware of the greatest periods of risk and seek help when needed.”
Han B, Compton WM, Einstein EB, et al. Intentional drug overdose deaths in the United States. Am J Psychiatry. doi:10.1176/appi.ajp.2021.21060604