Research finding · December 2025
Autopsy information can help distinguish deaths by accidental overdose from suicides
Understanding how and why deaths are classified as suicide is essential for accurate public health surveillance and effective prevention. Yet determining intentionality in overdose deaths is uniquely challenging as medications with different lethality potential can appear together, scene information may be limited, and medical examiners vary in how they classify ambiguous cases. In many states, large proportions of opioid-related deaths are labeled as “undetermined intent,” meaning it is unclear whether the death was accidental or intentional. Because overdose deaths and suicide often overlap, this uncertainty can lead to significant undercounting of suicide deaths. Improving how we identify probable suicides within this group could help states better understand the true burden of suicide and lead to allocating prevention resources more effectively, and ensuring families receive clearer information.
With support from AFSP, Dr. Paul Nestadt analyzed more than 10,000 opioid-related overdose deaths in Maryland between 2016 and 2020 to see whether information already available in standard autopsies, such as toxicology results and basic demographic data, could help identify suicides that may have been misclassified. Using cases that had been clearly labeled as either accidental or suicide, the researchers built a statistical model that learned to distinguish between the two. Along with other factors, certain substances were more common in suicides (including antidepressants, oxycodone, benzodiazepines, neuroleptics, and acetaminophen), while others (especially fentanyl, cocaine, and morphine) were far more common in accidental overdoses. When the model was applied to the large number of cases labeled as “undetermined,” it identified 58 additional deaths likely to be suicides, representing a 43% increase in suicide cases within this population. Although this does not replace the nuanced judgment of medical examiners, the findings show that routinely collected autopsy information can help flag cases that may warrant further review. Over time, this approach, especially when paired with additional clinical information, could strengthen surveillance systems and provide a more accurate picture of suicide within the overdose crisis.
Citation: Flores, J. P., Desjardins, M. M., Kitchen, C., Belouali, A., Kharrazi, H., Wilcox, H. C., & Nestadt, P. S. (2025). Use of Vital Records to Improve Identification of Suicide as Manner of Death for Opioid-Related Fatalities. Crisis, 10.1027/0227-5910/a001033. Advance online publication. https://doi.org/10.1027/0227-5910/a001033
This finding comes from an AFSP-funded study — see the grant below ↓
