Longitudinal data revealed that individuals with ADHD were at higher risk for all-cause and cause-specific premature death, which may increase depending on the number of psychiatric comorbidities.
“Improved understanding of the potential contributions by psychiatric comorbidity for associations between ADHD and premature death could substantially facilitate surveillance, intervention and prevention efforts,” Shihua Sun, MD, from the Karolinska Institutet in Stockholm, and colleagues wrote in JAMA Psychiatry.
Using Swedish national registers, researchers conducted a prospective cohort study of more than 2.6 million Swedish individuals, of whom 86,670 were diagnosed with ADHD during follow-up, to examine the all-cause and cause-specific mortality risks in ADHD as well as the potential role of psychiatric comorbidities.
Psychiatric comorbidities were categorized into early-onset disorders — consisting of autism spectrum disorders, intellectual disability and conduct disorders — and later-onset disorders — consisting of eating disorders, substance use disorders, depressive disorders, bipolar disorders, anxiety disorders, schizophrenia spectrum disorders and personality disorders.
Over a mean follow-up of 11.1 years, 424 people with ADHD and 6,231 without died, resulting in mortality rates of 11.57 and 2.16 per 10,000 person-years.
Sun and colleagues reported that ADHD was associated with an increased risk for premature death in adulthood (HR = 4.64; 95% CI, 4.11-5.25) compared with childhood (HR = 1.41; 95% CI, 0.97-2.04). This risk for premature death increased with the number of psychiatric comorbidities present (HR for individuals with only ADHD = 1.41 [95% CI, 1.01-1.97] vs. HR for those with 4 or more comorbidities = 25.22 [95% CI, 19.6-32.46]), the results showed.
After adjusting for early-onset psychiatric comorbidity, the link between ADHD and risk for death due to natural causes was no longer statistically significant in adulthood.
However, after adjusting for later-onset psychiatric disorders, the link remained statistically significant for death caused by unintentional injury (HR = 2.14; 95% CI, 1.71-2.68) or other external causes (HR = 1.75; 95% CI, 1.23-2.48). When analyzing specific later-onset psychiatric comorbidities among individuals with ADHD, the investigators found that substance use disorders presented the strongest associations with death due to natural causes (adjusted HR = 3.23; 95% CI, 1.72-6.07), suicide (adjusted HR = 6.61; 95% CI, 4.13-10.57) and unintentional injury (adjusted HR = 10.02; 95% CI, 6.49-15.49).
“These results suggest that overall health conditions and risk of psychiatric comorbidity should be evaluated clinically to identify high-risk groups among individuals with ADHD,” Sun and colleagues wrote. “Assessment of the risk and intervention focusing on different psychiatric comorbidities might help with not only improving general quality of life for individuals with ADHD, but also preventing premature deaths due to various causes.” – by Savannah Demko
Disclosures: Sun reports personal fees from China Scholarship Council. Please see the study for all other authors’ relevant financial disclosures.