Eating disorders are highly associated with mortality, and anorexia nervosa is the second most lethal psychiatric disorder, surpassed only by substance use disorder (SUD). Patients with eating disorders frequently have comorbid SUDs. In a recent retrospective cohort study using the Danish nationwide registers, 20,759 patients with eating disorders were included, with 80,036 matched control participants. Hazard ratios were calculated to compare all-cause mortality risk between patients with eating disorders and control participants with and without a lifetime SUD diagnosis (abuse or dependence on illicit substances, cannabis, alcohol). A higher risk of all-cause mortality was observed in patients with each type of eating disorder compared to control participants without SUDs. Among those who abused alcohol and/or cannabis, the all-cause mortality hazard ratio was 11.28 [95% CI=7.01, 18.16], 5.86 [95% CI=3.37, 10.1], and 10.86 [95% CI=6.74, 17.50]), or illicit drugs alone or in combination with alcohol and/or cannabis (adjusted hazard ratios, respectively, were 22.34 [95% CI=15.13, 33.00], 11.43 [95% CI=7.14, 18.28], and 15.53 [95% CI=10.15, 23.78]), than in those without SUDs (adjusted hazard ratios, respectively, were 3.21 [95% CI=2.43, 4.23], 1.24 [95% CI=0.88, 1.77], and 4.75 [95% CI=3.57, 6.31]). Control participants with SUDs also demonstrated an elevated risk of all-cause mortality relative to control participants without SUDs, however not as much as patients with an eating disorder and comorbid SUD. The results suggest that SUDs contribute to an additive effect on excess mortality in patients with eating disorders, thus efforts on interventions for SUDs should be made for this vulnerable population.

Reference:

Mellentin A. et al. The American Journal of Psychiatry 2022; 179(1):46-57. Abstract