Dementia Odds Significantly Increase With More Psychiatric Comorbidities

Highest posterior probabilities seen with mood and anxiety disorder co-occurrence

By Lori Solomon HealthDay Reporter

WEDNESDAY, Sept. 10, 2025 (HealthDay News) — Dementia odds significantly increase with the number of psychiatric comorbidities, according to a study published online Sept. 9 in BMJ Mental Health.

Edouard Baudouin, M.D., from Hôpital Paul Brousse in France, and colleagues assessed the odds of dementia (all types) among individuals with several psychiatric disorders and identified relevant co-occurrence patterns. The analysis included clinical data (Aug. 29, 2009, to Oct. 29, 2023) for 3,688 patients aged 45 years and older with at least one psychiatric disorder: depressive disorders, anxiety disorders, psychotic disorders, substance use disorders, personality disorders, or bipolar disorders.

The researchers found that compared with those with one psychiatric disorder (70.7 percent of patients), the odds of dementia were higher for those with two comorbidities (21.4 percent of patients; adjusted odds ratio, 2.3) and even higher for those with four comorbidities (1.8 percent; adjusted odds ratio, 11.1). For patients with co-occurrence of mood and anxiety disorders, the mean posterior probability of dementia ranged from 48 to 89.6 percent.

“These findings highlight the need for targeted dementia screening and preventive actions in patients developing more than one psychiatric disorder, particularly those with both anxiety and mood disorders,” the authors write.