Burden of psychiatric disease inversely correlates with Alzheimer's age at onset

Depression is regarded as a risk factor for Alzheimer's disease (AD). Associations between AD and other psychiatric disorders are less clear.

We screened 1,500 AD UCSF Memory and Aging Center patients for prevalence of psychiatric disorders and compared results to 8,267 NACC AD participants.

AD with depression, anxiety, or post-traumatic stress disorder were significantly younger at age at onset than AD without (p < 0.001; p < 0.001; p < 0.05). Comorbidity of depression, anxiety and PTSD led to further decreases in AD age at onset. Within the NACC cohort, we further demonstrated an inverse relationship between the severity of depression and anxiety symptoms and AD age at onset.

Depression, anxiety, and post-traumatic stress disorder are inversely associated with AD age at onset. Age at onset further decreases with increasing number of psychiatric conditions and increasing severity of symptoms, suggesting that overall burden of psychiatric disease is highly relevant to AD.

Retrospective chart review revealed that in patients with AD, those who also had depression, anxiety, or post-traumatic stress disorder were significantly younger at age at onset than those without. Increasing burden of psychiatric disease, both in severity of psychiatric symptoms and number of comorbid psychiatric conditions, produced serial decreases in the age at onset of AD. In patients with AD, those with depression were more likely to have autoimmune disease, and those with anxiety were more likely to have a history of seizures.