TOPLINE:

Depression, anxiety, and posttraumatic stress disorder (PTSD) were associated with increased risk for earlier onset of Alzheimer’s disease (AD) compared with not having the conditions, new research showed. Additionally, an increase in the number of comorbid psychiatric conditions was associated with decreases in the age at AD onset. 

METHODOLOGY:

• Researchers analyzed data from a cohort of patients with AD from the University of California, San Francisco Memory and Aging Center (UCSF MAC; n = 1500; half with early-onset AD) to determine the prevalence of psychiatric conditions.
• They compared the findings with data for more than 8000 participants with AD from the National Alzheimer’s Coordinating Center (NACC).
• Psychiatric conditions, including depression, anxiety, PTSD, bipolar disorder, and schizophrenia, were retrospectively identified using patient charts and first visit notes.

TAKEAWAY:

• Within the UCSF MAC cohort, 43% of patients had a history of depression, 32% had anxiety, 1% had bipolar disorder, 1% had PTSD, and 0.4% had schizophrenia.
• Participants with early-onset AD had significantly higher rates of depression (P < .001) and anxiety (P < .001) than those with late-onset AD.
• Patients with depression, anxiety, or PTSD were 2.2, 3.0, and 6.8 years younger at AD symptom onset, respectively, compared with those without these conditions (P < .001 for depression and anxiety; P < .05 for PTSD). NACC cohort individuals with current symptoms of depression or anxiety were 2.1 years younger at AD onset compared with those without the symptoms (P < .001).
• In the UCSF MAC cohort, having one psychiatric condition was linked to a 1.5-year reduction in age at AD onset, two conditions to a 3.3-year reduction, and three or more conditions to a 7.7-year reduction compared with having no conditions (P < .001 for all comparisons). Similarly, NACC participants with one disorder developed AD 1.5 years earlier (P < .001) and those with two developed AD 3.2 years earlier (P < .001).

IN PRACTICE:

“These findings suggest that psychiatric conditions contribute distinctively to AD susceptibility, underscoring the importance of obtaining detailed psychiatric symptom assessments in individuals with neurodegenerative disease,” the investigators wrote.

SOURCE:

This study was led by Emily Eijansantos, University of California, San Francisco. It was published online on October 23 in Alzheimer’s & Dementia.

LIMITATIONS:

This study was limited by its retrospective chart review design, which was prone to ascertainment bias. Generational differences in the recognition and screening of psychiatric conditions may have influenced the findings. The low rates of bipolar disorder and schizophrenia may have reflected underrepresentation or systemic dropout due to shorter lifespans and increased healthcare barriers in these groups. Additionally, because diagnoses were clinically based, amyloid pathology was not confirmed in all participants.

DISCLOSURES:

This study was supported by multiple organizations, including the National Institute on Aging, the National Institute on Deafness and Other Communication Disorders, the National Institute of Neurological Disorders and Stroke, the Hellman Research Scientist Award, and the Arking Foundation for Frontotemporal Dementia. Several investigators reported having financial or other ties with various pharmaceutical companies, journals, or institutions, which are fully listed in the original article. The other 16 investigators reported having no relevant financial relationships.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.