The following article is part of conference coverage from the American Academy of Neurology (AAN) 2021 Virtual Annual Meeting. Neurology Advisor’s staff will be reporting breaking news associated with research conducted by leading experts in neurology. Check back for the latest news from the AAN 2021 Virtual Annual Meeting.

 

Patients with a history of depression or anxiety were significantly younger at age of onset of Alzheimer disease (AD), according to study findings presented at the American Academy of Neurology 2021 Virtual Annual Meeting, held April 17 to 22, 2021.


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Although depression has been noted as a risk factor that may accelerate the development of AD, there is limited research available on the effects of psychiatric diseases such as mood and psychotic disorders and post-traumatic stress disorder (PTSD).

The study researchers screened 1500 patients with AD who were patients at the Memory and Aging Center of the University of California, San Francisco, for a history of the psychiatric disorders of depression, anxiety, bipolar disorder, schizophrenia, and PTSD.

They ascertained disease prevalence and association with age at onset, demographics, typical Alzheimer disease risk factors (hypertension, hyperlipidemia, diabetes mellitus, education, and apolipoprotein E4 [ApoE4] gene) and novel AD-associated factors (not being right-handed, or having a learning disability, an autoimmune disease, or a seizure history).

They found that 43.3% of the patients had a history of depression, 32.3% had a history of anxiety, 1.2% had a history of bipolar disorder, 1% had a history of PTSD, and 0.4% had a history of schizophrenia.

Patients with depression or anxiety were 2.1 and 3.0 years younger, respectively, at the age of onset of Alzheimer disease (P <.001). The differences in age of onset of AD doubled with each additional psychiatric diagnosis.

Patients with only 1 psychiatric disorder tended to be 1.5 years younger at age of onset while those with 2 psychiatric conditions were 3.3 years younger and those with 3 or more diagnoses had a 7.3-year reduction in age of onset (P <.001).

Patients with depression and anxiety were more likely to be women and had fewer typical AD risk factors. The cohort of participants with depression experienced a significantly higher number of autoimmune diseases (P =.01) while the cohort of participants with anxiety had more frequent seizures (P =.002).

The age of onset differences compounding with additional psychiatric diagnoses suggested each “possess unique and additive effects” on AD, the study researchers stated.

They concluded that the presence of depression may “reflect a greater burden of neuroinflammation and anxiety a greater degree of hyperexcitability, given associations with autoimmune disease and seizure.”

Reference

Eijansantos E, Allen I, Deleon J, et al. History of psychiatric disease inversely correlates with age of onset in Alzheimer’s disease. Presented at: the American Academy of Neurology 2021 Virtual Annual Meeting; April 17-22, 2021. Abstract S19.003