Depression, cognition, apolipoprotein e genotype: latent class approach to identifying subtype

Area of Science:

• Gerontology
• Neuroscience
• Psychiatry

Background:

• The epsilon4 allele of apolipoprotein E (APOE-epsilon4) is linked to cognitive impairment in older adults.
• The relationship between depression subtypes, cognitive function, and APOE-epsilon4 genotype in nondemented older adults requires further investigation.

Purpose of the Study:

• To investigate the existence of a depression subtype associated with cognitive impairment in older adults.
• To examine the association between this potential depression subtype and the APOE-epsilon4 genotype.

Main Methods:

• A survey of 305 adults aged 65+ was conducted between 2001-2003, including APOE genotyping.
• Latent class modeling was used to classify participants based on Diagnostic and Statistical Manual of Mental Disorders criteria and cognitive function measures.
• The relationship between identified classes and APOE genotype was analyzed.

Main Results:

• Three distinct classes emerged: nondepressed, depressed with average cognition, and depressed with impaired cognition (including suicidal ideation).
• APOE-epsilon4 allele presence did not predict membership in any of the identified depression classes.

Conclusions:

• A distinct subgroup of older adults with depressive symptoms, cognitive impairment, and suicidal ideation may exist independently of APOE-epsilon4 status.
• Identifying these specific depression subtypes in older patients is critical due to their association with cognitive decline and suicidal risk.