Depression is a major global health concern, yet evidence on depressive symptom severity among older adults with neurodegenerative disorders in Africa remains limited. This study assessed depressive symptom severity and associated sociodemographic, clinical and psychosocial factors in Nigeria.

This hospital–based cross-sectional study recruited 304 adults aged ≥60 years with clinically confirmed Alzheimer’s disease, Parkinson’s disease or Lewy body dementia from six federally accredited neuropsychiatric hospitals (November 2024–October 2025). Depressive symptoms were assessed using the GDS-15. Descriptive statistics, chi-square tests and multivariable logistic regression were used.

Severe depressive symptoms were observed in 85.2% of participants. Factors associated with severe symptoms included age ≥70 years (AOR = 4.32, 95% CI: 2.20–8.49), male sex (2.80, 1.49–5.27), unmarried/separated status (2.50, 1.22–5.13), living with family (6.27, 3.19–12.31), medication dependence (11.8, 5.88–23.79) and comorbidities (16.3, 7.70–34.57). Tertiary education was inversely associated with severe symptoms (AOR = 0.41, 95% CI: 0.21–0.80).

Severe depressive symptoms were highly prevalent in this clinically selected sample. Integrated depression screening, appropriate clinical management and tailored psychosocial support are warranted.