Longitudinal associations of psychological distress with subsequent cognitive decline and dementia: a multi-cohort...

Psychological distress has been linked with cognitive impairment. However, whether the relationship is causal, reflects preclinical dementia neuropathology, or confounding by common causes remains unclear.

In five UK longitudinal studies, we examined associations of psychological distress with subsequent cognition using linear and mixed effects models, and dementia using logistic regression. We examined variation by age-at-assessment, severity, and distress persistence, combining study-specific estimates using two-stage individual participant data meta-analysis.

Pooling across studies (N = 24,564), greater baseline psychological distress was associated with lower subsequent cognitive level (β = -0.03 [95% confidence interval [CI]: -0.06; -0.01]; I² = 70%), and dementia (odd ratio [OR] = 1.1 [1.0; 1.2]; I² = 0%), but not cognitive change. Associations were found for clinically significant, persistent and intermittent distress. Dementia was associated with distress assessed at ages 65-75, and 55-64, but not 45-54 years.

Findings highlight the relevance of psychological distress in later cognitive outcomes, with potential future implications for dementia prevention and identifying high-risk groups.