Psychological distress is associated with poorer later-life cognitive performance and increased risk for dementia, though not with cognitive decline over time, according to results of a study published in Alzheimer’s & Dementia.

In a multi-cohort study, researchers examined associations between psychological distress and subsequent cognitive outcomes and dementia risk. They pooled data from 5 longitudinal studies: the Caerphilly Prospective Study (CAPS), English Longitudinal Study of Ageing (ELSA), National Child Development Study (NCDS), National Survey of Health and Development (NSHD), and Whitehall II (WHII).

The analysis included 24,564 participants. Across cohorts, baseline sample sizes ranged from 1180 to 9022 participants. Cohorts comprised 44.7% to 100% men, with mean baseline ages ranging from 23 to 64.1 years, and 3.3% to 25.5% of participants reporting long-term health conditions. Between 7.6% and 27.7% of participants reported clinically significant psychological distress at baseline.

 

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

Greater baseline psychological distress was associated with worse subsequent fluid cognitive performance at a mean age of 62 to 72 years (adjusted b, -0.03; 95% CI, -0.06 to -0.01; I2=70%). Similar associations were observed for clinically significant distress (b, -0.1; 95% CI, -0.1 to 0.0; I2=62%), intermittent distress (b, -0.1; 95% CI, -0.2 to -0.02; I2=83%), and persistent distress (b, -0.1; 95% CI, -0.1 to -0.1; I2=0%).

In analyses of cognitive trajectories, psychological distress was not associated with overall cognitive decline in pooled models. Although cohort-specific analyses showed decline in ELSA (b, -0.04; 95% CI, -0.04 to -0.04), NSHD (b, -0.01; 95% CI, -0.01 to 0.004), and WHII (b, -0.01; 95% CI, -0.01 to 0.01), these findings were not consistent across studies.

Baseline psychological distress was also associated with increased odds of dementia at follow-up (adjusted odds ratio [aOR], 1.1; 95% CI, 1.0-1.2; I2=0%). Increased dementia risk was observed for clinically significant distress (aOR, 1.3; 95% CI, 1.1-1.5; I2=0%), intermittent distress (odds ratio [OR], 1.3; 95% CI, 1.0-1.7; I2=40%), and persistent distress (OR, 1.4; 95% CI, 1.0-2.0; I2=44%).

Age-stratified analyses showed that psychological distress was associated with dementia when assessed at ages 55 to 64 years (OR, 1.3; 95% CI, 1.2-1.4; I2=0%) and 65 to 75 years (OR, 1.3; 95% CI, 1.2-1.4; I2=14%), but not at ages 45 to 54 years (OR, 1.1; 95% CI, 0.9-1.3; I2=34%).Study limitations included heterogeneity across cohorts in population characteristics, measurement of psychological distress, and outcome assessment.

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