Major depression and bipolar disorder were associated with impaired visuospatial memory performance in adults from the general population, according to study results published in the British Journal of Psychiatry.
Researchers conducted a cross-sectional study in a large group of patients with major depression (n=50,975) and bipolar disorder (n=2709), using data from the UK Biobank cohort. For comparison, they included 105,284 and 102,931 participants for the depression and bipolar cohorts, respectively. The primary objective of the study was to measure the total effects of these mood disorders on cognitive function in adults between the ages of 40 and 69 years. In addition, they aimed to quantify the effects mediated by psychotropic drug use and cardiometabolic disease.
After analysis, the researchers found small group differences on a visuospatial memory test for major depression (z-score difference, −0.07; 95% CI, −0.10 to −0.03) and bipolar disorder (z-score difference range, −0.23 to −0.17; 95% CI, −0.39 to −0.03).
In addition, they found that approximately one-quarter of the total effect was mediated by psychotropic drug use in the bipolar cohort (z-score difference, −0.05; 95% CI, −0.09 to −0.01).
One key limitation of the study was the lack of reliability in certain cognitive measures.
“Our understanding of causal pathways towards cognitive impairment in psychiatric and neurological conditions will improve as the UK Biobank cohort is followed up over time,” they concluded.
Cullen B, Smith DJ, Deary IJ, et al. Understanding cognitive impairment in mood disorders: mediation analyses in the UK Biobank cohort [published online August 15, 2019]. Br J Psychiatry. doi:10.1192/bjp.2019.188