Temporal Relationship Between Depressive Symptoms and Cognition in Mid and Late Life: A Longitudinal Cohort Study

Objectives: To examine the bidirectional temporal relationship between depressive symptoms and cognition in relation to risk, reaction, and prodrome. Design: Cross-lag analysis of longitudinal data collected online at baseline and 12-month follow-up. Setting and Participants: A United Kingdom population cohort of 11,855 participants aged 50 years and over. Measures: Patient Health Questionnaire-9 (depressive symptoms), cognitive measures: Paired Associate Learning, Verbal Reasoning, Spatial Working Memory, and Digit Span. Results: Depressive symptoms predicted a decline in paired associates learning [beta = -.020, P = .013, (95% confidence interval [CI], -.036, -.004)] and verbal reasoning [beta = -.014, P = .016, (95% CI -.025, -.003)] but not vice versa. Depressive symptoms predicted [beta = -.043, P < .001, (95% CI -.060, -.026); beta = -.029, P < .001, (95% CI -.043, -.015)] and were predicted by [beta = -.030, P = < .001, (95% CI -.047, -.014); d = -.025, beta = .003, (95% CI -.041, -.009)1, a decline in spatial working memory and verbal digit span, respectively. Conclusions and Implications: Depressive symptoms may be either a risk factor or prodrome for cognitive decline. In addition, a decline in attention predicts depressive symptoms. Clinical implications and implications for further research are discussed. (C) 2020 AMDA - The Society for Post-Acute and Long-Term Care Medicine.