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

Abstract

ObjectivesTo examine the bidirectional temporal relationship between depressive symptoms and cognition in relation to risk, reaction, and prodrome. DesignCross-lag analysis of longitudinal data collected online at baseline and 12-month follow-up. Setting and ParticipantsA United Kingdom population cohort of 11,855 participants aged 50 years and over. MeasuresPatient Health Questionnaire-9 (depressive symptoms), cognitive measures: Paired Associate Learning, Verbal Reasoning, Spatial Working Memory, and Digit Span. ResultsDepressive symptoms predicted a decline in paired associates learning [β = −.020, P = .013, (95% confidence interval [CI], ‒.036, −.004)] and verbal reasoning [β = −.014, P = .016, (95% CI ‒.025, −.003)] but not vice versa. Depressive symptoms predicted [β = −.043, P < .001, (95% CI ‒.060, −.026); β = −.029, P < .001, (95% CI ‒.043, −.015)] and were predicted by [β = −.030, P = < .001, (95% CI ‒.047, −.014); β = −.025, P = .003, (95% CI ‒.041, −.009)], a decline in spatial working memory and verbal digit span, respectively. Conclusions and ImplicationsDepressive 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.