This study examines the bidirectional association between depressive symptoms and cognitive function in a nationally representative sample of English adults aged 50 years or older over a 16-year follow-up period. The analysis included 8,268 participants, with data collected every two years from 2002 to 2003 and 2018 to 2019. Cognitive function was assessed using memory and verbal fluency tests, while depressive symptoms were measured using the Center for Epidemiologic Studies Depression Scale. Key findings include: - Higher depressive symptoms at baseline were associated with poorer memory and verbal fluency. - A steeper linear change in depressive symptoms was linked to accelerated memory decline. - Memory decline was associated with an acceleration in depressive symptoms over time. - The bidirectional association was not observed for verbal fluency. The study suggests that changes in depressive symptoms are intrinsically linked to cognitive performance, highlighting the need for integrated assessment and treatment approaches in clinical practice. Early intervention in depressive symptoms could potentially slow down or delay memory decline in later life.This study examines the bidirectional association between depressive symptoms and cognitive function in a nationally representative sample of English adults aged 50 years or older over a 16-year follow-up period. The analysis included 8,268 participants, with data collected every two years from 2002 to 2003 and 2018 to 2019. Cognitive function was assessed using memory and verbal fluency tests, while depressive symptoms were measured using the Center for Epidemiologic Studies Depression Scale. Key findings include: - Higher depressive symptoms at baseline were associated with poorer memory and verbal fluency. - A steeper linear change in depressive symptoms was linked to accelerated memory decline. - Memory decline was associated with an acceleration in depressive symptoms over time. - The bidirectional association was not observed for verbal fluency. The study suggests that changes in depressive symptoms are intrinsically linked to cognitive performance, highlighting the need for integrated assessment and treatment approaches in clinical practice. Early intervention in depressive symptoms could potentially slow down or delay memory decline in later life.