Research master thesis | Psychology (research) (MSc)
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Objective: This study aimed to clarify the relationship between the course of core depressive symptoms and the course of insomnia symptoms in older adults with a depressive disorder, and to...Show moreObjective: This study aimed to clarify the relationship between the course of core depressive symptoms and the course of insomnia symptoms in older adults with a depressive disorder, and to identify predictors of an unfavorable versus a favorable course of core depressive symptoms and insomnia symptoms. Method: We examined 329 older adults (median age 69 (IQR 65-75), 66.9% women) with a depressive disorder within the Netherlands Study of Depression in Older persons (NESDO), a naturalistic cohort study with a six-year follow-up and assessments every six months in between. Core depressive symptoms and insomnia symptoms were assessed with 14 and 3 items, respectively, from the Inventory of Depressive Symptomatology (IDS). We applied growth mixture modelling to identify classes of participants with similar trajectories of core depressive symptoms and insomnia symptoms. The association between core depressive and insomnia symptom trajectories was examined with a chi-squared test. Finally, we investigated predictors of class membership for core depressive symptoms and for insomnia symptoms using multinomial logistic regression. Results: We identified three trajectories of core depressive symptoms: high and stable (22.2% of participants were assigned to this class), moderate and declining (37.4%), and low and declining (40.4%). We identified four trajectories of insomnia symptoms: high and stable (23.1%), moderate and stable (55.6%), low and increasing (7.6%), and moderate and declining (13.7%). There was a significant association between core depressive and insomnia symptom trajectories, in particular for the most and least favorable trajectories. Number of chronic diseases, a comorbid anxiety disorder, and functional limitations predicted less favorable core depressive symptom trajectories. We found no predictors for insomnia symptom trajectories. Conclusion: Persistent insomnia symptoms are highly prevalent in older adults with depression, even in those with improving core depressive symptoms. This highlights the need for separate treatment of insomnia symptoms in addition to depression interventions.Show less