Six-year trajectories of core depressive symptoms and insomnia symptoms in depressed older adults: a NESDO study

This study aimed to identify trajectories of core depressive symptoms and insomnia symptoms in depressed older adults, their prevalence and association, and predictors of unfavorable trajectories.

We examined 6-year follow-up data of 329 depressed older adults from the Netherlands Study of Depression in Older persons. Core depressive symptoms and insomnia symptoms were assessed with the Inventory of Depressive Symptomatology. We applied growth mixture modeling to identify classes of participants with similar trajectories of core depressive symptoms and insomnia symptoms. The association between core depressive and insomnia symptom trajectories and predictors of these trajectories were examined.

We identified three core depressive symptom trajectories: low and declining (40.4%), moderate and declining (37.4%), and high and stable (22.2%); and four insomnia symptom trajectories: moderate and declining (13.7%), low and increasing (7.6%), moderate and stable (55.6%), and high and stable (23.1%). Participants with favorable core depressive symptom trajectories often had unfavorable insomnia symptom trajectories. Older age, chronic diseases, and functional limitations predicted unfavorable core depressive symptom trajectories. Functional limitations predicted unfavorable insomnia symptom trajectories.

Trajectories of core depressive and insomnia symptoms in depressed older adults were partly associated, but insomnia symptoms often persisted despite improving core depressive symptoms, highlighting the importance of different targeted interventions.