Types of Insomnia Mediate the Bidirectional Relation Between Anxiety and Depressive Symptoms Longitudinally in Older Adults

The current study examined onset and maintenance insomnia as mediators of the bidirectional relation between anxiety and depressive symptoms over a three-year period. The sample included 3,415 US community-dwelling Medicare beneficiaries aged 66-103. Participants completed measures of types of insomnia, anxiety symptoms, and depressive symptoms at four time points. Analyses included two double mediation models adjusted for baseline depressive or anxiety symptoms, chronic health problem burden, use of sleep medications, age, and sex. Both covariate-adjusted models showed significant direct relations between anxiety and depressive symptoms, and these relations were modestly partially mediated by onset and maintenance insomnia. In older adults, onset and maintenance insomnia are distinct outcomes of both anxiety and depressive symptoms and also predictors of each symptom cluster. Further research testing these models is warranted and, if supported, may support prevention and treatment studies focused on primary and secondary prevention of these problems in older adults.