Purpose of Review: Recent research supports that Cognitive Behavioral Therapy for Insomnia (CBT-I) improves both insomnia and depression symptoms. The primary purpose of the current review was to summarize potential mechanistic pathways linking insomnia and depression while evaluating how improvements in sleep via CBT-I may lead to reduced depressive symptoms. Recent Findings: The current literature supports that there are several potential biological, behavioral, and cognitive-affective mechanisms, including improved hypothalamic-pituitary-adrenal (HPA) axis and inflammatory functioning, behavioral activation, and emotion regulation, that may explain the antidepressant effects of CBT-I. Summary: Critically evaluating the potential mechanisms by which CBT-I improves depression (e.g., HPA-axis, inflammatory, behavioral, and emotional processes) will inform future efforts to enhance the overall effectiveness of CBT-I in patients with comorbid depression. Specifically, it will identify specific mechanisms that can be the focus of more targeted interventions or strategies to streamline CBT-I in patients with depression.
Vargas et al. (Thu,) studied this question.