Cognitive, Behavioral, and Circadian Rhythm Interventions for Insomnia Alter Emotional Brain Responses

The highest risk of depression is conveyed by insomnia. This risk can be mitigated by sleep interventions. Understanding brain mechanisms underlying increased emotional stability following insomnia treatment could provide insight relevant to the prevention of depression. Here, we investigated how different sleep interventions alter emotion-related brain activity in people with insomnia at high risk of developing depression. Functional magnetic resonance imaging was used to assess how the amygdala response to emotional stimuli (negative facial expression) in 122 people with insomnia disorder differed from 36 control subjects and how the amygdala response changed after 6 weeks of either no treatment or internet-based circadian rhythm support (CRS), cognitive behavioral therapy for insomnia (CBT-I), or their combination (CBT-I+CRS). Effects on depression, insomnia and anxiety severity were followed up for 1 year. Only combined treatment (CBT-I+CRS) significantly increased the amygdala response, compared with no treatment, CBT-I, and CRS. Individual differences in the degree of response enhancement were associated with improvement of insomnia symptoms directly after treatment (r = −0.41, p = .021). Moreover, exclusively CBT-I+CRS enhanced responsiveness of the left insula, which occurred in proportion to the reduction in depressive symptom severity (r = −0.37, p = .042). This functional magnetic resonance imaging study on insomnia treatment, the largest to date, shows that a combined cognitive, behavioral, and circadian intervention enhances emotional brain responsiveness and might improve resilience in patients with insomnia who are at high risk of developing depression.