Cognitive, behavioral and circadian rhythm interventions for insomnia alter emotional brain responses

BACKGROUND: 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. We here investigate how different sleep interventions alter emotion-related brain activity in people with insomnia at high risk of developing depression.

METHODS: Functional magnetic resonance imaging (fMRI) was used to assess how the amygdala response to emotional stimuli (negative facial expression) in 122 people with insomnia disorder differed from 36 controls, and changed after six weeks of either no treatment (NT) 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 one year.

RESULTS: Only combined treatment (CBT-I+CRS) significantly increased the amygdala response, compared to NT, 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=0.021). 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=0.042).

DISCUSSION: This largest fMRI study on insomnia treatment to date, shows that a combined cognitive, behavioral, and circadian intervention enhances emotional brain responsiveness, and might improve resilience in insomnia patients at high risk of developing depression.