Impact of Insomnia Treatment on Brain Responses During Resting-state and Cognitive Tasks

Individuals with chronic insomnia have persistent difficulty falling and staying asleep, as well as complaints of altered daytime functioning that may be associated with cognitive impairments. The neural processes underlying these daytime complaints may involve abnormal activation of brain regions and neural networks involved in working memory, memory encoding and emotions. The goal of this study is to assess whether a psychological treatment for insomnia will reverse these abnormalities in brain responses to cognitive tasks and at rest. A secondary objective of the study is to characterize impairments in attentional processing and assess if the impairments can be reversed by the psychological treatment. We hypothesized that the psychological treatment for insomnia will lead to a normalization of the brain responses to working memory, declarative memory encoding, insomnia-related stimuli, and the functional connectivity within the default-mode and limbic networks.

Inclusion Criteria: 80 participants with chronic primary insomnia (40 per group) 40 good sleepers Exclusion Criteria: 1. Older than 65 y.o. or younger than 25 y.o. 2. Contraindication to the MRI scanning 3. Current neurological disorder 4. Past history of brain lesion 5. Major surgery (i.e., requiring general anesthesia) in the past 3 months 6. Untreated thyroid disorder 7. Chronic pain syndrome self-reported as interfering with sleep 8. Recent and severe infection in the past 3 months 9. Active cancer, or remitted cancer with cancer treatment within the last 2 years 10. Stroke 11. Myocardial infarct 12. Arterial bypass or angioplasty 13. Pacemaker 14. Heart failure causing limitation of ordinary physical activity 15. Renal insufficiency 16. Sleep apnea with an apnea-hypopnea index \> 5/h 17. Restless legs syndrome with symptoms 3 days or more per week 18. Periodic limb movements during sleep with index \> 15/h 19. REM-sleep behavior disorder 20. Narcolepsy and other central disorders of hypersomnolence 21. Sleepwalking more than once/month 22. Having worked on night shifts or rotating shifts for more than 2 weeks in the last 3 months or expecting to do so during the study period 23. Severe mental disorders: bipolar disorder (Type I), schizophrenia, anxiety disorders, major depressive disorder, current substance use disorder, current post-traumatic stress disorder 24. Current suicidality 25. Frequent alcohol consumption (\>10 glasses/week) or use of cannabis (more than once a week) or illicit drugs (more than once a month) 26. Smoking cigarettes more than 10 cigarettes/day 27. Pregnant or breastfeeding women 28. Current psychotherapy or past cognitive-behavioural therapy for insomnia 29. Current use of medication for depression or anxiety 30. Unable to stop hypnosedative medications for at least 2 weeks prior to the first assessment 31. For good sleepers: insomnia symptoms more than 3 times/ week.