Efficacy of CBT-I and Lemborexant Medication for Different Subtypes of Chronic Insomnia

Inclusion Criteria: * 18 years of age or older at the time of enrolment * Meeting Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria for insomnia disorder (Duke Sleep Interview), with total Insomnia Severity Index (ISI) score \> 10, and score ≥ 2 on either the interference or distress item * Minimal symptoms of anxiety and/or depression with Patient Health Questionnaire (PHQ-9) \> 4 and/or Generalized Anxiety Disorder (GAD-7) \> 4 * Ability to read and understand French or English * Ability to use a smartphone, tablet, or computer, and access to home internet connection Exclusion Criteria: * Presence of a lifetime diagnosis of any psychotic or bipolar disorder * Untreated psychiatric disorder (e.g., major depression) or risk for suicide * Substance/alcohol use disorder within the past year * Any life-threatening or progressive medical illness (e.g., cancer, chronic obstructive pulmonary disease) or neurological degenerative disease (e.g., dementia) * Current use of sleep-promoting medications (prescribed or over-the-counter) or cannabis-derived products for sleep more than two nights per week * Current use of tricyclic antidepressants, monoamine oxidase inhibitors, or atypical antidepressants * Reported diagnosis of sleep disorder other than insomnia (e.g., obstructive sleep apnea, restless legs syndrome, rapid eye movement behavior disorder, delayed phase sleep disorder, narcolepsy) * Total score \> 5 on the Stop-Bang Questionnaire and/or clinical symptoms suggestive of sleep apnea (excessive daytime sleepiness), or Epworth score \> 10, restless legs syndrome or other signs of other sleep disorders * Atypical sleep schedules (i.e., habitual bedtimes later than 2:00 AM and rising times later than 10:00 AM on more than two days/nights per week as documented from a sleep diary) * Working night shifts more than five nights per month in the last six months * Consuming 2 or more alcoholic beverages per day regularly (3 days or more per week) * Any contra-indications to using the study medication, including lung disease/breathing problems (e.g., chronic obstructive pulmonary disease), use of strong or moderate CYP3A inducers (strong - rifampin, carbamazepine, and St. John's Wort) (moderate - bosentan, efavirenz, etravirine, and modafinil), pregnant and breastfeeding women * Not using any method of birth control