Researching Effective Sleep Treatments (REST): The effectiveness of partner-assisted treatments for insomnia using Cognitive Behavioural Therapy (CBT) and sleep hygiene therapy (SHT).

INTERVENTION: Participants will be randomised to one of three interventions: partner‐assisted Cognitive Behaviour Therapy for Insomnia (PA‐CBTI), individual Cognitive Behaviour Therapy for Insomnia (I‐CBTI) or partner‐assisted sleep hygiene therapy (PA‐SHT). Regardless of which intervention they are assigned, participants will attend 7 weekly 1‐hour treatment sessions, wear an actigraph and complete daily sleep diaries. CBTi is a multicomponent intervention. Clinicians work with clients to help them make changes to their sleep‐wake patterns, to improve sleep. This includes setting regular sleep and wake times, getting out of bed when one is unable to sleep, sleep restriction and stimulus control. CBTi also addresses common misconceptions about sleep and unhelpful thought patterns, which may be perpetuating sleep problems. Finally, CBTi includes education about improving the sleep environment and relaxation techniques. SHT focuses on education about sleep‐wake cycles and helps participants to change and improve basic lifestyle habits that impact on sleep (e.g., avoiding caffeine late in the day). In the partner‐assisted conditions, the partner participates in every therapy session, and learns all the same information as the patient. The partner plays a supportive role, helping the patient to make behavioural changes in between treatment sessions. This includes reinforcing positive changes and helping to create an environment that encourages positive change. All treatment sessions, regardless of condition, take the format of individual one‐on‐one sessions (i.e., one sleep clinician per couple or client). Sleep clinicians are registered psychologists, with expertise in sleep. Irrespective of condition, participants are asked to complete a daily sleep diary throughout the treatment program and to practice 1‐3 strategies learnt in session in between therapy sessions. Ideally, these strategies are used daily. Participants will complete a daily sleep diary and a weekly adherence questionnaire with the help of the sleep clinician to monitor adherence. Participants will wear the actigraph 24‐hours per day (except when engaged in activities that may damage the device) throughout the 7 week intervention period. CONDITION: Insomnia Disorder PRIMARY OUTCOME: A primary outcome is adherence to Sleep Restriction as assessed by the sleep diary. A primary outcome is adherence to Stimulus Control as assessed by the sleep diary. A primary outcome is completion rates as assessed by those randomised to a treatment condition and who completed at least the first treatment session INCLUSION CRITERIA: Key inclusion criteria for individuals with Insomnia Disorder include: a) diagnosis of Insomnia Disorder, per DSM‐5; b) 18 years old or over; c) English literacy; and d) having a bed partner willing to participate in the study. Bed partners may or may not have problems sleeping. SECONDARY OUTCOME: Another secondary outcome is bed partners' sleep‐wake patterns and problems. This is operationalised by activity recorded via sleep diaries. Another secondary outcome is psychiatric symptoms ‐ post‐traumatic stress disorder. This is operationalised by scores on the the Posttraumatic Stress Disorder Checklist‐5. Client sleep‐diary sleep efficiency Psychiatric symptoms ‐ anxiety. This is operationalised by scores on the Beck Anxiety Inventory. Psychiatric symptoms ‐ depression. This is operationalised by scores on the Patient Health Questionnaire‐9. Quality of Life. This is operationalized by the Quality of Life Enjoyment and Satisfaction Questionnaire Short Form. The bed partner's insomnia symptoms as assessed with the Insomnia Severity Index. The bed partners' sleep‐wake patterns and problems as assessed with actigraphy. The secondary outcome is relationship functioning. This is operationalised by scores on the Dyadic Adjustment Scale, Communication Patterns Questionnaire and Partner Criticism Scale.