The purpose of this study is to investigate the mechanisms of change in Cognitive Behavioral Therapy for insomnia (CBTi) in a sample of adults aged 50-65. This study aims to evaluate the pre-post treatment change in sleep, circadian rhythms, biomarkers, cognitive performance, and structural and functional magnetic resonance imaging scans (MRI).

Baseline Part 1:

• Online demographic and contact information
• Schedule Baseline Part 2 with the investigators via online link
• 1 week of daily sleep diaries

Baseline Part 2:

• Internet-based interview with the investigators to confirm study eligibility requirements
• Online self-report questionnaires
• 2 weeks of daily sleep diaries
• 2 weeks of sleep/wake assessment wearing a watch-like activity monitor (Actiwatch)

Objective Baseline:

• Single-night, diagnostic in-home sleep study, including and the following equipment:

  • Adhesive patch which will adhere to the arm
  • Sensor belts worn around the chest, fitted with nasal canula, pulse oximeter, and 3 electrodes which will adhere to the back of the neck and behind each ear

• Next-day appointment:

  • Neuropsychological assessment
  • Structural and functional magnetic resonance imaging scan (MRI)
  • Non-invasive blood pressure readings
  • Low-volume Blood draw (used to obtain genetic biomarkers)
  • Removal of adhesive patch

• Next-day evening (2-nights):

  • Consumable capsule
  • Sensor belt worn around the chest/abdomen Random Assignment: If it is determined the participant is eligible for the study, participants will be randomly assigned to one of the treatment groups (in-person, telehealth or internet delivered) or asked to wait to start treatment.

Treatment Phase I:

• Participants will complete up to 12 weeks of insomnia treatment or wait for treatment ("waitlist") 12-Week Post-treatment Part 1:
• Complete 2 weeks of an online daily sleep diary and actigraphy
• Complete online self-report questionnaires

Objective 12-Week Post-treatment:

• Repeat "Objective Baseline" outlined above

Treatment Phase II (WLC):

• Treatment will start for participants who had been assigned to the waitlist condition 3-Month Follow-Up:
• Complete online self-report questionnaires

Inclusion Criteria:

• Aged 50-65
• Normal hearing with or without hearing aids
• Ability to speak and read English and ability to give informed consent
• Possession of a computer with video and audio capabilities
• Meets DSM-5 Criteria for Insomnia Disorder
• Internet speed sufficient for participating in teletherapy (e.g., Zoom Health) or SHUTi (for iCBTi group)
• MoCA scores ≥24 will be deemed normal cognitive status and considered eligible for study participation and/or assessed by the ability to comprehend the baseline screening questionnaires
• Willing to refrain from new external behavioral health or medication treatment for issues pertaining to sleep during participation in the study
• Indication that the individual plans to be in the area for the 6 months following the first baseline assessment

Exclusion Criteria:

• Failure to meet the above "inclusion criteria"
• Current circadian rhythm disorder, sleep deprivation, or hypersomnia and related sleep disorders (assessed with clinical interview and/or self-report) as CBTi has not been validated in these populations. Verified by self-report and/or clinical interview (SCISD-R)
• Untreated sleep disordered breathing (e.g., obstructive sleep apnea) assessed by self-report, clinical interview, and/or diagnostic sleep study (i.e., baseline sleep study PSG)
• Failing to meet criteria for MRI scan (e.g., having metallic implants); see Pre-screen MRI Checklist for full list of exclusions for MRI scans.
• Fear/phobia of needles (conflict with blood draw) and/or small spaces (conflict with MRI scanner)
• Current suicide risk meriting crisis intervention as assessed by the Patient Health Questionnaire (PHQ-9) and/or disclosure of serious suicidal ideation
• Pregnancy (self-report, proposed instruments and treatments have not been validated in this population)
• Sleep efficiency > 85%, assessed by the sleep diary
• Serious mental health diagnosis (e.g., bipolar disorder or psychosis) assessed by structured interview (M.I.N.I.)
• Currently engaged in evidence-based psychotherapy for Insomnia (i.e., Cognitive Behavioral Therapy) by self-report
• Failure to follow protocol (e.g., consistent "no show" for appointments, answering questionnaires dishonestly, refusal to complete more than 2 assessments [e.g., fMRI and Neuropsych])

The participant and outcomes assessor will not be aware of participant study conditions.