Mechanisms of Change in Cognitive Behavioral Therapy for Insomnia (CBTi)

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) orSHUTi (for iCBTi group)

• MoCA scores ≥24 will be deemed normal cognitive status and considered eligible forstudy participation and/or assessed by the ability to comprehend the baselinescreening questionnaires

• Willing to refrain from new external behavioral health or medication treatment forissues pertaining to sleep during participation in the study

• Indication that the individual plans to be in the area for the 6 months followingthe first baseline assessment

Exclusion Criteria:

• Failure to meet the above "inclusion criteria"

• Current circadian rhythm disorder, sleep deprivation, or hypersomnia and relatedsleep disorders (assessed with clinical interview and/or self-report) as CBTi hasnot been validated in these populations. Verified by self-report and/or clinicalinterview (SCISD-R)

• Untreated sleep disordered breathing (e.g., obstructive sleep apnea) assessed byself-report, clinical interview, and/or diagnostic sleep study (i.e., baseline sleepstudy PSG)

• Failing to meet criteria for MRI scan (e.g., having metallic implants); seePre-screen MRI Checklist for full list of exclusions for MRI scans.

• Fear/phobia of needles (conflict with blood draw) and/or small spaces (conflict withMRI scanner)

• Current suicide risk meriting crisis intervention as assessed by the Patient HealthQuestionnaire (PHQ-9) and/or disclosure of serious suicidal ideation

• Pregnancy (self-report, proposed instruments and treatments have not been validatedin this population)

• Sleep efficiency > 85%, assessed by the sleep diary

• Serious mental health diagnosis (e.g., bipolar disorder or psychosis) assessed bystructured interview (M.I.N.I.)

• Currently engaged in evidence-based psychotherapy for Insomnia (i.e., CognitiveBehavioral Therapy) by self-report

• Failure to follow protocol (e.g., consistent "no show" for appointments, answeringquestionnaires dishonestly, refusal to complete more than 2 assessments [e.g., fMRIand Neuropsych])