Inclusion Criteria:
* Age 14-18 years old (assessed via review of unit census).
* Recent psychiatric hospitalization due to suicide risk (i.e., suicide attempts, aborted/interrupted attempts, or suicide ideation with intent and/or a plan): assessed using an abbreviated version of the Columbia Suicide Severity Rating Scale (C-SSRS). In terms of recency, adolescents will need to enroll in the baseline assessment within three months of discharge from the hospital in order to assess the high-risk post-hospitalization period.
* Clinically significant insomnia symptoms: consistent with prior trials using the SleepioTM package, participants will be screened using the Sleep Condition Indicator (SCI)-an 8-item measure created by SleepioTM treatment developers to screen for DSM-5 insomnia disorder. The SCI assesses sleep duration, quality, and difficulties, and daytime impairment due to sleep problems; lower scores on the SCI indicate poorer sleep conditions and a cutoff of ≤16 indicates probable insomnia disorder, which will be the cutoff used for the current study.
* Motivation to engage in sleep treatment: consistent with other trials testing SleepioTM, questions will be used to assess perception of sleep problem severity and desire to change. The scale includes (1) "At present, sleep is a big problem for me" and (2) "I want to change my sleep" rated on a scale 0=strongly disagree to 10=strongly agree. Each item must be rated ≥5, in line with prior trials. Given this is a digital intervention, this criterion will help ensure we recruit adolescents who are likely to engage with treatment. Importantly, we note that prior trials have not needed to exclude anyone based on this criterion, reflecting the idea that the majority of participants we encounter will be motivated to engage in this novel treatment.
Exclusion Criteria:
Prior CBT-I treatment (the intervention being tested in this study): prior treatment would indicate non-response to a reasonable dose of this empirically supported treatment.
* At high risk for obstructive sleep apnea (OSA): The STOP-BANG sleep apnea screening questionnaire (modified for adolescents) will be used to screen adolescents at high risk for OSA, who will be referred for a non-study polysomnography screening.
* Bipolar disorder: given concerns that certain components of CBT-I (i.e., sleep restriction) may be risky for this population.
* Substance use disorder that is primary to insomnia: significant substance use (alcohol or drug) disorders would require alternative treatment.
* Presence of factors that may reduce participant's ability to provide assent/consent or to complete the study procedures (e.g., non-English speaking, severe cognitive impairment, pervasive developmental disorder, acute psychosis, risk for other-directed violence).
* Unwillingness to wear the actigraphy device or to complete smartphone-based EMA at the time of enrollment: consistent with the research team's prior studies, if participants are actively enrolled in the study and then decide that they no longer want to wear the wrist actigraphy device, we will give them the option to continue only the SleepioTM and smartphone-based EMA parts of the study. • Not having a parent/legal guardian willing to provide permission (if adolescent is a minor) or consent (for their own participation): although permission is only required for minors, parents will be included for all adolescents to keep study procedures consistent for all participants.
