Effects of Cognitive Behavioural Therapy and Bright Light Therapy for Insomnia in Adolescents With Evening Chronotype

Insomnia is prevalent in adolescents. Together with an increase of evening preference (i.e. evening chronotype) in adolescent, sleep disturbance in adolescents are associated with a constellation of adverse outcomes. Insomnia and evening chronotype in adolescents are also found to predict the development of mental health problems and negative health-related outcomes in young adulthood.

While cognitive behavioural therapy for insomnia (CBT-I) and bright light therapy were evidenced to be effective in managing sleep problems in adults, there is limited evidence to support their efficacy in children and adolescents. To address the limitations in the existing literature, this study aims to conduct a randomised controlled trial to examine the effects of CBT-I and light therapy on insomnia and mood symptoms, and other clinical and daytime symptoms, as well as overall functioning in adolescents with insomnia (particularly sleep onset insomnia) and evening chronotype.

A randomised, assessor-blind, parallel group controlled trial will be conducted in youth with insomnia and eveningness. Eligible participants will be randomised to one of the following groups: CBT-I, CBT-I plus bright light therapy, or waiting-list control. Randomisation will be carried out using an automated online system. Assessments will be conducted at pre-treatment (week 0), during the treatment (week 2 \& 4) and post-treatment (week 6/at the conclusion of the last group session). The two active treatment groups will be additionally followed up at post-treatment one-month and post-treatment six months in order to examine the maintenance effects following the intervention with CBT-I and CBT-I plus bright light therapy respectively.

Eligibility Criteria:
Inclusion Criteria:

1. Chinese aged 12-24 years old;
2. Predominant complaint of difficulty in initiating sleep at least three times a week and for at least 3 months;
3. Show clinically significant impairment / distress;
4. Having a score of \>= 9 on the Insomnia Severity Index (ISI) ;
5. Classified as evening chronotype based on the score of reduced Horne-Östberg Morning-Eveningness Questionnaire (rMEQ; i.e. \<12) and having a sleep onset time of 11:15pm or later for 12 year olds, 11:30pm or later for 13-14 year olds, and 12:00am or later for 15 years or above at least 3 nights per week for the past 3 month as confirmed by a 7-day sleep diary;
6. Written informed consent of participation into the study is given by the participant and his/her parent or guardian (for those aged under 18);
7. Being able to comply with the study protocol.

Exclusion Criteria:

1. Current diagnosis of substance abuse or dependence; current or history of manic or hypomanic episode, schizophrenia spectrum disorders, neurodevelopmental disorders, organic mental disorders, or intellectual disabilities;
2. Having a prominent medical condition known to interfere with sleep continuity and quality (e.g. eczema);
3. Having a clinically diagnosed sleep disorder that may potentially contribute to a disruption in sleep continuity and quality (e.g. narcolepsy) as ascertained by the Structured Diagnostic Interview for Sleep Patterns and Disorder (DISP);
4. Concurrent, regular use of medications known to affect sleep continuity and quality;
5. Initiation of and change of medication that may interfere with circadian rhythm within past 3 months (e.g. lithium);
6. In the opinion of the research clinician, having a clinically significant suicidality (presence of suicidal ideation with a plan or an attempt);
7. Currently receiving any other structured psychotherapy;
8. With hearing or speech deficit;
9. Presence of an eye disease (e.g. retinal blindness);
10. Night shift worker;
11. Trans-meridian flight in the past 3 months and during the study.