Effects of Group-based and Digitally Delivered CBT-I in Youth

Insomnia symptoms measured by Insomnia Severity Index (ISI). ISI is a 7-item self-rated scale. Possible scores range from 0 to 28, with higher scores indicating higher insomnia severity.

Pittsburgh Sleep Quality Index (PSQI) is a self-rated scale consisting of 19 questions. All items are combined to form seven component scores on different aspects of sleep quality, each of which ranges from 0 to 3 points with higher scores representing more sleep disturbance. The seven component scores are added to one global score, which ranges from 0 to 21, with higher scores indicating more difficulties with sleep.

Daily sleep diary for consecutive seven days. Sleep parameter estimated by daily sleep diary: time in bed (TIB) in hours

Daily sleep diary for consecutive seven days. Sleep parameter estimated by daily sleep diary: total sleep time (TST) in hours

Daily sleep diary for consecutive seven days. Sleep parameter estimated by daily sleep diary: sleep onset latency (SOL) in mins

Daily sleep diary for consecutive seven days. Sleep parameter estimated by daily sleep diary: wake after sleep onset (WASO) in mins

Daily sleep diary for consecutive seven days. Sleep parameter estimated by daily sleep diary: sleep efficiency (SE), which is calculated by total sleep time divided by total time in bed, %

Actigraphic assessment for consecutive seven days. Sleep parameter estimated by wrist actigraphy: time in bed (TIB) in hours

Actigraphic assessment for consecutive seven days. Sleep parameter estimated by wrist actigraphy: total sleep time (TST) in hours

Actigraphic assessment for consecutive seven days. Sleep parameter estimated by wrist actigraphy: sleep onset latency (SOL) in mins

Actigraphic assessment for consecutive seven days. Sleep parameter estimated by wrist actigraphy: wake after sleep onset (WASO) in mins

Actigraphic assessment for consecutive seven days. Sleep parameter estimated by wrist actigraphy: sleep efficiency (SE), which is calculated by total sleep time divided by total time in bed, %

Children's Depression Rating Scale (CDRS-R) is a 17-item rating scale based on a semistructured interview with children. Possible scores range from 17 to 113, with higher scores indicating severer depressive symptoms.

Hospital Anxiety and Depression Scale (HADS) is a self-assessed scale for detecting states of depression and anxiety. The depression subscale range in scores from 0 to 21, with higher scores indicating severer states of depression. Similarly, the anxiety subscale range in scores from 0-21 with higher scores indicating severer states of anxiety. No additional computation will be made with the two subscores.

Depression Anxiety Stress Scales consists of three self-report scales designed to measure the emotional states of depression, anxiety and stress. Each of the three DASS scales contains 14 items. Higher scores suggest more depression, anxiety and stress, respectively.

Beck's Depression Inventory (BDI) consists of 13 self-report items designed to measure depressive symptoms. Higher scores suggest high level of depression

The World Health Organisation- Five Well-Being Index (WHO-5) consists of 5 self-report items designed to measure subjective well-being. Higher scores indicate better well-being.

Dysfunctional Beliefs and Attitudes about Sleep (DBAS) is a 16-item self-rated scale measuring the respondent's sleep-related beliefs, more specifically, their expectations and attitudes regarding the causes, consequences, and potential treatments of sleep issues. A total score is calculated by averaging score of all items, possibly scored 0 to 10, with a higher score indicating more dysfunctional beliefs and attitudes about sleep.

Sleep Hygiene Practice Scale (SHPS) is a 30-item self-rated scale measuring sleep hygiene behaviors, ranging in total scores from 30 to 180, with higher scores indicating lower levels of sleep hygiene.

Pre-Sleep Arousal Scale is a 16-item self-rated scale measuring pre-sleep arousal. There are two subscales on the cognitive and somatic manifestations of arousal, with eight items in each subscale (possibly scored from 8 to 40). In both cases, a higher score indicates higher pre-sleep arousal.

Ford Insomnia Response to Stress Test (FIRST) consists of 9 items designed to measure sleep reactivity. Possible scores range from 9 to 36. A higher score indicates higher sleep activity.

Depressive Symptom Inventory Suicidality Subscale (DSI-SS) is a 4-item self-rated scale measuring suicidal ideation. Possible total scores range from 0 to 12, with higher scores indicating higher suicidal ideation.

Paediatric Daytime Sleepiness Scale (PDSS) is an 8-item self-rated scale measuring daytime sleepiness, ranging in total scores from 0 to 32 with higher scores indicating more sleepiness.

Multidimensional Fatigue Inventory (MFI) is a 20-item self-rated scale on fatigue symptoms. There are three subscales, measuring the physical (possibly scored from 7 to 35), mental (possibly scored from 6 to 30), and spiritual (possibly scored from 7 to 35), dimensions of fatigue. A grand total score can be calculated by summing up the three sub scores. In all cases, a higher score represents higher fatigue symptoms.

KIDSCREEN-27 is a 27-item self-rated scale measuring health related quality of life measure for children and adolescents. There are five subscales on: physical well-being (possibly scored from 5 to 25), psychological well-being (possibly scored 7 to 35), autonomy & parents (possibly scored 7 to 35), peers & social support (possibly scored 4 to 20), and school environment (possibly scored 4 to 20). A grand total score can be calculated by summing up the five sub scores. In all cases, a higher score represents higher perceived well-being.

Clinical Global Impression (CGI) Scale is a clinician-rated scale, comprised of two one-item subscales: Severity of Illness (CGI-S) subscale evaluating the severity of psychopathology, and Clinical Global Improvement Scale (CGI-I) evaluating change from the initiation of treatment. In both cases, the score is given on a seven-point scale, with higher values indicating higher severity of illness and larger improvement respectively.

Trail Making Test for assessing visual attention and task switching. In Trail Making Test, longer reaction time indicates lower level of attention.

Go/No-go Task for assessing inhibitory ability. In Go/No-go Task, a higher error rate indicates lower inhibition control.

Digit Span Task for assessing working memory capacity. In Digit Span Task, a higher number of recalled digits indicates better working memory.

N-back Task for assessing working memory capacity and manipulation. In N-back Task, a d prime score will be calculated based on the signal detection theory, where a higher score indicates better working memory performance.

Chinese Auditory Verbal Learning Task for assessing episodic memory, where a higher number of recalled words indicates better episodic memory performance.

Wisconsin Card Sorting Test for assessing problem solving. In Wisconsin Card Sorting Test, lower executive functioning is indicated by a higher percentage of persistent errors and a higher number of trials taken to complete the first category.

Sleep-related Dot-Probe Task for assessing sleep-related attention bias. In the Sleep-related Dot-probe Task, a higher attention bias score indicates higher vigilance towards sleep-related stimuli.

Balloon Analogue Risk Task for assessing risk-taking and decisionmaking. In Balloon Analogue Risk Task, a score will be calculated by averaging the number of pumps on unexploded blue balloons, where a higher score indicates more risk-taking and impulsive propensities.

Suicide Implicit Association Test (IAT) for assessing implicit cognition of suicide or death. In the Suicide Implicit Association Test, positive D-scores indicate stronger implicit identification with death and negative D scores indicate stronger implicit identification with life

Difficulties in Emotion Regulation Scale (DERS) is a 36-item self-reported scale measuring emotion regulation problems. Every item uses a 1-to-5 Likert scale, with 1 represents "Almost never" and 5 represents "Almost always". Total score ranges from 36 to 180. Higher score represents higher difficulties in regulating emotions. Sub-scores will also be calculated on the following subscales:

i. Nonacceptance of emotional responses ii. Difficulty engaging in goal-directed behavior iii. Impulse control difficulties iv. Lack of emotional awareness v. Limited access to emotion regulation strategies vi. Lack of emotional clarity

Emotion regulation questionnaire - frequency/capacity (ERQ-f/ERQ-c) is a 28-item scale designed to measure respondents' tendency/capacity to regulate their emotions in three ways: (1) Cognitive Reappraisal, (2) Expressive Suppression and (3) Distraction. Scores will be calculated separately for each subscale, ranging from 4 to 42. Each item will be answered on a 7-point Likert-type scale ranging from 1(strongly disagree) to 7 (strongly agree). For ERQ-f, higher score represents higher frequency of using certain regulation method. For ERQ-c, higher score represents higher capacity of using certain regulation method.

Emotion regulation task is a paradigm used to examined subjects' ability/efficiency in using different emotion regulation strategies (i.e., watch, reappraisal and distraction). Subject will first see a negative or neutral picture, followed by instructions on using which strategy to regulate their emotions induced by the picture (watch, reappraisal or distraction). There are four conditions: neutral-watch, negative-watch, negative-reappraisal, negative-distraction. After each picture, subjective emotional valence and arousal ratings (ranging from 1-9) will be collected. To examine the subjects' different emotion regulation ability, valence and arousal ratings will be analysed by comparing different conditions, groups, and time (pre/post-treatment).

Category Fluency Task will be used to assess verbal fluency. The total number of words produced will be summed and transformed into z-scores in comparison to local norms