The EQ-5D-Y-3L is a standardized instrument designed to measure health-related quality of life in children and adolescents. It consists of five dimensions, each rated on a 3-point scale: no problems, some problems, severe problems. It also includes a visual analogue scale (VAS) from 0 (worst imaginable health) to 100 (best imaginable health). Higher dimension scores indicate more health problems; higher VAS scores indicate better self-rated health. It is completed by adolescents.

The UCLA-8 is an 8-item scale designed for adolescents. Items are rated on a 4-point scale (1 = never to 4 = often). Higher scores indicate greater loneliness.

The APQ adolescent-report version measures perceptions of parenting behaviors. Items are rated on a 5-point scale from 1 (never) to 5 (always). Higher scores on involved and positive parenting subscales indicate better parenting practices.

The PSC-17 (adolescent-report) includes 17 items with a response range from 0 (never) to 2 (often), assessing overall psychosocial problems. Higher scores indicate more emotional and behavioral problems.

The WHO-5 includes 5 items rated from 0 (none of the time) to 5 (all of the time), assessing subjective well-being over the past 14 days. Scores range from 0 (lowest well-being) to 25 (highest well-being). Higher scores indicate greater well-being. It is completed by adolescents.

The RCADS (adolescent self-report) consists of 25 items, each rated on a 4-point Likert scale (0 = never, 1 = sometimes, 2 = often, 3 = always). Item responses are summed to create separate scores for anxiety, depression, and a total score. Higher scores indicate greater anxiety, depressive symptoms, and overall emotional problems.

The SEAL emotional regulation, problem-solving, interpersonal skills subscales include 7 items with responses "yes," "no," or "maybe." Higher scores indicate better socio-emotional skills. The questionnaire is completed by adolescents.

The HBSC bullying module captures both traditional and cyber forms of bullying, including victimization and perpetration, over the past couple of months. It consists of 4 items covering bullying others, being bullied, cyberbullying perpetration, and cyberbullying victimization. Each item is scored on a 5-point scale: 0 = not in the past couple of months, 1 = once or twice, 2 = 2-3 times a month, 3 = about once a week, 4 = several times a week. Higher scores indicate greater involvement in bullying or cyberbullying. It is completed by adolescents.

The Parent-Child Communication scale (adolescent-report) consists of 7 items assessing the adolescent's ability to communicate feelings, problems, and beliefs with their caregiver. Items are rated on a 5-point Likert scale from 1 (strongly disagree) to 5 (strongly agree). Higher scores indicate better communication between the adolescent and caregiver.

The MOS-SSS includes 18 items with a response range from 1 (none of the time) to 5 (all of the time). The emotional and affectionate subscales together comprise 11 items. Higher scores indicate greater perceived social support. It is completed by adolescents.

The APQ caregiver-report version measures frequency of disciplinary practices. Items are rated on a 5-point scale from 1 (never) to 5 (always). Higher scores on the corporal punishment subscale indicate greater use of punitive parenting practices. It is completed by caregivers.

This subscale consists of 5 items assessing psychologically aggressive behaviors toward the child in the past 4 weeks, including verbal aggression, emotional shaming, withdrawal, and threats of abandonment. Each item is scored on a 9-point frequency scale (0 = never to 8 = 8 or more times). Higher scores indicate greater frequency of emotional maltreatment.

The WHO-5 includes 5 items rated from 0 (none of the time) to 5 (all of the time), assessing subjective well-being over the past 14 days. Scores range from 0 (lowest well-being) to 25 (highest well-being). Higher scores indicate greater well-being. It is completed by caregivers.

The PHQ-9 is a 9-item self-report tool for depressive symptom severity. Items are scored from 0 (not at all) to 3 (nearly every day). Higher scores indicate more depressive symptoms. It is completed by caregivers.

The PSS is an 18-item self-report questionnaire rated on a 5-point Likert scale (1 = strongly disagree to 5 = strongly agree). Higher scores indicate greater parental stress. It is completed by caregivers.

The RULS-6 consists of 6 items rated on a Likert scale (from 1 = never to 4 = always). Item responses are summed to create a total score ranging from 6 to 24, with higher scores indicating greater loneliness. It is completed by caregivers.

The MOS-SSS emotional and affectionate subscales comprise 11 items. Scores range 1 (none of the time) to 5 (all of the time). Higher scores indicate more perceived social support. It is completed by caregivers.

The problem solving subscale (6 items) assesses ability to resolve problems. Responses range from 1 (strongly agree) to 4 (strongly disagree). Higher scores indicate poorer functioning. It is completed by caregivers.

The OxCAP-MH includes 16 items across domains such as social participation, emotional stability, and access to resources. Items are scored on a 5-point Likert scale. It is completed by caregivers.

The PECUNIA RUM assesses caregivers' use of residential care, non-residential health and social care, informal help, and work-related resources.

The PECUNIA RUM proxy for adolescents records service use reported by caregivers, covering residential care, non-residential health and social care, and education.

The Parent-Child Communication Scale (caregiver-report) includes 7 items assessing caregiver perceptions of openness, emotional expressiveness, problem discussion, and perspective-taking in communication with their child. Items are rated on a 5-point Likert scale (1 = strongly disagree to 5 = strongly agree). Total scores range from 7 to 35. Higher scores indicate more open, emotionally supportive, and bidirectional communication.

The PSC-17 (caregiver-report) includes 17 items with a response range from 0 (never) to 2 (often), assessing overall psychosocial problems. The externalizing and attention subscales include 12 items. Higher scores indicate more emotional and behavioral problems.

The short form of the PCL-5 includes 4 items assessing PTSD symptom severity. Each item is scored from 0 (not at all) to 4 (extremely), with higher scores indicating greater PTSD symptoms. It is completed by caregivers.

The WHO-5 is a brief measure of emotional well-being over the past 14 days. It includes 5 items scored from 0 (none of the time) to 5 (all of the time). Total scores range from 0 (absence of well-being) to 25 (maximum well-being). Higher scores indicate greater well-being. It is completed by intervention staff.

The PLH-FAT evaluates fidelity of intervention delivery based on facilitator performance. It yields percentage scores on completion of intervention activities and demonstration of intervention skills. Higher percentages indicate greater fidelity.

Intervention costs will include personnel time for training and delivery, organizational costs, materials, transportation, and consumables.

The TPA allows caregivers to identify their adolescent's three most pressing emotional or behavioral problems and rate each on a scale from 0 (not a problem) to 4 (a very big problem). Higher scores indicate greater severity of caregiver-identified problems.

The TPA allows adolescents to identify their three most important problems and rate each on a scale from 0 (not a problem) to 4 (a very big problem). Higher scores indicate greater severity of self-identified problems.

Attendance will be assessed for: individual attendance, defined as the percentage of PLH sessions out of six attended separately by adolescents and caregivers; family attendance, defined as the percentage of PLH sessions out of six attended jointly by both adolescent and caregiver; and catch-up attendance, defined as the percentage of scheduled catch-up sessions attended out of six. Higher percentages indicate greater attendance.

Enrollment will be assessed as: individual enrollment, measured as the percentage of adolescents and caregivers who attended at least one PLH session; family enrollment, measured as the percentage of families in which both the adolescent and caregiver attended at least one PLH session. Higher percentages indicate greater enrollment.

The APQ is a self-report instrument of parenting practices. The involved and positive parenting subscales each assess positive caregiver behaviors such as engagement, attention, and supportive interactions. Items are rated on a 5-point scale ranging from 1 (never) to 5 (always). Higher scores indicate more positive and involved parenting practices.

The CRIES includes 8 items, scored on a 4-point scale (0 = not at all, 1 = rarely, 3 = sometimes, 5 = often). It provides a total score and two subscales: intrusion and avoidance. Higher scores indicate greater trauma-related distress. It is completed by adolescents.

The FIES consists of 8 items assessing household experiences of food insecurity in the past 12 months, from worry about food availability to skipping meals or going a whole day without eating due to lack of money or resources. Items are scored yes (1) or no (0). Higher scores indicate more severe food insecurity. It is completed by caregivers.