Evaluating the Effectiveness of a School-based Stepped Care Treatment Model for Adolescent Depression in Pakistan

Depressive symptoms will be measured using the Patient Health Questionnaire (PHQ-9) for adolescents, a 9-item instrument rated on a 4-point Likert scale. The total score ranges from 0 to 27, with higher scores indicating greater severity of depressive symptoms (worse outcome) over the past 2 weeks. The PHQ-9 has been previously adapted and validated in Pakistan and has demonstrated high internal consistency (Cronbach's α = 0.83).

The PSC is a 35-item screening scale comprising three subscales: internalizing, externalizing, and attention problems. Items are rated on a 3-point scale, with total scores ranging from 0 to 70. Higher scores indicate greater psychosocial difficulties (worse outcome). The Urdu version of the PSC has been adapted and validated in Pakistan and has demonstrated good reliability and validity.

This is a 25-item instrument rated on a 4-point Likert scale, with a total transformed score ranging from 0 to 100, used to measure levels of anxiety and low mood. The instrument comprises two subscales (anxiety and depression). Higher scores indicate greater symptom severity (worse outcome). The measure has been adapted and used successfully in Pakistan.

The DSM-5 Level 1 Cross-Cutting Symptom Measure is a self-rated screening instrument that assesses mental health domains relevant across psychiatric diagnoses. It is used to identify additional areas of inquiry that may have a significant impact on the child's treatment and prognosis. Items are rated on a 5-point Likert scale, with higher scores indicating greater symptom severity (worse outcome) over the past 2 weeks.

The Checklist of Somatic Symptoms of Distress is a 10-item instrument rated on a 3-point Likert scale, with total scores ranging from 0 to 20, used to assess somatic symptoms of distress. Higher scores indicate greater somatic symptom severity (worse outcome). The measure has been previously adapted and used in Pakistan.

Experience of bullying in the past 30 days will be measured using a contextualised version of the Bullying Victimization Questionnaire. The total score ranges from 0 to 12, with higher scores indicating greater levels of peer victimisation (worse outcome).

Change in school climate, including students' relationships with teachers, sense of belonging with the school and peers, commitment to school tasks, and participation in school activities, will be measured using an adapted version of the Beyond Blue School Climate Questionnaire (BBSCQ). The questionnaire consists of 28 items, each rated on a 4-point Likert scale, with total scores ranging from 0 to 84. Higher scores indicate a more favourable perception of the school climate (better outcome). The measure will be administered to both adolescents and their caregivers.

Academic performance and classroom attendance will be assessed using official school records, which have been previously used by the investigators in Pakistan. Annual academic performance will be recorded as percentage scores (0-100), with higher scores indicating better academic performance (better outcome). Classroom attendance will be recorded as the percentage of days attended during the academic year (0-100%), with higher percentages indicating better attendance (better outcome).

The Short Warwick-Edinburgh Mental Wellbeing Scale (SWEMWBS) is a 7-item self-report measure assessing mental wellbeing, focusing on positive functioning of thoughts and feelings over the past two weeks. Items are rated on a 5-point Likert scale ranging from "none of the time" to "all of the time." Total scores range from 7 to 35, calculated by summing item responses. Higher scores indicate better mental wellbeing (better outcome).

The Self-Reporting Questionnaire (SRQ) will be used to assess psychological distress, represented by subscales of physical symptoms and emotional symptoms. Items are scored 0 or 1, where a score of 1 indicates the presence of a symptom of psychological distress. Total scores range from 0 to 20, with higher scores indicating greater psychological distress (worse outcome).

Parenting practices will be assessed using the Positive Involvement subscale of the Alabama Parenting Questionnaire (APQ). This subscale assesses the extent to which parents engage positively with their children, including friendly communication, involvement in planning and conducting activities, awareness of children's free-time activities, playing games together, helping with homework, interest in day-to-day plans, and knowledge of children's friends. Items are rated on a Likert scale, with higher scores indicating greater positive parental involvement (better outcome).

Child insight into problems and wellbeing will be measured using the self-administered PSYCHLOPS-Kids. The measure assesses three domains: problems, functioning, and wellbeing. PSYCHLOPS-Kids has three versions (pre-therapy, during-therapy, and post-therapy). In this study, the pre-therapy and post-therapy versions will be used as part of the assessment. Domain and total scores are calculated by summing item responses, with higher scores indicating greater problems and poorer wellbeing (worse outcome).

Global functioning will be assessed using a brief clinician-rated measure that rates adolescents on a scale from 1 to 100, categorised into ten functioning bands. Scores range from 1-10 (indicating severe impairment) to 91-100 (indicating superior functioning). Higher scores indicate better global functioning (better outcome).

This is a 25-item instrument rated on a 5-point Likert scale (0-4), used to assess social problem-solving skills, including positive problem orientation, negative problem orientation, rational problem solving, impulsivity-carelessness style, and avoidance style. Total scores are calculated by summing item responses (possible range 0-100). Higher scores indicate better social problem-solving skills (better outcome).

Perceived emotional support will be assessed using a measure rated on a 4-point Likert scale, with scores ranging from 1 to 4, to assess the level of emotional support perceived by the child across three relationship categories: family members, non-family adults, and friends. Higher scores indicate higher levels of perceived emotional support (better outcome).

Health service utilisation will be assessed using a structured measure to collect information on outpatient and inpatient healthcare services used by adolescents over a period of up to 9 months, including contacts with all types of healthcare providers. Higher values indicate greater health service utilisation.