Table 3 Study characteristics of excluded studies that satisfied part of the inclusion criteria

Randomized trials

 Guo 2017 USA [59]

Cluster RCT to examine the effects of universal depression screening

Elementary school setting involving seventh and eighth grade Asian American and Latino students

Intervention: Universal depression screening using the Patient Health Questionnaire for Adolescents (PHQ-A)

Control: No mental health screening

Referral, acceptance, and receipt of care

No primary outcomes related to mental health reported. The study evaluated school-based mental health service referrals, caregiver consent for services, and treatment initiation.

 Mahoney 2017 USA [64]

Multisite RCT to understand the internal barriers of implementing a targeted preventive intervention, CATCH-IT

Adolescents between the ages of 13 and 18

Intervention: CATCH-IT, a 14-module Internet-based depression prevention intervention that involves mental health screening and depression prevention treatment.

Control: General health education

Internal barriers to successful implementation using REACH framework (proportion of target audience exposed to intervention)

Focused on barriers to implementing a preventive intervention and included those with either a past major depressive disorder diagnosis or a CES-D score of 8 to 17.

 Mirzaie 2019 Afghanistan [63]

Sought to validate the Maria Kovacs Children’s Depression Inventory to assess depression.

High school students in Afghanistan (grades 7 to 9)

Intervention: Maria Kovacs children’s depression inventory

Control: Beck’s depression Inventory

Validity, reliability, sensitivity, specificity, and positive and negative predictive values

Both groups were offered screening tools and limited information was provided on the included students.

 Rinke 2019  USA [60]

Stepped-wedge cluster RCT of quality improvement collaborative (QIC)

Pediatric primary care clinics including health care providers trained in quality improvement and diagnoses of adolescent depression

Intervention: Quality improvement collaborative

Control: No attempt for quality improvement

Frequency of recognition and diagnosis of adolescent depression

Information on participant characteristics limited, therefore, unclear whether study included participants with characteristics that were part of our exclusion criteria. The study did not report a pre-defined cut-off score to identify patients who may have depression.

 Sterling 2018 USA [61]

Pragmatic cluster randomized implementation and effectiveness trial on delivering Screening and Brief Intervention and Referral to Treatment (SBIRT)

Adolescents (age 12 to 18) who screened positive in a general pediatric primary care clinic

1^st arm: Pediatrician-only, in which pediatricians were trained to delivery SBIRT

2^nd arm: embedded behavioural clinician (BC), in which pediatricians refer eligible adolescents to a BC who administered SBIRT

Control: Usual care

Substance use and depression measures

Focused on identifying and delivering early intervention and treatment services to individuals at risk of developing substance use disorders and those who have already developed these disorders. Included adolescents who endorsed substance use or depression symptoms or were eligible for further assessments.

 Thabrew 2019 New Zealand [62]

RCT to compare the performance and acceptability of YouthCHAT screening and HEEADSSS assessment

13-year-old high school students attending a nurse-led clinic

Intervention: YouthCHAT, a depression screening tool based on the PHQ-A

Control: HEEADSSS, assessment, a psychosocial interview-based assessment to identify mental health and substance use problem.

Completion times, detection rates, and acceptability

Both groups received depression screening or assessment. There was no control group who received no depression screening.

Non-randomized trials

 Carrozzino 2016 Italy [65]

Clinimetric validation analysis of the Kellner Symptom Questionnaire and the Screen for Children Anxiety Related Emotional Disorders (SCARED) scales for depression and anxiety screening in adolescents

Adolescents with epilepsy, using participants without epilepsy as the control group.

Group: Patients with epilepsy

Control: Patients without history of epilepsy disorder or any diagnosis of neurological disease or chronic medical illness

Validity, reliability, and frequency of recognition and diagnosis of adolescent depression

Validation study. There was no control group who received no depression screening. Did not exclude those who had a history of depression or who were already under treatment.

 Harder 2019 USA [66]

Quality improvement study to evaluate the impact of a quality improvement learning collaborative on adolescent depression screening.

Medical files from seventeen pediatric serving (pediatric and family medicine) practices.

Group: Practices voluntarily participated in quality improvement initiative Control: Practices did not participate in the quality improvement initiative

Frequency of screening and documenting of initial plans of care

Not a depression screening study. No control group who did not receive depression screening. No information was reported on the adolescent population and limited information on the control group.