Depression is a public health problem and common amongst adolescents. Cognitive behavioural therapy (CBT) is widely used to treat adolescent depression but existing research does not provide clear conclusions regarding the relative effectiveness of different delivery modalities.

The primary aim is to estimate the relative efficacy of different modes of CBT delivery compared with each other and control conditions for reducing depressive symptoms in adolescents. The secondary aim is to compare the different modes of delivery with regard to intervention completion/attrition (a proxy for intervention acceptability).

The Cochrane Depression, Anxiety and Neurosis Clinical Trials Register was searched in April 2020. MEDLINE, PsycInfo, EMBASE, four other electronic databases, the CENTRAL trial registry, Google Scholar and Google were searched in November 2020, together with reference checking, citation searching and hand-searching of two databases.

Randomised controlled trials (RCTs) of CBT interventions (irrespective of delivery mode) to reduce symptoms of depression in young people aged 10-19 years with clinically relevant symptoms or diagnosis of depression were included.

Screening and data extraction were completed by two authors independently, with discrepancies addressed by a third author. CBT interventions were categorised as follows: group CBT, individual CBT, remote CBT, guided self-help, and unguided self-help. Effect on depressive symptom score was estimated across validated self-report measures using Hedges' g standardised mean difference. Acceptability was estimated based on loss to follow-up as an odds ratio. Treatment rankings were developed using the surface under the cumulative ranking curve (SUCRA). Pairwise meta-analyses were conducted using random effects models where there were two or more head-to-head trials. Network analyses were conducted using random effects models.

Sixty-eight studies were included in the review. The mean age of participants ranged from 10 to 19.5 years, and on average 60% of participants were female. The majority of studies were conducted in schools (28) or universities (6); other settings included primary care, clinical settings and the home. The number of CBT sessions ranged from 1 to 16, the frequency of delivery from once every 2 weeks to twice a week and the duration of each session from 20 min to 2 h. The risk of bias was low across all domains for 23 studies, 24 studies had some concerns and the remaining 21 were assessed to be at high risk of bias. Sixty-two RCTs (representing 6435 participants) were included in the pairwise and network meta-analyses for post-intervention depressive symptom score at post-intervention. All pre-specified treatment and control categories were represented by at least one RCT. Although most CBT approaches, except remote CBT, demonstrated superiority over no intervention, no approaches performed clearly better than or equivalent to another. The highest and lowest ranking interventions were guided self-help (SUCRA 83%) and unguided self-help (SUCRA 51%), respectively (very low certainty in treatment ranking). Nineteen RCTs (3260 participants) were included in the pairwise and network meta-analyses for 6 to 12 month follow-up depressive symptom score. Neither guided self-help nor remote CBT were evaluated in the RCTs for this time point. Effects were generally attenuated for 6- to 12-month outcomes compared to posttest. No interventions demonstrated superiority to no intervention, although unguided self-help and group CBT both demonstrated superiority compared to TAU. No CBT approach demonstrated clear superiority over another. The highest and lowest ranking approaches were unguided self-help and individual CBT, respectively. Sixty-two RCTs (7347 participants) were included in the pairwise and network meta-analyses for intervention acceptability. All pre-specified treatment and control categories were represented by at least one RCT. Although point estimates tended to favour no intervention, no active treatments were clearly inferior. No CBT approach demonstrated clear superiority over another. The highest and lowest ranking active interventions were individual CBT and group CBT respectively. Pairwise meta-analytic findings were similar to those of the network meta-analysis for all analyses. There may be age-based subgroup effects on post-intervention depressive symptoms. Using the no intervention control group as the reference, the magnitudes of effects appear to be larger for the oldest age categories compared to the other subgroups for each given comparison. However, they were generally less precise and formal testing only indicated a significant difference for group CBT. Findings were robust to pre-specified sensitivity analyses separating out the type of placebo and excluding cluster-RCTs, as well as an additional analysis excluding studies where we had imputed standard deviations.

At posttreatment, all active treatments (group CBT, individual CBT, guided self-help, and unguided self-help) except for remote CBT were more effective than no treatment. Guided self-help was the most highly ranked intervention but only evaluated in trials with the oldest adolescents (16-19 years). Moreover, the studies of guided self-help vary in the type and amount of therapist support provided and longer-term results are needed to determine whether effects persist. The magnitude of effects was generally attenuated for 6- to 12-month outcomes. Although unguided self-help was the lowest-ranked active intervention at post-intervention, it was the highest ranked at follow-up. This suggests the need for further research into whether interventions with self-directed elements enable young people to maintain effects by continuing or revisiting the intervention independently, and whether therapist support would improve long-term outcomes. There was no clear evidence that any active treatments were more acceptable to participants than any others. The relative effectiveness of intervention delivery modes must be taken into account in the context of the needs and preferences of individual young people, particularly as the differences between effect sizes were relatively small. Further research into the type and amount of therapist support that is most acceptable to young people and most cost-effective would be particularly useful.

The high prevalence of depression among college students has a strong negative impact on individual physical and mental health, academic development, and interpersonal communication. This paper reviewed the extant literature by identifying nonpathological factors related to college students' depression, investigating the methods of predicting depression, and exploring nonpharmaceutical interventions for college students' depression. The influencing factors of college students' depression mainly fell into four categories: biological factors, personality and psychological state, college experience, and lifestyle. The outbreak of coronavirus disease 2019 has exacerbated the severity of depression among college students worldwide and poses grave challenges to the prevention and treatment of depression, given that the coronavirus has spread quickly with high infection rates, and the pandemic has changed the daily routines of college life. To predict and measure mental health, more advanced methods, such as machine algorithms and artificial intelligence, have emerged in recent years apart from the traditional commonly used psychological scales. Regarding nonpharmaceutical prevention measures, both general measures and professional measures for the prevention and treatment of college students' depression were examined in this study. Students who experience depressive disorders need family support and personalized interventions at college, which should also be supplemented by professional interventions such as cognitive behavioral therapy and online therapy. Through this literature review, we insist that the technology of identification, prediction, and prevention of depression among college students based on big data platforms will be extensively used in the future. Higher education institutions should understand the potential risk factors related to college students' depression and make more accurate screening and prevention available with the help of advanced technologies.

This meta-analysis investigated the effectiveness of universal mental health prevention programs for higher education students on a range of adjustment outcomes. A systematic literature search identified 103 controlled published and unpublished interventions involving college, graduate, or professional students. As hypothesized, skill-training programs that included a supervised practice component were significantly more effective overall (mean effect size = 0.45, confidence interval (CI) = 0.39 to 0.52) compared to skill-training programs without supervised practice (0.11, CI = -0.01 to 0.22) and psychoeducational (information-only) programs (0.13, CI = 0.06 to 0.21). When comparisons on specific outcomes were possible, skill-training programs including supervised practice were significantly more effective than the other two groups of programs in reducing symptoms of depression, anxiety, stress, and general psychological distress, and in improving social-emotional skills, self-perceptions, and academic behaviors and performance. The magnitude of effects achieved in several outcome areas is comparable to or higher than that reported in other reviews of universal programs, suggesting that skill-training programs for higher education students that incorporate supervised practice now join the ranks of other effective preventive mental health interventions. This review offers several recommendations to improve the experimental rigor of future research.

Suicide is a leading cause of death among post-secondary students worldwide. Suicidal thoughts and planning are common among post-secondary students. Previous reviews have examined the effectiveness of interventions for symptomatic individuals; however, many students at high risk of suicide are undiagnosed and untreated.

We evaluated the effect on suicide and suicide-related outcomes of primary suicide prevention interventions that targeted students within the post-secondary setting.

We searched the following sources up to June 2011: Specialised Registers of two Cochrane Groups, Cochrane Central Register of Controlled Trials, and nine other databases, trial registers, conference proceedings, and websites of national and international organizations. We screened reference lists and contacted authors of included studies to identify additional studies. We updated the search in November 2013; we will include these results in the review's next update.

We included studies that tested an intervention for the primary prevention of suicide using a randomized controlled trial (RCT), controlled before-and-after (CBA), controlled interrupted time series (CITS), or interrupted time series (ITS) study design. Interventions targeted students within the post-secondary setting (i.e. college, university, academy, vocational, or any other post-secondary educational institution) without known mental illness, previous suicide attempt or self-harm, or suicidal ideation. Outcomes included suicides, suicide attempts, suicidal ideation, changes in suicide-related knowledge, attitudes and behavior, and availability of means of suicide.

We used standardized electronic forms for data extraction, risk of bias and quality of evidence determination, and analysis. We estimated standardised mean differences (SMD) with 95% confidence intervals (CIs). We analysed studies by intervention type and study design. We summarized RCT effect sizes using random-effects models meta-analyses; and analysed statistical heterogeneity using the Chi(2) test and I(2) statistic. We described narratively the results from studies that used other study designs.

Eight studies met inclusion criteria. They were heterogeneous in terms of participants, study designs, and interventions. Five of eight studies had high risk of bias. In 3 RCTs (312 participants), classroom-based didactic and experiential programs increased short-term knowledge of suicide (SMD = 1.51, 95% CI 0.57 to 2.45; moderate quality evidence) and knowledge of suicide prevention (SMD = 0.72, 95% CI 0.36 to 1.07; moderate quality evidence). The effect on suicide prevention self-efficacy in one RCT (152 participants) was uncertain (SMD = 0.20, 95% CI -0.13 to 0.54; low quality evidence). One CBA analysed the effects of an institutional policy that restricted student access to laboratory cyanide and mandated professional assessment for suicidal students. The incidence of student suicide decreased significantly at one university with the policy relative to 11 control universities, 2.00 vs. 8.68 per 100,000 (Z = 5.90; P < 0.05). Four CBAs explored effects of training 'gatekeepers' to recognize and respond to warning signs of emotional crises and suicide risk in students they encountered. The magnitude of effect sizes varied between studies. Gatekeeper training enhanced short-term suicide knowledge in students, peer advisors residing in student accommodation, and faculty and staff, and suicide prevention self-efficacy among peer advisors. There was no evidence of an effect on participants' suicide-related attitudes or behaviors. One CBA found no evidence of effects of gatekeeper training of peer advisors on suicide-related knowledge, self-efficacy, or gatekeeper behaviors measured four to six months after intervention.

We found insufficient evidence to support widespread implementation of any programs or policies for primary suicide prevention in post-secondary educational settings. As all evaluated interventions combined primary and secondary prevention components, we were unable to determine the independent effects of primary preventive interventions. Classroom instruction and gatekeeper training increased short-term suicide-related knowledge. We found no studies that tested the effects of classroom instruction on suicidal behavior or long-term outcomes. Limited evidence suggested minimal longer-term effects of gatekeeper training on suicide-related knowledge, while no evidence was found evaluating its effect on suicidal behavior. A policy-based suicide intervention reduced student suicide, but findings have not been replicated. Our findings are limited by the overall low quality of the evidence and the lack of studies from middle- and low-income countries. Rigorously designed studies should test the effects of preventive interventions on important health outcomes, including suicidal ideation and behavior, in varying post-secondary settings.