BackgroundMajor depressive disorder (MDD) is highly prevalent in youth. Conventional treatment paradigms primarily involve selective serotonin reuptake inhibitors (SSRIs) and psychotherapy, yet a significant proportion of this population exhibits treatment-resistant depression (TRD). In adults, interventional therapies like Electroconvulsive Therapy (ECT), repetitive Transcranial Magnetic Stimulation (rTMS), and ketamine have shown promise for TRD, but their comparative efficacy remains underexplored in Adolescent and pediatric population. This systematic review and meta-analysis aims to assess the relative effectiveness of ECT, rTMS, and ketamine in treating TRD among adolescents. MethodsFollowing PRISMA guidelines, we systematically searched databases for studies of ECT, rTMS, or ketamine for treatment-resistant depression in youth ages 10–24. Three reviewers independently screened for inclusion based on predefined criteria. Included observational and randomized controlled trials reported depression symptoms with measures like HDRS and MADRS in youth treated with ECT, rTMS, or ketamine. Two reviewers extracted data on interventions, patients, and depression symptom outcomes. Chance-adjusted inter-reviewer agreement was calculated. For meta-analysis, we pooled standardized mean differences (SMDs) in depression scores using random effects models and assessed heterogeneity with I2 statistics. ResultsMeta-analysis of 10 observational studies examined SMD in depression scores for treatment resistant depression patients treated with ECT, ketamine, or rTMS. Patients treated with ECT had a significantly lower SMD of 1.99 (95 % CI 0.92–3.05, p < 0.001) compared to baseline. Patients treated with ketamine also had a significantly lower SMD of 1.58 (95 % CI 1.04–2.12, p < 0.001). Patients treated with rTMS had the lowest SMD of 2.79 (95 % CI 0.79–4.80, p = 0.006). There was no significant difference between the three groups overall (p > 0.05). Comparative analysis between ECT and ketamine found no significant difference in SMD (p = 0.387). Comparison of ECT versus rTMS found a significant difference in SMD favoring rTMS (p = 0.004). Comparison of ketamine versus rTMS suggested a potential difference in SMD favoring rTMS (p = 0.058). In summary, rTMS resulted in significantly larger reductions in depression scores than ECT, and potentially larger reductions than ketamine. ConclusionsThis meta-analysis illustrates the ability of rTMS, ECT, and ketamine to improve depression in youth. rTMS resulted in the largest improvements, highlighting its potential as a first-line treatment for pediatric treatment-resistant depression given its favorable side effect profile compared to ECT. Further research directly comparing these modalities is needed.