Abstract: Fourteen trials (590 participants) were included. No overall difference was found for the primary outcome of response to treatment compared with placebo (risk ratio (RR) 1.07, 95% confidence interval (CI) 0.91 to 1.26; 9 trials, N = 454). There was a small reduction in depression symptoms (standardised mean difference (SMD) -0.32, 95% CI -0.59 to -0.04; 13 trials, N = 533), but the evidence was of low quality. Subgroup analyses suggested a small reduction in depression symptoms among adolescents (SMD -0.45, 95% CI -0.83 to -0.007), and negligible change among children (SMD 0.15, 95% CI -0.34 to 0.64). Treatment with a tricyclic antidepressant caused more vertigo (RR 2.76, 95% CI 1.73 to 4.43; 5 trials, N = 324), orthostatic hypotension (RR 4.86, 95% CI 1.69 to 13.97; 5 trials, N = 324), tremor (RR 5.43, 95% CI 1.64 to 17.98; 4 trials, N = 308) and dry mouth (RR 3.35, 95% CI 1.98 to 5.64; 5 trials, N = 324) than did placebo, but no differences were found for other possible adverse effects. Wide CIs and the probability of selective reporting mean that there was very low-quality evidence for adverse events. There was heterogeneity across the studies in the age of participants, treatment setting, tricyclic drug administered and outcome measures. Statistical heterogeneity was identified for reduction in depressive symptoms, but not for rates of remission or response. As such, the findings from analyses of pooled data should be interpreted with caution. We judged none of these trials to be at low risk of bias, with limited information about many aspects of risk of bias, high dropout rates, and issues regarding measurement instruments and the clinical usefulness of outcomes, which were often variously defined across trials. Data suggest tricyclic drugs are not useful in treating depression in children. There is marginal evidence to support the use of tricyclic drugs in the treatment of depression in adolescents.

Plain-language summary: This review contained 14 trials (with 590 participants) and tested the effectiveness of tricyclic drugs against placebo. Trial data were available for amitriptyline, desipramine, imipramine and nortriptyline. Based on nine trials (454 participants), there was no evidence that tricyclic drugs lead to higher rates of remission or response than placebo. Based on 13 of the trials (533 participants), there was evidence that people treated with a tricyclic drug had lower depression severity scores than those on placebo, however, the size of this difference was small. Consistent with their known mechanism of action, tricyclic drugs were more likely than placebo to cause vertigo, symptoms of lowered blood pressure, tremor and dry mouth. Subgroup analyses of six trials involving only adolescents (239 participants) and two trials involving only children (77 participants) found no evidence of differential rates of remission or response between the age groups. In contrast, there was lowering of depression scores in eight trials involving only adolescents (414 participants) and no lowering of depression scores in three trials involving only children (64 participants). Most of the included studies were conducted in the era before standard methods for conducting treatment trials for depression in children and adolescents came about. There were considerable differences between the studies with regards to the clinical tools and methods used in assessment of improvement. Most trials were small. Only two trials produced a definitive result for depressive symptoms, and no trial produced a definitive result for response or remission. There was typically insufficient information to judge the quality of the trials accurately. With these limitations, it is difficult to answer questions about the effectiveness and safety of tricyclic drugs for treating depression in children and adolescents. Current evidence suggests that the situation is much the same for newer-generation antidepressants. Clinicians need to provide accurate information to children and adolescents, and their families, about the uncertainties regarding the benefits and risks of antidepressants as a treatment option for depression. Tricyclic drugs do not seem useful for treating children before puberty, and are, at most, of moderate benefit for adolescents.