Common Mental Disorders represent a severe burden for health, society and economy. Several psychotherapies have shown their efficacy on treating Common Mental Disorders using randomized clinical trials. Psychotherapies that are not supported by research evidences are disenfranchised and marginalized. A way to obtain recognition as Empirically Supported Treatment relies on systematic replication of single-case designs and on the aggregation of results through a meta-analysis. The purpose of this meta-analytic review was synthesizing single-case research on Transactional Analysis (TA) treatment for depression. Specifically, the effect of TA treatment for depression was examined in 11 studies published between 2012 and 2017. Results indicated that, on average, TA psychotherapy for depression had a large effect on depressive symptoms, g = 0.89, 95% confidence interval (CI) [0.29, 1.50]. Implications for future research on TA manualized treatment for specific Common Mental Disorders are discussed.
