Mood disorders (MDs) affect more than 300 million people. They are the third leading causes in 2017 of years lived with disability. Currently, pharmacotherapy represents the first-line option, but growing evidence suggests that although it is effective in the treatment of acute episodes, medication alone does not help many patients to achieve a functional recovery. However, despite it being established that psychotherapies are effective in treating MDs, there is still much to improve in our understanding, management, and treatment of MDs. Waiting for progress in personalized psychiatric treatment approaches that could lead to precise biological and psychosocial interventions, the treatment of MDs remained, to a large extent, “subjective clinical exercise.” Implementing evidence-based assessment (EBA) and treatment for MD is essential to reduce their burden at an individual, societal and public health levels. An efficient assessment process is essential because it leads to more accurate diagnosis, better treatment matching, increased patient engagement, and enhanced outcomes. When deciding how to conduct such EBA, the clinician has to consider the target content for the assessment, the function that the assessment could serve in the treatment context, and the different candidate assessments available. This project has three main goals: (1) to develop and evaluate (pilot study) an EBA approach to individual psychotherapy that is valid and easy enough to be administered routinely in real-world psychotherapeutic settings; (2) to roll out the EBA approach in real-world psychotherapeutic settings to investigate (randomised controlled clinical trial) how it affects psychotherapy process and outcome; (3) to disseminate/notify the project study results to both academic and clinical communities. By combining sophisticated models of therapeutic process (Contextual and Quadripartite Models) with EBA, we expect to show increases in rapport, fewer ruptures and premature treatment