Effectiveness of a transdiagnostic protocol for anxiety and depression in primary care: The PsicAP-CV Stepped Wedge Cluster Randomized Trial

Introduction: Anxiety and depressive disorders represent a public health challenge, with high prevalence rates and considerable impact on quality of life (QoL) and functioning. Despite evidence supporting the efficacy of transdiagnostic cognitive behavioural therapy (TD-CBT), its implementation in settings such as primary care (PC) remains limited. The aim of this paper is to analyse the results of the PsicAP-CV, a clinical trial evaluating the effectiveness and implementation of TD-CBT in the PC setting. Methods: The study included 320 patients from the PsicAP-CV trial, a Stepped Wedge Cluster-Randomised Trial (SW-CRT). Symptoms of anxiety and depression were assessed, as well as QoL and functioning. Linear models were used to study treatment effects on outcomes and rates of recovery, reliable recovery and deterioration were calculated. Results: findings indicate that TD-CBT is more effective than treatment-as-usual (TAU) in reducing symptoms of anxiety and depression, as well as improving QoL and functioning. In addition, although the overall reduction in symptomatology was similar between patients who received immediate treatment (EG1) and those who received delayed treatment (EG2), there was a trend in favour of the EG1 group in the recovery indicators. Discussion: these findings confirm the efficacy of TD-CBT for treating common mental disorders in PC and point to SW-CRT designs as a feasible and ethically sound avenue for implementing and scaling these evidence-based interventions within public health systems. They also support the broader integration of psychologists into PC, thus offering a scalable model that can significantly improve access to and outcomes of mental health care. Trial registration: EURADICT 2013-001955-11/ISRCTN58437086.