Modular Intervention for Depression Study

This randomized controlled clinical trial evaluates an algorithm-based personalized modular psychotherapy designed for adults with major depressive disorder whose condition is complicated by long-standing emotional, interpersonal, and self-related difficulties associated with early life adversity or personality functioning problems. These individuals often have poorer outcomes with standard psychotherapeutic approaches offered in public mental health services. The experimental intervention consists of a modular psychotherapy approach. All participants in this group receive a core, evidence-based depression treatment. Additional short therapy modules are added based on each participant's baseline clinical profile following a module-assignment algorithm, targeting specific difficulties such as problems with emotion regulation, sensitivity to rejection and interpersonal threat, difficulties in social functioning, or disturbances in self-concept and self-worth. The number and type of modules are personalized for each participant, allowing the treatment to be tailored while remaining feasible within routine public mental health care. The comparison group receives usual individual psychotherapy, which reflects standard care provided in community mental health centers in Chile. These treatments are delivered weekly by trained clinicians and are not guided by the modular protocol. 150 adults aged 18 to 65 will be recruited from public mental health centers. Eligible participants have major depressive disorder along with evidence of personality-related dysfunction and/or moderate to severe early life trauma. Participants are randomly assigned in a 1:1 ratio to either modular psychotherapy or usual care. The primary outcomes of the study are clinically meaningful reduction in depressive symptoms and remission from depression following treatment. Secondary outcomes include changes in emotional regulation, interpersonal functioning, daily emotional and interpersonal experiences assessed through brief smartphone-based daily reports, quality of the therapeutic alliance, and satisfaction with treatment from both patients and therapists. The purpose of this pilot trial is to determine whether a personalized algorithm-based modular psychotherapy approach improves clinical and functional outcomes compared to usual psychotherapy for people with complex depression in the Chilean public health system, and to inform future implementation and scaling of personalized mental health interventions.