Predictors and Process Moderators of EMDR Therapy for Depressive Symptoms

The goal of this clinical trial is to evaluate which factors influence the effectiveness of Eye Movement Desensitization and Reprocessing (EMDR) therapy for depressive symptoms in real-world settings in Italy. The main questions the study seeks to answer are: * Which key factors influence EMDR outcomes in terms of mediators, moderators, and predictors of its effectiveness for depressive symptoms? * Do lower levels of individual psychological functioning at baseline, including high co-occurrence of personality domains and pathogenic personal beliefs, predict the effects of EMDR in treating depressive symptoms? * Are baseline psychological comorbidities (anxiety, dissociation, post-traumatic symptoms, emotional dysregulation, and sleep difficulties) and the quality of the therapeutic alliance related to the effectiveness of EMDR therapy for depressive symptoms? Participants will be both therapists and patients. * Eligible therapists must be certified members of the EMDR Italian National Association to ensure adherence to established standards in the practice of EMDR therapy and consistency in therapeutic delivery. Therapists will identify patients from their routine clinical practice who meet the study inclusion criteria and facilitate their enrollment. * Eligible patients must meet the following criteria: 1. Being 18 years of age or older. 2. being able to give informed consent. 3. presenting clinically significant symptoms in at least one of the following domains: anxiety, depression, dissociative, or post-traumatic stress symptoms. Individuals presenting with severe neurological impairment or other severe psychiatric conditions were excluded. Researchers will combine data from multiple N-of-1 trials (N-of-1 or single-subject clinical trials studies) using a Bayesian multilevel random-effects meta-analysis and meta-regression to generate robust estimates of treatment efficacy.