The differential efficacy of systemic therapy: a protocol for a systematic review and meta-analysis

Abstract Background: Systemic therapy is a widespread evidence-based psychotherapy approach. Its main goal revolves around the concept of viewing mental symptoms within the context of social systems (e.g., families, couples). Systematic reviews and meta-analyses have confirmed that systemic therapy significantly reduces symptom severity of DSM- or ICD-diagnosed patients. This meta-analysis aims to investigate the differential efficacy of systemic therapy, taking into account moderators (e.g., allegiance, adherence) and outcomes (system functioning) not considered in previous meta-analytical investigations.Methods: To conduct a comprehensive literature search, we will optimize search strategies from previous systematic reviews on systemic therapy. The search strategy presented in this protocol has improved the precision and sensitivity by using an iterative validation and optimization process. We will conduct the literature search in multiple electronic databases (PsycInfo, Pubmed, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL)). We will include all randomized controlled trials that report quantitative outcomes for symptom change and/or system functioning. For the calculations, we will conduct a Bayesian meta-analysis for the outcomes based on a random-effects model, a Bayesian meta-regression for the moderators, and Bayesian subgroup analysis for disorder-specific differences.Discussion: Understanding the differential efficacy of systemic therapy is essential for the conceptualization, performance, and analysis of future research and therapeutic practice. This meta-analysis faces potential limitations associated with the definition of systemic therapy, as well as methodological problems in systemic therapy research.