Exploring methodological approaches used in network meta-analysis of psychological interventions: A scoping review

Psychological interventions are complex in nature and have been shown to benefit various clinical outcomes. Gaining insight into current practices would help identify specific aspects that need improvement to enhance the quality of network meta-analysis (NMA) in this field. This scoping review aimed to explore methodological approaches in the NMA of psychological interventions. We searched PubMed, EMBASE, and Cochrane CENTRAL in September 2023. We included NMAs of psychological interventions of randomized controlled trials that reported clinical outcomes. Three independent researchers assessed the eligibility and extracted relevant data. The findings were presented using descriptive statistics. Of the 1827 articles identified, 187 studies were included. Prior protocol registration was reported in 130 studies (69.5%). Forty-six studies (24.6%) attempted to search for gray literature. Ninety-four studies (50.3%) explicitly assessed transitivity. Nearly three-quarters (143 studies, 76.5%) classified treatment nodes by the type of psychological intervention, while 13 studies (7.0%) did so by lumping different intervention types into more broader intervention classes. Seven studies (3.7%) examined active components of the intervention using component NMA. Only three studies (1.6%) classified interventions based on factors affecting intervention practices, specifically intensity, provider, and delivery platform. Meanwhile, 29 studies (15.5%) explored the influential effects of these factors using meta-regression, subgroup analysis, or sensitivity analysis. The certainty of evidence was assessed in 80 studies (42.8%). The methodological approach in NMAs of psychological interventions should be improved, specifically in classifying psychological interventions into treatment nodes, exploring the effects of intervention-related factors, and assessing the certainty of evidence.