Assessing acceptance and commitment therapy for adolescent mental health: Single-case A-B design with high temporal density assessments

Using a single-case A-B design with high temporal density assessments, the present study examined the impact of a ten-session group-based acceptance and commitment therapy (ACT) intervention on adolescents’ distress, psychological inflexibility, cognitive fusion, generalized pliance, and perceived ply workability. Six participants aged 16 to 19 years were invited to (i) attend a weekly ACT group, (ii) submit ecological momentary assessments daily for 69-days, and (iii) complete standardized questionnaires pre- and post-intervention. Data were analyzed using Hussey’s (2019) R Package for Robust Visualization, Analysis, and Meta Analysis of A-B Designs. In terms of the ecological momentary assessments, avoidance and pliance ratings significantly decreased across time for most participants. Findings regarding perceived ply workability were less consistent (i.e., although ply workability ratings significantly decreased for three participants, the overall effect was not statistically significant). In terms of the standardized questionnaires, across participants, there were overall negligible changes in distress and pliance, while avoidance and fusion ratings decreased from pre- to post-intervention. Results are discussed with explicit reference to the need for future research that identifies the key mechanisms/processes of change underlying intervention effectiveness.