Examining the effects of process-based therapy: A multiple baseline study

Process-based therapy (PBT) is a model of psychological assessment and treatment focused on processes of change within particular people in their unique context. Many theoretical articles have been published on PBT, but few empirical studies explicitly examining PBT exist. The current study aimed to examine the effects of PBT using a multiple baseline design (N = 5) with intensive longitudinal assessment from baseline to 6-month followup. Overall, idiographic outcomes improved over time, with effects varying by participant. Gains appeared to be maintained at 6-month follow-up for two of three participants. In addition, individual-level networks contained fewer pathways overall or more inhibitory pathways over time, indicating that the relationships among symptoms changed over the course of treatment. At the same time, extent of change in standardized outcomes across participants varied and certain pathways in participant networks were consistent at multiple timepoints, suggesting that treatment was not universally effective across problem indices. The present study provides a proof of concept for PBT delivery and underscores the need to consider person-level outcomes when evaluating treatment efficacy. Future directions and limitations, including small sample size, are discussed.