In plain language
Process-based therapy (PBT) is not another brand of therapy. It is a meta-theoretical approach to psychological assessment and intervention, rooted in evolutionary science, that focuses on the dynamic processes of change happening within a particular person in their unique context. This paper introduces a special issue of the Journal of Contextual Behavioral Science — grown out of a 2022 PBT Think Tank organized by Drs. Hofmann and Hayes — that asks whether PBT can serve as a common framework across very different schools of psychotherapy.
The introduction explains why such a framework is needed. Traditional group-based research assumes that variation between people can stand in for variation within a person over time — the “ergodicity problem.” Research shows averages often fail to describe individuals: assertiveness, for example, has no overall effect on loneliness, yet for some people more assertiveness goes with more loneliness and for others with less. Two meta-analyses show that personalized interventions improve treatment effectiveness. PBT responds with an idionomic approach, in which data on particular people are treated as primary, and with the extended evolutionary meta-model (EEMM), which organizes change in terms of variation, selection, and retention across six psychological dimensions (affect, cognition, attention, self, motivation, and overt behavior) plus sociocultural and biophysiological levels. Psychopathology is redefined not as a latent disease but as maladjustment to a specific context.
The special issue presents six articles showing how PBT can deepen case conceptualization and treatment planning within acceptance and commitment therapy, cognitive behavioral therapy, compassion-focused therapy, emotionally focused individual therapy, functional analytic psychotherapy, and existential therapies. A striking trend emerges: the shared metatheoretical structure of PBT paradoxically makes clinicians freer to borrow techniques from other traditions without losing their theoretical bearings — a step toward what the editors ambitiously call “The Unification of Psychotherapy.”
Key findings
- Presents PBT as a meta-theoretical approach rooted in evolutionary science — an approach to what evidence-based therapy means, not a competing therapy, so it cannot supplant existing therapies.
- Explains the ergodicity problem: group-level findings cannot be generalized to particular people unless unrealistic statistical assumptions (stationarity and identical dynamics across people) are met.
- Reviews evidence that averages often fail to describe individuals (e.g., assertiveness relates to more loneliness for some people and less for others) and that two meta-analyses show personalized interventions enhance treatment effectiveness.
- Describes the extended evolutionary meta-model (EEMM), organizing change via variation, selection, and retention across six psychological dimensions (affect, cognition, attention, self, motivation, overt behavior) plus sociocultural and biophysiological levels.
- Redefines psychopathology as maladjustment to a specific context rather than the manifestation of a latent disease.
- Introduces six articles integrating PBT with ACT, CBT, compassion-focused therapy, emotionally focused individual therapy, functional analytic psychotherapy, and existential therapies, showing that PBT’s common language enhances case conceptualization and flexible, cross-tradition practice.
How to cite
APA
Ong, C. W., Hofmann, S. G., Ciarrochi, J., Menzies, R. G., & Hayes, S. C. (2025). Introduction to the special issue on process-based therapy. Journal of Contextual Behavioral Science, 35, Article 100874. https://doi.org/10.1016/j.jcbs.2025.100874
BibTeX
@article{ong2025introduction,
title = {Introduction to the special issue on process-based therapy},
author = {Ong, Clarissa W. and Hofmann, Stefan G. and Ciarrochi, Joseph and Menzies, Ross G. and Hayes, Steven C.},
journal = {Journal of Contextual Behavioral Science},
year = {2025},
volume = {35},
pages = {100874},
doi = {10.1016/j.jcbs.2025.100874}
}
Related work
- All publications by Joseph Ciarrochi (searchable, with free PDFs)
- Process-Based Therapy & Idionomic Analysis
Author: Joseph Ciarrochi (ORCID 0000-0003-0471-8100). Free copy hosted with permission for scholarly use. Please cite the published version via the DOI above.