In plain language
Chronic low back pain and depression very often occur together, and the combination is harder to treat than either condition alone. Psychological therapies like Acceptance and Commitment Therapy (ACT) and Behavioral Activation Therapy for Depression (BATD) are assumed to work through specific processes of change — such as reducing psychological inflexibility or increasing daily activity. But do those process-outcome relationships work the same way in every patient? This study tested that assumption directly.
Embedded within a randomized controlled trial comparing ACT, BATD, and treatment-as-usual, 82 patients with chronic low back pain plus depressive symptoms answered brief smartphone surveys (ecological momentary assessment) over a 70-day intervention period, rating their pain, depressed mood, activity level, and six facets of psychological inflexibility every day. The researchers then examined, patient by patient, how strongly each process was linked to changes in pain and mood.
The headline result is heterogeneity: 86% of process-outcome associations were significantly different across patients, and for depressed mood the assumption that one model fits everyone was violated in all 21 associations tested. These individual differences did not line up with treatment group, responder status, therapy completion, or depression diagnosis — they were genuinely personal. The authors conclude that processes of change are "properties of people in association with therapies, not uniform properties of treatments," making the case for personalizing psychological interventions to each patient's therapeutic needs using idiographic (person-specific) analysis.
Key findings
- At the group level, higher daily fusion, self-as-content, lack of contact with values, and inaction were associated with more depressed mood, while higher activity level was associated with less depressed mood, across all three trial arms.
- The ergodicity assumption (that one dynamic model applies to all patients) was violated in all 21 process-depressed mood associations and in 8 of 21 process-pain associations; overall, 71% of process-outcome relationships required idiographic analysis.
- Meta-analytic pooling of within-patient effects showed very high heterogeneity for depressed mood (I-squared 66% to 96%, all p < .001) in every arm.
- Across both outcomes, 36 of 42 process-outcome associations (86%) were significantly heterogeneous, and 71% exceeded conventional thresholds beyond which reporting group averages is discouraged.
- Individual differences in process-outcome links appeared independent of treatment group (ACT, BATD, TAU), responder status, therapy completion, and clinical depression diagnosis.
- The authors conclude that traditional group-level analyses can at best serve as starting points for an idionomic approach, supporting personalization of psychological interventions for chronic pain with depression.
How to cite
APA
Sanabria-Mazo, J. P., Giné-Vázquez, I., Cristobal-Narváez, P., Suso-Ribera, C., García-Palacios, A., McCracken, L. M., Hayes, S. C., Hofmann, S. G., Ciarrochi, J., & Luciano, J. V. (2025). Relationship between outcomes and processes in patients with chronic low back pain plus depressive symptoms: Idiographic analyses within a randomized controlled trial. Psychotherapy Research, 35(6), 1001–1016. https://doi.org/10.1080/10503307.2024.2382429
BibTeX
@article{sanabriamazo2025relationship,
author = {Sanabria-Mazo, Juan P. and Gin{\'e}-V{\'a}zquez, Iago and Cristobal-Narv{\'a}ez, Paula and Suso-Ribera, Carlos and Garc{\'i}a-Palacios, Azucena and McCracken, Lance M. and Hayes, Steven C. and Hofmann, Stefan G. and Ciarrochi, Joseph and Luciano, Juan V.},
title = {Relationship between outcomes and processes in patients with chronic low back pain plus depressive symptoms: Idiographic analyses within a randomized controlled trial},
journal = {Psychotherapy Research},
year = {2025},
volume = {35},
number = {6},
pages = {1001--1016},
doi = {10.1080/10503307.2024.2382429}
}
Related work
- All publications by Joseph Ciarrochi (searchable, with free PDFs)
- Process-Based Therapy & Idionomic Analysis
- The Process-Based Assessment Tool (free download)
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.