The MPFI-24P: A 24-Item Tool That Maps Psychological Flexibility and Inflexibility in Chronic Pain Patients
- Validation study (N=404 adults with chronic pain) of the MPFI-24P — a 24-item short form of the 60-item Multidimensional Psychological Flexibility Inventory, specifically adapted for chronic pain populations
- The instrument measures 12 facets: 6 flexibility processes (acceptance, present-moment awareness, self-as-context, defusion, values, committed action) and 6 corresponding inflexibility processes (experiential avoidance, lack of contact with present moment, self-as-content, fusion, lack of contact with values, inaction)
- The inflexibility scale was the stronger predictor of pain interference, depression, and work/social adjustment — inflexibility matters more clinically than flexibility for predicting dysfunction
- The 24-item short form performed comparably to the full 60-item MPFI in reliability and validity, making it practical for routine clinical use and session-by-session tracking
ACT for chronic pain has a measurement problem. Most clinicians assess outcomes (pain intensity, interference, depression) but not the process of change that ACT targets: psychological flexibility. Without process measurement, you cannot tell whether your intervention is working through the mechanisms it claims to work through — or whether improvement is simply due to non-specific factors like therapeutic alliance and expectancy.
The MPFI-24P, validated by Lavefjord and colleagues at Uppsala University in collaboration with Lance McCracken (one of the founders of ACT for chronic pain), addresses this gap with a practical instrument that takes under 5 minutes to complete.
What makes this tool clinically useful
The 24-item format is deliberately designed for repeated measurement. At 60 items, the original MPFI is too long for session-by-session administration. At 24 items, the MPFI-24P becomes feasible for routine outcome monitoring — a pre-session check-in that tells you which flexibility processes are shifting and which are stuck.
The 12-facet structure maps directly onto the ACT hexaflex model. Each of the six flexibility processes (acceptance, present-moment awareness, self-as-context, defusion, values, committed action) has a corresponding inflexibility counterpart. This is not just a total score — it is a process-level diagnostic that tells you where to focus in a given session.
The finding that inflexibility predicts outcomes better than flexibility is clinically important. It means that reducing experiential avoidance, cognitive fusion, and inaction may matter more than increasing acceptance and mindfulness — at least for pain interference and depression. This has direct implications for treatment emphasis: spending session time on reducing avoidance and fusion may yield faster functional gains than building flexibility from scratch.
How to implement
In ACT-based pain management: Administer the MPFI-24P at intake (baseline flexibility profile), then every 2-4 sessions. Track which inflexibility facets are highest at intake and whether they decline with treatment. If experiential avoidance remains high while defusion improves, your patient may be intellectually understanding ACT concepts without behaviorally engaging.
In multidisciplinary pain clinics: The MPFI-24P provides a shared language between psychologists, physiotherapists, and physicians. A patient with high fusion and low committed action needs a different treatment plan than a patient with high experiential avoidance and intact values — even if their pain scores are identical.
In research: The 24-item form enables measurement-intensive designs (daily diary, ecological momentary assessment) that were impractical with the 60-item version.
The MPFI-24P gives ACT therapists what they have lacked: a 5-minute, 12-facet process measure that tracks which flexibility mechanisms are shifting and which are stuck — session by session, not just pre-post.
Cross-sectional validation only (N=404); no data yet on sensitivity to change within treatment. The sample was recruited online, which may over-represent digitally literate patients with milder pain presentations. Factor structure was confirmed but not compared across pain subtypes (musculoskeletal vs neuropathic vs fibromyalgia). The study was conducted in Sweden — cross-cultural validity of the short form needs further testing. No clinical cutoffs are yet established for interpreting scores.