Concurrent changes in psychological distress and pain thresholds following brief mindfulness: an exploratory...

Clinical trials of brief mindfulness interventions (BMIs) for chronic pain frequently report small average effect sizes, which may mask substantial heterogeneity in treatment responses. Rather than testing general efficacy, this exploratory study investigated whether a BMI is associated with concurrently coupled psychological and sensory improvements within individuals, potentially reflecting top-down nociceptive modulation.

Fifty female outpatients with chronic pain completed a 2-week BMI. Psychological distress [pain catastrophizing scale (PCS) and hospital anxiety and depression scale (HADS)] and objective sensory markers of central sensitization [pressure pain threshold (PPT)] were assessed pre- and post-intervention. To explore treatment response heterogeneity, multivariate analyses-including principal component analysis (PCA) and cluster analysis-were conducted using individual change scores.

At the group level, the BMI did not produce statistically significant pre-post changes. However, exploratory multivariate analyses revealed strong intra-individual coupling of responses. PCA extracted a single dimension, "simultaneous psychological and sensory improvement," suggesting that reductions in catastrophizing, anxiety, and depression co-varied concurrently with increases in PPT. Furthermore, cluster analysis identified a highly responsive subgroup ("high psychological improvement") that exhibited significant concurrent increases in PPT, potentially representing a distinct clinical phenotype.

The true impact of BMIs in chronic pain may lie not in uniform group-level efficacy, but in the concurrent coupling of psychological and sensory improvements within specific individuals. These findings challenge "one-size-fits-all" approaches, highlighting the critical need for mechanism-based patient stratification to advance precision pain care.