Hypnotic suggestibility in dissociative and related disorders: A meta-analysis

Abstract

Elevated responsiveness to verbal suggestions following a hypnotic induction is hypothesized to represent a predisposing factor for dissociative disorders (DDs) and germane conditions. However, the magnitude of this effect has not been estimated in these populations nor has the potential moderating influence of methodological limitations on effect size variability across studies. This study quantitatively assessed whether patients with DDs, trauma- and stressor-related disorders (TSDs), and functional neurological disorder (FND) display elevated hypnotic suggestibility. A systematic literature search identified 20 datasets. A random-effects meta-analysis revealed that patients displayed greater hypnotic suggestibility than controls, Hedges’s g=0.92 [0.66, 1.18]. Elevated hypnotic suggestibility was observed in all subgroups but was most pronounced in the DDs. Although there was some evidence for publication bias, a bias- corrected estimate of the group effect remained significant. Moderation analyses did not yield evidence for any link between effect sizes and methodological limitations. These results demonstrate that DDs and germane conditions are characterized by heightened hypnotic suggestibility and have implications for the mechanisms, risk factors, and treatment of dissociative psychopathology.