The induction of dissociative states: A meta-analysis

Dissociative states—disruptions in awareness and perception—occur across many psychiatric disorders and can be experimentally induced. This meta-analysis of 123 studies (6,692 individuals) measured state dissociation using a standard scale. At baseline, the largest effects were in dissociative and complex subtypes of post-traumatic stress disorder (PTSD-DC). In controlled experiments, mirror-gazing and several drugs (especially ketamine and cannabis) produced dissociation levels as high as or higher than baseline PTSD-DC. Effect sizes varied widely but were not consistently linked to study methods. The findings confirm that dissociation can be reliably modeled in the lab, with implications for measuring side effects and predicting outcomes in drug-based treatments.

Study at a glance

Abstract

Abstract Objective Dissociative states, characterised by discontinuities in awareness and perception, occur in a diverse array of psychiatric disorders and contexts. Dissociative states have been experimentally modelled in the laboratory through various induction methods but relatively little is known about the efficacy and comparability of different experimental methods. Methods This meta-analysis quantified dissociative states, as indexed by a standardised instrument ( Clinician Administered Dissociative States Scale ), at baseline in varied diagnostic categories and in response to different experimental induction methods (psychological techniques and pharmacological agents) in both clinical and non-clinical samples. Primary outcomes were state dissociation effect sizes (Hedges’s g ) (PROSPERO registration CRD42022384886). Results 2,214 papers were screened, yielding 123 eligible articles and 155 effect sizes comprising 6,692 individuals. High levels of baseline state dissociation were observed in multiple diagnostic categories relative to controls, with the largest effects found in the dissociative and complex subtypes of post-traumatic stress disorder (PTSD-DC). In controlled experiments, induced state dissociation was most pronounced in response to mirror-gazing and multiple pharmacological agents with effects exceeding baseline state dissociation in PTSD-DC in ketamine and cannabis. The effect sizes were characterised by pronounced heterogeneity but were not reliably associated with methodological features of the original studies. Conclusions Elevated state dissociation is present in multiple diagnostic categories and comparable or higher levels can be reliably induced in controlled experiments using psychological techniques and pharmacological agents. These results demonstrate the efficacy of several methods for experimentally modelling dissociation and have implications for measuring adverse events and predicting outcomes in clinical interventions involving pharmacological agents.