Strategic Symptom Displacement in Therapy of a Motor Conversion Disorder Comorbid with PTSD: Case Presentation

There is no psychotherapy of choice for conversion disorders. We present a case of a motor conversion disorder comorbid with posttraumatic stress disorder, where we designed a psychotherapeutic approach based on the Bayesian model of brain functioning, specifically, the Bayesian model of functional neurologic symptoms. The model posits that such symptoms are produced as a result of hyper-precise prior beliefs (priors). Priors can be both conscious and unconscious and exist at different levels from perceptual to cognitive. Decreasing their precision/rigidity may then alleviate the related symptoms. In accord with this rationale, we used cognitive, experiential, and behavioral interventions meant to target and modify the putative priors. Central to this strategy was strategic symptom displacement. Application of this intervention coincided with reduction of the target motor symptom, indicating a possibility of causal relationship. We suggest strategic symptom displacement as an integral part of a universal therapeutic approach targeting priors: strategic modification of priors.