Case Report: A possible association between significant dissociations after esketamine treatment and histrionic personality disorder.

Dissociation is a complex and transdiagnostic phenomenon defined as a disruption of, or discontinuity in, the normal, subjective integration of one or more aspects of psychological functioning. Dissociation has been identified as one of the most frequently occurring adverse effects associated with the use of esketamine nasal sprays. Individuals with high trait dissociation may be at a higher risk of experiencing an induced dissociative state and a significantly higher risk of experiencing severe induced dissociation. High esketamine-induced dissociation may act as a predictor of optimal therapeutic response, rather than solely an adverse effect. This case report describes an unusually intense and persistent dissociative reaction in a patient with histrionic personality disorder (HPD) undergoing esketamine therapy. The patient's marked dissociation upon treatment initiation raises the possibility that certain personality traits characteristic of HPD may heighten vulnerability to esketamine-induced dissociation. By explicitly examining a potential link between HPD and dissociation severity, this case highlights the importance of identifying patient-level factors that may amplify dissociative responses. Such knowledge has practical clinical implications for risk stratification, patient education regarding expected side effects, ensuring increased attention during the procedure.