Unsuspected multiple personality disorder: an uncommon source of protracted resistance, interruption, and failure in psychoanalysis.

Multiple personality disorder (MPD) is being recognized with increasing frequency. A great imitator, it may be encountered among patients who appear to have a wide range of other diagnoses, and have been in treatment for years without the presence of MPD being discovered. Nine of 241 MPD patients interviewed by the author, 3.7%, had been accepted for psychoanalysis. In only one case had the diagnosis been appreciated by the analyst prior to his accepting the patient for analytic treatment. Four patients were profoundly resistant and or inaccessible to analysis for protracted periods. In one of these cases the diagnosis became clear and successful analysis was concluded, but three analyses ended unsuccessfully with the diagnosis still unknown. Two patients' analyses were interrupted due to abrupt regressive events initially perceived to indicate severe ego weakness incompatible with sustaining an analytic process, but later appreciated as signs of MPD. In three cases it appeared that the patients' being accepted for analysis triggered the emergence of the dissociative process, and either the patient or the analyst decided to pursue a different form of therapy. Unsuspected MPD appears to account for a small percentage of stalemates, failures, interruptions, and early flights from analysis.