In this paper narcoleptic states refer to states of drowsiness or sleep that occur both within the patient and the psychotherapist during a psychoanalytic psychotherapy session. The meaning is explored of recurring narcolepsy in a female patient for a period of four and a half years during her psychotherapy. The concept of internal cohabitation, which is a development of Bion's concepts of psychotic and non-psychotic personalities, is used to understand the narcoleptic phenomena in both patient and therapist and to explain the changes that took place in the patient.