Delusional misidentification syndromes (DMSs) involve the delusional misidentification of the physical and/or psychological identity of the self or others. DMSs always exist in association with a specific mental disorder.The treatment of DMSs usually follows the treatment of the underlying mental disorder. From an aetiological standpoint. DMSs may be grouped as being associated with either a functional psychosis or a psychotic disorder secondary to a general medical condition. Additionally, associated mood psychopathology is not uncommon.The mainstay of treatment of DMSs involves antipsychotic medication, but various thymoleptics and electroconvulsive therapy (ECT) have an important role in treatment. Supportive psychological therapy can also be an important therapeutic adjunct.