[Intermetamorphosis after subdural haematoma: a familiar face, different identity]

A 78-year-old female patient developed a delusion following drainage of a right-sided subdural haematoma: she believed that her husband was her deceased father. The clinical presentation was consistent with a misidentification syndrome. In such syndromes, there is a fixed belief that a person, place, or object has a different identity or meaning. In this case, the phenomenon concerned intermetamorphosis, a subtype of misidentification syndromes. In intermetamorphosis, an individual is perceived as having completely transformed into another person: the physical appearance remains unchanged, but the identity is experienced as different. Treatment with olanzapine resulted in complete remission without recurrence. This case highlights the importance of early recognition of misidentification syndromes within neuropsychiatric and geriatric practice. Based on previous publications in the Nederlands Tijdschrift voor Geneeskunde and the Tijdschrift voor Psychiatrie, we outline diagnostic approaches and treatment options for misidentification syndromes.