Chronic subdural haematoma is notorious for leading to mistakes in diagnosis (Reference LishmanLishman, 1978). Before the advent of computerised tomography, only a fourteenth of cases in mental hospital patients was diagnosed in life (Reference ColeCole, 1978). We report a case presenting with polydipsia.

An elderly man with chronic psychosis was admitted to a medical ward with a 2-week history of polydipsia and agitation. Liaison psychiatrists transferred him to an acute psychiatry ward as a case of psychogenic polydipsia. He was found to be manic with euphoria and flight of ideas. Occasionally he also complained of headaches, had dyspraxia and became incontinent. This prompted an MRI (magnetic resonance imaging) brain scan showing bilateral chronic subdural haematomas with modest mass effect. Conservative management was tried at first. However, a fresh bleed with onset of hemiparesis led to emergency evacuation with full recovery and resolution of polydipsia.

Psychogenic polydipsia is a common occurrence amongst psychiatric inpatients (Reference Dundas, Harris and NarasimhanDundas et al, 2007). As the underlying pathophysiology of this syndrome is unclear, comprehensive evaluation of such cases is warranted.