We report a rare and striking, but under-recognised, cause of reported sleep-talking to a specialist sleep clinic. A 67 year-old right-handed bus driver was referred with one year's history of sleep-talking reported by his bed-partner of eighteen months. The somniloquy occurred on most nights, beginning within ten minutes of sleep and lasting several minutes to hours. The speech was elaborate relating to ex-girlfriends, often describing explicit sexual activities.
Nocturnal polysomnography demonstrated clinically significant obstructive sleep apnoea and the working diagnosis was that obstructive events were triggering a non-REM parasomnia.
On review two months later his partner reported on-going nocturnal speech. However, the patient's mounting curiosity had led to the implementation of surreptitious night-time electronic recordings. It soon became apparent that his partner's account was fictitious. Full psychiatric evaluation of his partner excluded morbid jealousy and psychotic illness.
We highlight the psychological phenomenon of gas-lighting, coined from the 1938 play Gas Light, in which a husband systematically torments his unsuspecting wife in order to provoke admission to a mental health unit. This phenomenon should be considered amongst the differential diagnoses of unusual presentations to sleep clinic, especially pertinent in this setting as the clinical assessment relies heavily on the bed-partner account.