Rapid eye movement (REM) sleep behaviour disorder; an easily missed diagnosis, a readily treatable condition.

Rapid eye movement sleep behaviour disorder (R.B.D.) is a relatively new diagnosis, first described in the mid-1980s.' These case reports describe two psychiatric outpatients who presented with typical features of the disorder and who had an effective response to treatment with clonazepam. In one instance the patient had undergone several medical evaluations, including a sleep EEG, but without a definite diagnosis being reached. Both patients were diagnosed on clinical grounds, and showed a positive response to clonazepam. In both cases they experienced recurrence of symptoms of R.B.D. after discontinuation or dose reduction and improved again after rechallenge with clonazepam. This paper highlights the need for clinicians to be alert to R.B.D., a condition which is responsive to clonazepam. CASE REPORTS Case 1: A retired manual worker, age 83, married with 2 adult children, who lives with his wife, was assessed by a consultant in old age psychiatry in March, 1999. He had a history of major depression, noted by his general practitioner to have begun in October 1998, which had become more marked, with social withdrawal and anhedonia. Although no formal rating scales were used, the patient reached criteria for a depressive disorder, without psychotic features (DSM-IV). He was also found to be suffering from slight cognitive impairment, marked by constructional dyspraxia, although his scoring was 29/30 on the Mini-mental state 3 and 12/12 on the I/O section of the Clifton Assessment Procedures for the Elderly.4 Medical history was significant for ischaemic heart disease, left ventricular hypertrophy, diverticular disease and prostatectomy with inguinal hernia repair in 1983. He had been commenced on citalopram 20mg daily by his general practitioner in February 1999. He was continued on citalopram 20mg daily and admitted to a psychiatric day hospital for treatment on 3/3/99. The citalopram dosage was progressively increased to 30mg daily by mid-March 1999, then to 40mg daily by 21/5/99 and finally to 60mg daily by 5/7/99. From about the middle of March 1999, the patient began to complain of disturbing nightmares, which were associated with complaints of his body "jumping" at night while asleep, and occasionally of finding himself on the floor with some associated bruising as a result. He was definite that these were new experiences and stated that the nightmares in particular were both unusual and frightening. These experiences did not appear to be temporally related to the initiation of citalopram. A CT scan of the head, showed mild …