Cyclothymia or unstable mood disorder? A systematic treatment evaluation with valproic acid

Cyclic changes in behaviour and mood which do not meet the criteria for bip olar affective disorder have been reported in people with intellectual disa bility (ID) since the beginning of the twentieth century. The present study postulates a functional disturbance of unstable mood disorder in such case s of an episodic pattern of disturbed behaviour, mood and anxiety. Since sy mptoms of hypomania or major depression are not observed in these individua ls, the unstable mood disorder cannot be regarded as being part of the bipo lar spectrum, although it resembles cyclothymia in some aspects. In this pi lot study, 28 subjects with ID were treated with valproic acid in dosages l eading to a mean plasma concentration of 63 mg L-1. A marked and sustained improvement was achieved in 68% of subjects in terms of both behaviour stab ility, and a reduction of symptoms in the mood, anxiety and motor domains.