LONG-TERM ADMINISTRATION OF VALPROIC ACID IN THE TREATMENT OF AFFECTIVE SYMPTOMS IN PEOPLE WITH MENTAL-RETARDATION

We report the results of an open trial of valproic acid in the treatme nt of affective symptoms in people with mental retardation. The study population consisted of 209 people with mental retardation who were se rially referred to a tertiary-care medical center for evaluation of be havioral symptoms. Criteria for treatment included the presence of thr ee of the four following symptoms: irritability, sleep disturbance, ag gressive or self-injurious behavior, and behavioral cycling. Twenty-on e patients met enrollment criteria and were studied prospectively for a 2-year period. Two patients were lost to follow-up. One patient expe rienced severe drug side effects. Eighteen patients completed the stud y. Fourteen patients (78%) responded favorably to treatment and were m aintained on valproic acid for the 2 years of the study (p<0.001). Med ications prescribed at the time of enrollment were usually discontinue d, including neuroleptic medication in 9 of 10 patients and in all pat ients (N=3) who were receiving phenobarbital. A history of epilepsy or a suspicion of seizures was strongly associated with a favorable resp onse to valproic acid (p<0.005). The results of this study suggest tha t people with mental retardation and concurrent affective disorders ca n be recognized by a cluster of developmentally appropriate symptoms s uch as those listed above. In addition, affective symptoms can be succ essfully treated with valproate with reductions in neuroleptic and bar biturate anticonvulsant medication. Further study of the comparative b enefit of valproate and carbamazepine in this population is warranted.