One of the main concerns regarding the care of patients with mental retardation is the management of behavioral disturbances.

This paper reports the results of a study in which an atypical antipsychotic (Quetiapine or Risperidone) was added to Valproate in the treatment of severe aggressive behavior in patients with mental retardation.

We followed 31 patients with mental retardation who, upon admission, presented with irritability and/or aggression, for a period of 6 months in order to assess the evolution of behavioral disturbances and the presence of treatment side-effects.

This is a naturalistic, prospective study. the inclusion criteria were the presence of mild, moderate or severe mental retardation associated with irritability and/or aggression. Two psychometric instruments were used - Overt Aggression Scale - Modified (OAS-M), the irritability and aggression subscales and Clinical Global Impression Scale (CGI). On the basis of severity of behavioral disturbances, two groups of patients were formed. Those with low scores were treated with Valproate and those with high scores were treated with both Valproate and an atypical antipsychotic (either Quetiapine or Risperidone).

Valproate monotherapy is an effective treatment for low intensity irritability and aggression. the association of Quetiapine or Risperidone with Valproate led to a marked improvement of severe aggression. This improvement was maintained for the duration of the study. Quetiapine determined a faster improvement of symptoms than Risperidone did.

Associating Quetiapine or Risperidone with Valproate is an effective and well tolerated means of controlling marked aggression in patients with mental retardation.