Repetitive behavior disorders are prevalent among people with severe mental retardation. These disorders can interfere significantly with an individual's daily functions. This trial is part of a long-term project that has studied the biologic basis of and possible treatments for repetitive behavior disorders. The trial will evaluate the effectiveness of two medications, a selective serotonin reuptake inhibitor (SSRI) and an atypical antipsychotic, in treating repetitive behavior disorders in people with mental retardation.

Abnormal repetitive behaviors (odd or inappropriate movements, self-injury, and compulsions) are among the aberrant behaviors exhibited by individuals with mental retardation. However, little is known about their pathobiology and treatments are largely unconfirmed by controlled trials. For example, few controlled studies have examined the efficacy of pharmacological treatment of abnormal repetitive behavior in individuals with mental retardation.

This trial is part of a larger project designed to elucidate the neurobiological bases of repetitive behavior disorders and to develop rational, safe, and effective pharmacological treatments. Thus far, the project has established a pathophysiological basis for stereotyped behavior disorder, demonstrated the role of central dopamine deficiency in stereotyped behavior disorder, and provided evidence of the efficacy of both 5-HT uptake inhibitors and atypical antipsychotics in treating stereotyped behaviors.

There is currently little information to guide the clinician in deciding which drug class may be more effective for which abnormal repetitive behaviors and for which individuals. Moreover, little work has attempted to identify variables that may predict differential treatment response. This trial will assess the relative efficacy of an SSRI and an atypical antipsychotic across multiple categories of abnormal repetitive behaviors.

Inclusion Criteria

• Mental retardation
• Medically stable resident of either Western Carolina Center, Morganton, NC or Tacachale Community, Gainesville, FL
• Free of sensory deficits
• Ambulatory
• High rate of stereotyped behavior that may co-occur with self-injurious or compulsive behaviors

Exclusion Criteria

• Poor general health
• Cardiac, hepatic, or renal abnormalities
• Seizure within 4 months prior to study entry (patients on seizure medication who have not had a seizure within 4 months prior to study entry may participate)
• Tardive dyskinesia
• Akathisia
• Neuroleptic use within 6 months of study entry
• History of sensitivity to ergot alkaloids
• Hypertension