Medication treatment in subjects with autistic spectrum disorders.

Autism is a pervasive developmental disorder that is aetiologically and clinically heterogeneous. Twin and family genetic studies provide evidence for strong genetic components. An international consortium using an affected sib pair strategy has found a promising linkage to a region on chromosome 7. In 10-15 % of the cases autism is due to associated medical conditions that affect normal brain functioning. Post-mortem studies on small case series report cellular abnormalities in the limbic system and cerebellum. Between 10 and 20 % of subjects with autism have macrocephalia, which is in accordance with MRI findings of an increased total brain tissue volume and enlargement most prominent in the occipital and parietal lobes. The most robust and well-replicated neurobiological abnormality in autism is an elevation of whole blood serotonin found in over 30% of the patients. Pharmacological interventions with serotonin reuptake blockers or with atypical neuroleptics that block both dopamine (D2) and serotonin (5-HT2) receptors seem to offer clinical benefit and merit further study.