Association of serotonin concentration to behavior and IQ in autistic children.

Twenty-five boys meeting DSM-III criteria for infantile autism were evaluated for IQ, age, and behavior score on the Autism Behavior Checklist (ABC), in order to determine the ability to predic platelet-rich plasma (PRP) serotonin concentrations. Multiple regression techniques were used to adjust the PRP serotonin concentration for medication and whole blood platelet count to allow meaningful comparisons of serotonin concentrations among the autistic children. Though we found no significant correlation between the adjusted serotonin concentration and the IQ, or between the adjusted serotonin concentration and the various ABC scale scores, four individual items of the ABC did correlate with the adjusted serotonin concentration. Individuals with all of these items appear to be more severely affected with the disorder of autism and have a tendency to higher adjusted PRP serotonin concentration.