Neurochemical Study of Dopamine Functioning in Autistic and Normal Subjects

Plasma prolactin (PRL) and homovanillic acid (HVA) levels, and urinary HVA and dopamine (DA) excretion, were measured in groups of unmedicated autistics, medicated autistics, and normal controls. No significant differences were found between unmedicated autistics and normal controls in plasma PRL and HVA levels. Excretion rates of urinary HVA and DA were also similar in the unmedicated autistic and normal subjects. Plasma PRL and HVA, as well as urinary HVA excretion, were significantly increased in the autistics on neuroleptic medication compared to the unmedicated autistics. A significant correlation (r=0.46, p =<0.05) was observed between dose of neuroleptics and plasma PRL values; the correlation (r=0.42) between neuroleptic dose and plasma HVA levels approached significance (p=0.06). In contrast, no differences were observed in urinary DA excretion between medicated and unmedicated autistics. In general, the findings indicate that peripheral indices of dopamine functioning are normal in autistic subject

Whole blood serotonin and tryptophan in autism: Temporal stability and the effects of medication

Whole blood serotonin (5-HT) was significantly increased in a drug-free autistic group (n=17) compared to age-and sex-matched normal control (n =20). Blood tryptophan (TRP) values and platelet counts were similar in unmedicated autistics and normal subjects; but whole blood concentrations of TRP were significantly lower, and 5-HT values tended to be lower in the medicated group compared to unmedicated autistics. Highly significant intraclass correlation coefficients and low mean percentage differences were found for repeated measures over a year's period of whole blood 5-HT and the platelet count in the unmedicated but not in the medicated group. Blood TRP values were highly variable over time in both the medicated and drug-free autistic group

Understanding emotional transfer in children with autism spectrum disorders

The present study examined the understanding of emotional transfer in 11 children with autism, 20 children with PDD-NOS and 31 typically developing children, aged 6 to 12 years. Children were asked about their emotional responses to successive, conflicting emotional situations. All children reported that preceding emotional situations would influence their emotional response towards a successive situation. Children from the typically developing group reported a stronger influence of preceding negative versus positive emotions. However, children with autism reported equal effects of preceding positive and negative emotions, and children with PDD-NOS were relatively unaffected by the preceding emotions. These findings may indicate a scripted understanding of emotions in children with autism in contrast to a more personalized understanding of typically developing children. © The Author(s), 2010