An abnormal circadian pattern of melatonin was found in a group of young adults with an extreme autism syndrome. Although not out of phase, the serum melatonin levels differed from normal in amplitude and mesor. Marginal changes in diurnal rhythms of serum TSH and possibly prolactin were also recorded. Subjects with seizures tended to have an abnormal pattern of melatonin correlated with EEG changes. In others, a parallel was evidenced between thyroid function and impairment in verbal communication. There appears to be a tendency for various types of neuroendocrinological abnormalities in autistics, and melatonin, as well as possibly TSH and perhaps prolactin, could serve as biochemical variables of the biological parameters of the disease.

Plasma cyclic AMP is a "second messenger" that may reflect levels of activity of important neurotransmitter receptors. Plasma cyclic AMP was measured in 18 patients with childhood autism, 7 patients with pervasive developmental disorder, and 12 age- and sex-matched healthy controls. Plasma cyclic AMP was significantly elevated by over 100% in both groups of patients with childhood-onset psychoses compared with controls. Plasma cyclic GMP, a nucleotide linked to different receptors, was not elevated, suggesting that the finding may be specific.

No abstract