May 1977

Hyperserotonemia and Amine Metabolites in Autistic and Retarded Children

Author Affiliations

From the Department of Medicine (Dr Hanley), Veterans Administration Hospital, Lexington, Ky, and the Department of Psychiatry (Drs Stahl and Freedman), University of Chicago Pritzker School of Medicine.

Arch Gen Psychiatry. 1977;34(5):521-531. doi:10.1001/archpsyc.1977.01770170031002

• Mean whole blood serotonin (5-HT) levels were elevated in groups of autistic and severely retarded children. Eight of 27 (30%) individual autistic children, 13 of 25 (52%) severely retarded children, two of 23 (9%) mildly retarded children, and none of the control children had statistically significant blood 5HT levels elevations (hyperserotonemia). Hyperserotonemic autistic children excreted more urinary 5-HT, 5-hydroxyindoleacetic acid (5-HIAA), tryptamine, and vanillylmandelic acid than did mildly retarded children with normal blood 5-HT levels. Rates of depletion and repletion of blood 5-HT levels in these two groups following reserpine therapy were identical. Oral tryptophan administration doubled urinary 5-HIAA excretion in both groups and raised urinary 5-HT levels in hyperserotonemic autistic children, but lowered urinary 5-HT in mildly retarded, normal blood 5-HT children. No clear mechanism for hyperserotonemia was found; the rationale for further investigations is discussed.