LOW-DOSE NALTREXONE EFFECTS ON PLASMA CHEMISTRIES AND CLINICAL SYMPTOMS IN AUTISM - A DOUBLE-BLIND, PLACEBO-CONTROLLED STUDY

The effect of month-long naltrexone (NTX) treatment at a daily oral do se of 0.5 mg/kg/day was contrasted with placebo (PLC) in a double-blin d study with conjoint clinical and biochemical evaluations of therapeu tic effects. Modest clinical benefits were achieved with both PLC and NTX, with marginally better overall results following NTX, and degree of improvement appeared to be related to plasma chemical profiles. Mas sively elevated levels of beta-endorphin were observed in all children with assays using C-terminal antibody but not with an N-terminal anti body assay. In addition, 70% of the children exhibited abnormally low levels of adrenocorticotropic hormone, and smaller subsets exhibited e levated norepinephrine (60%), arginine-vasopressin (50%), and serotoni n (20%). The best clinical responders exhibited the dearest normalizat ion of the elevated plasma chemistries, especially in C-terminal-beta- endorphin and serotonin. There was some evidence of therapeutic carry- over effects in both clinical and biochemical measures in those childr en who received NTX before PLC. The results suggest that NTX only bene fits a subgroup of autistic children, who may be identified by the pre sence of certain plasma abnormalities. These results suggest a possibl e linkage between abnormal plasma chemistries, especially those relate d to the pro-opiomelanocortin system, and autistic symptoms.