A Pilot Trial of Sodium Benzoate, a D-Amino Acid Oxidase Inhibitor, Added on Augmentative and Alternative Communication Intervention for Non-Communicative Children with Autism Spectrum Disorders

Background: This open-label clinical trial examined the efficacy and safety of a d-amino oxidase inhibitor, sodium benzoate, in the treatment of non-communicative children with autism spectrum disorder. We hypothesized that benzoate, through indirect glutamate stimulation, may enhance learning in communication. Method: Six children (five boys, one girl, 3-year-7-month to 9-year-6-month of age) completed the 12 weeks of study of receiving sodium benzoate in conjunction with communication training program. The outcome measures were Receptive and Expressive Vocabulary Test-Chinese, parent-reported Adaptive Behavior Assessment System-II, number of core vocabularies learned in the applied communication learning system, Chinese child developmental inventory and parenting stress index. Safety assessments included biweekly recorded vital signs, body weight, body height and adverse events. Results: We noted improvement of communication in half of the children on benzoate. An activation effect was reported by caregivers in three of the six children, and was corroborated by clinician’s observation. Conclusion: Though the data are too preliminary to draw any definite conclusions about efficacy, they do suggest this therapy to be safe, and worthy of a double-blind placebo-controlled study with more children participated for clarification of its efficacy.