Targeting the glutamate system in the treatment of autistic spectrum disorders

Double-blind, placebo-controlled trial of risperidone plus topiramate in children with autistic disorder

BACKGROUND

Autism is a complex neurodevelopmental disorder that forms part of a spectrum of related disorders referred to as Autism Spectrum Disorders. The present study assessed the effects of topiramate plus risperidone in the treatment of autistic disorder.

METHOD

Forty children between the ages of 4 and 12 years with a DSM IV clinical diagnosis of autism who were outpatients from a specialty clinic for children were recruited. The children presented with a chief complaint of severely disruptive symptoms related to autistic disorder. Patients were randomly allocated to topiramate+risperidone (Group A) or placebo+risperidone (Group B) for an 8-week, double-blind, placebo-controlled study. The dose of risperidone was titrated up to 2 mg/day for children between 10 and 40 kg and 3 mg/day for children weighting above 40 kg. The dose of topiramate was titrated up to 200 mg/day depending on weight (100 mg/day for <30 kg and 200 mg/day for >30 kg). Patients were assessed at baseline and after 2, 4, 6 and 8 weeks after starting medication. Measure of outcome was the Aberrant Behavior Checklist-Community (ABC-C) Rating Scale.

RESULTS

Difference between the two protocols was significant as the group that received topiramate had a greater reduction in ABC-C subscale scores for irritability, stereotypic behavior and hyperactivity/noncompliance.

CONCLUSION

The results suggest that the combination of topiramate with risperidone may be superior to risperidone monotherapy for children with autistic disorder. However the results need to be further confirmed by a larger randomized controlled trial.

Stem cell therapy for autism

Autism spectrum disorders (ASD) are a group of neurodevelopmental conditions whose incidence is reaching epidemic proportions, afflicting approximately 1 in 166 children. Autistic disorder, or autism is the most common form of ASD. Although several neurophysiological alterations have been associated with autism, immune abnormalities and neural hypoperfusion appear to be broadly consistent. These appear to be causative since correlation of altered inflammatory responses, and hypoperfusion with symptology is reported. Mesenchymal stem cells (MSC) are in late phases of clinical development for treatment of graft versus host disease and Crohn's Disease, two conditions of immune dysregulation. Cord blood CD34+ cells are known to be potent angiogenic stimulators, having demonstrated positive effects in not only peripheral ischemia, but also in models of cerebral ischemia. Additionally, anecdotal clinical cases have reported responses in autistic children receiving cord blood CD34+ cells. We propose the combined use of MSC and cord blood CD34+cells may be useful in the treatment of autism.