This paper examined the concentrations of arginine vasopressin (AVP) and oxytocin (OXY) in the cerebrospinal fluid (CSF) of autistic children (n=36) compared to controls children without psychiatric disease who needed lumbar puncture for some medical reason (n=36). The authors hypothesized that if these neuropeptides are involved in autism development, differences in levels would be more apparent in CSF than in plasma.