*5.3. Autism Spectrum Disorder (ASD)*

The evidence for using ketamine to treat the core symptoms of ASD (i.e., broadly, impairments in social interaction and restrictive/repetitive behaviours) is preliminary. One randomised controlled pilot study used two doses of intranasal ketamine and saline placebo in a crossover design on a population of young people with ASD [83]. There were no specific effects of ketamine on the clinician- and self-reported measures of autism; the rates went down both after the placebo and ketamine. Notably, ketamine was welltolerated. However, a single case study found a dramatic reduction in the core symptoms of ASD for 36 h following a preoperative ketamine treatment [84]. Moreover, another single case study found improvements in depressive symptoms and the duration of eye fixation (an index of social skills) across 12 doses of intranasal ketamine in an individual with ASD and other psychiatric disorders [85]. Overall, the initial results were mixed, and further research is needed to ascertain whether ketamine is efficacious in addressing some of the core symptoms of ASD.
