alt Hacker NewsThe study that found a 47%* reduction (relative to symptoms at the start of the study) wasn't placebo controlled and had a sample size of just 18, so there's not even a control group to compare against.
> We note that due to the open-label nature of this initial trial, all of the assessments are subject to placebo effect, however the long-term improvements we observed here are promising.
Then, I suppose you could argue there's a possible, statistically significant, genetic component for efficacy of placebo, in autistic people. ;)