Placebo effects and participant heterogeneity in clinical trials of autism spectrum disorder

In The Lancet Psychiatry, Suma Jacob and colleagues report the largest randomised controlled trial so far published of pharmacological treatment for autistic adults.1 This phase 3 multicentre trial (V1aduct) tested the efficacy and safety of balovaptan, a selective brain-penetrant receptor antagonist of the vasopressin 1a (V1a) receptor, on social adaptive behaviour, as measured by the Vineland-II two-domain composite (2DC) score, a composite of the Vineland-II socialisation and communication domains.