Contribution of the serotonergic system to developmental brain abnormalities in autism spectrum disorder.

This is a narrative review, not a systematic review, so the selection of studies may be biased. Much of the evidence comes from animal models or postmortem human brains, which cannot prove causality in living patients. The authors state there is a lack of sufficient research on the specific brainstem nuclei involved, meaning the mechanisms are largely theoretical. Autism heterogeneity means findings from one subgroup may not apply to another.

The paper is supported by the National Institutes of Health (NIH) and the International Society for Autism Research. No conflicts of interest are explicitly declared in the provided text.

Do not interpret this review as evidence that serotonin-targeting treatments work. The paper highlights that autism has many different biological subtypes and that the specific brain mechanisms remain poorly understood, which explains why these treatments often fail or have mixed results.