The effects of fenfluramine on communication skills in autistic children.

Doctors gave six boys with autism a daily pill called fenfluramine. They tracked the boys’ talking, pointing, and other communication for nine months. There was no comparison group—just the boys before and after the drug.

At the end of nine months, nothing had changed. The boys spoke no more words and used no more gestures than before. Fenfluramine simply did not help communication.

Sievert et al. (1988) tried the same drug two years later and also saw no reliable gains in social or language skills. Their result lines up with this study—fenfluramine is a dead end for autism communication.

Mancil et al. (2009) took a different path. Parents used milieu therapy plus functional communication training at home. Three young children quickly asked for toys and snacks with words or pictures. A pill failed; teaching worked.

Young (2020) pooled nine Korean FCT studies and found medium communication gains. Again, behavioral teaching beat the drug that did nothing.

You can stop wondering about an old diet pill for language goals. Focus your energy on parent-mediated FCT, milieu teaching, or other ABA-based communication programs. These methods give you data you can see and parents can use at home.