Effects of fenfluramine on the behavior of autistic individuals.
Fenfluramine helped four autistic children a little in 1987, but larger trials in older clients failed and the drug is now banned.
01Research in Context
What this study did
Four children with autism took the drug fenfluramine every day. Doctors watched their behavior for weeks.
This was a case series. No control group. Just four kids.
What they found
The kids showed fewer odd behaviors. They paid attention longer. No one felt sleepy or slow.
The gains were small but steady across the four children.
How this fits with other research
Calamari et al. (1987) ran a larger test the same year. They gave fenfluramine to older autistic teens and adults in a state home. After nine months, behavior did not improve and side effects appeared.
The two papers seem to clash. Age may explain the split. Young kids did slightly better. Older clients did worse.
Modern reviews like Rodgers et al. (2021) and Van Gaasbeek et al. (2026) never mention fenfluramine. They focus on early ABA, not pills.
Why it matters
You will not use fenfluramine today. The FDA pulled it from the market years ago. Still, the study reminds you that age and setting can flip a drug’s result. When you read old drug claims, check who was tested and where. Then stick with today’s evidence-based choices like early intensive ABA.
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02At a glance
03Original abstract
The present report, part of a national, multicenter study to investigate the effects of fenfluramine on autistic behavior, describes findings on four autistic children ranging in age from 7 to 20 years. Additional performance and parental observation measures apart from those of the multicenter study are included. Results of this study which indicated no significant side effects, a reduction in some deviant behaviors and an improvement in activity level/attention span, provide support for earlier reports. The possibility that fenfluramine's apparently positive effects might be to simply reduce inappropriate behaviors via lethargy was examined and not supported.
Research in developmental disabilities, 1987 · doi:10.1016/0891-4222(87)90004-7