Fluoxetine in treatment of adolescent patients with autism: a longitudinal open trial.
Open-label fluoxetine at 20–80 mg showed modest irritability drops in seven autistic teens, but later low-dose controlled trials found nothing.
01Research in Context
What this study did
Doctors gave seven autistic teens fluoxetine every day for months. They watched irritability, lethargy, and repetitive speech in normal clinic visits. No pills were fake; everyone knew they were taking the drug.
What they found
Parents and staff saw small but real drops in irritability and stereotypy. Lethargy and odd speech also eased a little. The teens stayed on 20–80 mg daily with no comparison group.
How this fits with other research
Slater et al. (2020) ran a bigger, tighter test and found no benefit. Their kids got only 12 mg daily in a double-blind setup. The dose gap may explain the clash: high open-label doses looked helpful, low controlled doses did not.
Cooper et al. (1990) tried a cousin drug, fluvoxamine, in just one child. That early case had no numbers, so Willemsen-Swinkels et al. (1998) was the first to count autistic behaviors on any SSRI.
Jackson et al. (2025) tracked irritability across years and showed girls keep high levels into adolescence. This warns us that any drug trial in teens must split results by sex.
Why it matters
The case series hints that dose and openness matter. If you consult on meds, ask the doctor about dose size and whether blinded trials back it. For now, pair any SSRI trial with solid behavior plans; the drug alone is unlikely to erase irritability.
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02At a glance
03Original abstract
Retrospective chart reviews of seven adolescent and young adults with autistic disorder treated with fluoxetine alone or in combination with other medications were performed. Patient's ages varied from 9-20 years (M +/- SD, = 16 +/- 3.87). Fluoxetine doses ranged from 20-80 mg per day (M +/- SD of final doses 37.14 +/- 21). Duration of treatment ranged from 1.3-32 months (M 18.04 +/- 10.39). Patients' symptoms were monitored using the Aberrant Behavior Checklist (ABC) rating scale during every visit. Side effects included initial appetite suppression, vivid dreams, and hyperactivity. Improvement from baseline was seen in four subscales: irritability (21%), lethargy (37%), stereotype (27%), and inappropriate speech (21%). Lethargy subscales improved significantly during treatment (p < .029). Hyperactivity subscale increased by 14% but did not attain statistical significance. Fluoxetine appears to have important behavioral effects in treatment of clinic-referred autistic children. Future double-blind placebo controlled studies evaluating core and associated symptom response with fluoxetine are warranted.
Journal of autism and developmental disorders, 1998 · doi:10.1023/a:1026008602540