Effects of L-5-hydroxytryptophan in autistic children

Area of Science:

• Neuroscience
• Developmental Psychology
• Pharmacology

Background:

• Autism Spectrum Disorder (ASD) is a complex neurodevelopmental condition with varied behavioral manifestations.
• Serotonin (5-HT) is a neurotransmitter implicated in various brain functions, including mood and behavior.
• Previous hypotheses suggested a potential role for serotonin deficits in the underlying mechanisms of autism.

Purpose of the Study:

• To evaluate the behavioral effects of L-5-Hydroxytryptophan (L-5-HTP), a serotonin precursor, in combination with carbidopa in children with autism.
• To test the hypothesis that a functional deficit in brain serotonin contributes to the autistic syndrome.

Main Methods:

• A double-blind, placebo-controlled study involving three autistic children.
• Administration of L-5-HTP with carbidopa versus placebo over a 20-week period.
• Behavioral changes were assessed using direct behavioral observation and parent rating scales.

Main Results:

• Two out of three children exhibited behavioral changes during the study.
• Observed behavioral changes were not clearly attributable to the L-5-HTP and carbidopa treatment.
• No consistent or significant behavioral improvements were linked to the drug intervention.

Conclusions:

• The study's findings do not support the hypothesis of a functional brain serotonin deficit underlying autism spectrum disorder.
• L-5-HTP in combination with carbidopa did not demonstrate efficacy in altering behavior in the studied autistic children.
• Further research is needed to explore the complex neurobiology of autism and potential therapeutic targets.