Serotonin dysfunction in autism spectrum disorder: A neurological perspective

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental condition characterized by impaired social interaction, communication difficulties, and repetitive behaviours. Emerging evidence suggests that serotonin (5-hydroxytryptamine, 5-HT) plays a pivotal role in ASD pathophysiology. Serotonin's widespread influence on neurodevelopmental processes, including neurogenesis, synaptogenesis, and neural circuit formation, underscores its significance in ASD research. Hyperserotonemia, a condition marked by elevated blood serotonin levels, has been identified as the first biomarker of ASD, affecting approximately 30% of individuals with the disorder. Genetic studies implicate serotonin transporter (SERT) gene variations, such as the Ala56 variant, in ASD-associated behaviouralabnormalities. Functional imaging and biochemical studies reveal disruptions in serotonin synthesis, receptor binding, and transporter activity in autistic individuals.