Recent studies have attempted to measure several biomarkers to understand the complex interactions of the anatomic systems
that may be involved in autism spectrum disorder (ASD). In CNS, galanin takes part in a variety of pathological and physiological
processes. Prior research has indicated it is involved in several neuropsychiatric disorders and has a role in inhibiting
the neuronal firing and release of serotonin, norepinephrine, and acetylcholine. To date, serum galanin levels have not been
investigated in the context of ASD. This study aimed, therefore, to compare the serum galanin levels of children with ASD
and healthy controls and to reveal any association between galanin level and the severity of ASD, as well as other psychological
and demographic parameters. Serum galanin levels were measured by radioimmunoassay in 116 children with ASD
and 98 healthy children. We observed significantly increased serum concentrations of galanin in children with ASD relative
to healthy children. Moreover, children with severe ASD had significantly higher galanin levels than those with less severe
disease. We also confirmed significant positive correlations between galanin and psychiatric parameters in children with
ASD. For the first time, we suggest a possible correlation between serum galanin and the degree of ASD severity. Increased
galanin levels may play a role in the pathogenesis of ASD.