Cortical serotonin 5-HT2A receptor binding and social communication in adults with Asperger's syndrome: an in vivo SPECT study.

<bold>Objective: </bold>The cause of autistic spectrum disorder (i.e., autism and Asperger's syndrome) is unknown. The serotonergic (5-HT) system may be especially implicated. However, cortical 5-HT2A receptor density in adults with the disorder has not been examined, to the authors' knowledge.<bold>Method: </bold>The authors investigated cortical 5-HT2A receptor binding in eight adults with Asperger's syndrome and in 10 healthy comparison subjects with single photon emission computed tomography and the selective 5-HT2A receptor ligand 123I iodinated 4-amino-N-[1-[3-(4-fluorophenoxy)propyl]-4-methyl-4-piperidinyl]-5-iodo-2-methoxybenzamide (123I-5-I-R91150).<bold>Results: </bold>People with Asperger's syndrome had a significant reduction in cortical 5-HT2A receptor binding in the total, anterior, and posterior cingulate; bilaterally in the frontal and superior temporal lobes; and in the left parietal lobe. Also, reduced receptor binding was significantly related to abnormal social communication.<bold>Conclusions: </bold>The authors' findings suggest that adults with Asperger's syndrome have abnormalities in cortical 5-HT2A receptor density and that this deficit may underlie some clinical symptoms. [ABSTRACT FROM AUTHOR]