Individuals carrying the T/T or T/C genotype of the T102C polymorphism of the HTR2A gene were responsive to the protective aspects of nurturing mothering, so that in the presence of high maternal nurturance, they expressed low levels of depressive symptoms, while this was not true with the carriers of the C/C genotype.
There was a significant gene-environment interaction, such that the urban residency was associated with low depressive symptoms in individuals carrying the T/T or T/C genotype of the T102C polymorphism, but not in those carrying the C/C genotype.
This study suggests a mechanism for the generation of different neuropsychiatric symptoms in AD from a single nucleotide polymorphism with reduced receptor binding in T102C 5-HT2A receptor gene homozygotes correlating with susceptibility to depressive symptoms, whereas the relative preservation of receptor binding in heterozygotes with AD correlating with susceptibility to hallucinations.