“…11,12 Also, there has been growing literature reporting genetic association of the allele 7R with psychiatric traits/illnesses including novelty seeking, 13,14 attention-deficit hyperactivity disorder (ADHD) 15,16 as well as schizophrenia. 13,17 -31 Some studies declared association of the VNTR size polymorphisms with schizophrenia, 13,17,21,22,24,27 although not all studies agree. 18,23,25,26,28,30 -33 Also, supporting the functional role of the VNTR is evidence of selection favoring the allele 7R of the VNTR.…”