Among four studies that assessed the effect of treatment duration, two studies (one on preschoolers and the other included subjects with prior antipsychotic use) observed no significant effect [30, 35], the third reported increased risk for type 2 diabetes among adolescents [41] and the fourth study identified increased insulin resistance (without a significant increase in FBG) over a period of 96 months [42]. This evidence concerns the gene INS and type 2 diabetes mellitus.