DRD2 and Cognitive impairment: The theory of atypicality, especially popular in the late 1990s, postulates that antipsychotics with higher affinity to the 5HT2 than to the dopamine D2 receptors (the atypical antipsychotics, or SGAs) were more effective in treating positive and negative symptoms and cognitive deficits and less prone to cause extrapyramidal side-effects compared with the FGAs, potent dopamine D2 blockers with low or negligible 5HT2 receptor inhibition (Meltzer and Massey, 2011).