Quetiapine is a second-generation antipsychotic (SGA) developed and subsequently marketed by AstraZeneca. In preclinical trials, quetiapine showed both the features associated with antipsychotic efficacy and a low rate of motor effects (Goldstein 1999; Nemeroff et al. 2002). The Phase III placebo-controlled clinical trials necessary for product registration confirmed this preclinical impression and demonstrated that quetiapine was efficacious in treating the manifestations of psychosis (Arvanitis and Miller 1997; Small et al. 1997). Of note, these studies also reported a low rate of treatment-emergent extrapyramidal side effects (EPS) with quetiapine use across a wide range of dosages that was comparable to the rate among placebo recipients. Quetiapine was approved in 1997 by the U.S. Food and Drug Administration (FDA) for the treatment of schizophrenia. Approval for use in Europe and in other countries worldwide has followed. Further clinical trials in patients with mania (McIntyre et al. 2005; Vieta et al. 2005) and patients with bipolar depression (Calabrese et al. 2005; Thase et al. 2006) led the FDA to approve additional indications for quetiapine's use in the acute and maintenance treatment of bipolar disorder. Most recently, the FDA has also approved a slow-release formulation of quetiapine for the treatment of schizophrenia (Kahn et al. 2007; Möller et al. 2007; Peuskens et al. 2007). Quetiapine is an established antipsychotic with broad efficacy and good tolerability, particularly with respect to EPS (Miodownik and Lerner 2006).