<qa>  What is the cause of the atypical antipsychotics?The atypical antipsychotics, such as olanzapine, risperidone, quetiapine, and ziprasidone, are effective in treating both the positive and negative symptoms in schizophrenia Kelleher et al., 2002. However, atypical antipsychotics have been linked to several forms of morbidity, including obesity, hyperlipidemia, and type 2 diabetes mellitus DM Bergman and Ader, 2005; Jin et al., 2004; Melkersson and Dahl, 2004. Compared with the general population, life expectancy in schizophrenic patients is shorter by as much as 20, attributable to higher rates of suicide, accidental deaths, and natural causes such as cardiovascular disease and DM Harris and Barraclough, 1998. Several studies have suggested that these metabolic abnormalities may lead to a greater vulnerability to cardiovascular disease and thus may contribute to the excessive mortality among schizophrenic patients. 