Antipsychotic medications form the mainstay of both the acute and maintenance treatment of schizophrenia. In recent years, atypical antipsychotics like risperidone, olanzapine and clozapine have come to be preferred because of their lower incidence of extra-pyramidal, anti-cholinergic and cardiac side-effects and a possible greater efficacy in reducing negative and neuro-cognitive symptoms (Ritchie et al., 2006).