Aripiprazole (commercial name abilify) is the first commercially available drug with dopamine partial agonist effects approved for the treatment of schizophrenia and bipolar disorder since 2002 in the U.S. It reduces negative symptoms of schizophrenia efficiently and has a markedly lower incidence of extrapyramidal symptoms and tardive dyskinesia. However, the process of switching other antipsychotic agents to aripiprazole can result in a re-emergence or worsening of psychosis, along with unpleasant side effects such as insomnia, nausea, vomiting, anxiety and agitation. On the basis of a prior study demonstrating the efficacy and safety of aripiprazole in Taiwan population, we hence propose to apply a combined use of pharmacogenomics and therapeutic drug monitoring in the evaluation of the strategies of switching stable schizophrenia patients to aripiprazole from other antipsychotic agents.