Based on present knowledge, in this work we review the importance of the pharmacogenetic tests in the treatment with antipsychotic drugs. Many associations have been reported between different genetic markers and response to treatment as well as to the appearance of adverse reactions. However, up to now, no "prime" biomarker capable of unequivocally predicting the clinical benefits of a specific treatment or its toxicity has been identified. The use of individual pharmacogenetic markers has been demonstrated to have little clinical utility, and therefore the combination of information obtained from the analysis of different genes seems to be a more promising strategy. Inclusion of pharmacogenetic tests in clinical trials conducted prospectively and that include a large number of cases could, undoubtedly, significantly contribute to the development of individualized medicine protocols.