Olanzapine is one of the SGAs (second-generation antipsychotics) which have been used for the treatment of patients with schizophrenia and bipolar disorder in Japan. Olanzapine has various affinities for multiple receptors, including dopamine D2 receptor, serotonin 5-HT2A, 5-HT2C, 5-HT6 receptors, and adrenaline alpha1, histamine H1, muscarine M1-M5 receptors as well. Therefore, olanzapine is known as MARTA(multi-acting receptor targeted antipsychotics). Numerous studies have been conducted to compare the effectiveness of olanzapine between SGAs and FGAs (first-generation antipsychotics). According to the head-to-head meta-analysis and large-scale studies like CATIE and EUFEST, olanzapine seems to have not only higher efficacy but also less discontinuation comparing to other anti-psychotics.