Antipsychotic drugs(APDs) have been effective to alleviate psychotic symptoms of schizophrenia. However, some schizophrenic patients do not respond to APDs. In addition to psychotic symptoms of schizophrenia, negative symptoms, excitement, violence, agitation, depression, and disorganization are frequently noted in patients with schizophrenia. Though APDs are the first line drugs for these symptoms, other drugs than APDs to augment the effects of APDs are efficacious for the treatment of these symptoms. Such augmenting drugs include benzodiazepines, anticonvulsants, antidepressants, lithium, and electroconvulsive therapy. These augmentation strategies can boost the effects of APDs or decrease the requirements of APDs, and consequently decrease the chance of the occurrence of side effects of APDs. Augmenting strategies are revewed for each class of drugs or treatment modality.