Sediel (generic name: tandospirone citrate, marketed as Sediel in Japan) is a new type of antianxiety drug developed independently by Sumitomo Pharmaceuticals. It acts selectively on only the serotonin nerves in the brain that play an important part in the formation of anxiety and depression, and demonstrates antianxiety and anti-depression effects. Since it does not act on the other nerves that are so extensive in the brain, there is virtually no hypnotic or sedative effect, and the drug displays virtually no drug-dependence or side effects such as drowsiness and dizziness. Sediel has been on sale in Japan since December 1996, and is recognized for recognized as effective in the treatment of generalized anxiety disorders. Tandospirone acts as a potent and selective 5-HT1A receptor partial agonist. It was also investigated the usefulness of 5-HT1A agonists for enhancing some types of cognitive performance and possibly social and work function in patients with schizophrenia, and related to this was discovered, that tandospirone in combination with atypical antipsychotic drugs can improve cognitive function in Schizophrenia.