Hepatic disease and psychiatric illness: relationships and treatment.

A relationship between hepatic diseases and psychiatric symptoms has long been speculated. While liver detoxication makes the exogenous substances harmless for the body, there are occasions where the liver may convert a harmless substance into a more toxic substance. With such an important role, the liver protects all the organs of the body. When liver is malfunctioning, toxic metabolites injurious to the brain may be produced. As the brain receives a high blood supply, a large amount of metabolites reach this organ. Hence, the metabolic function of the liver keeps a delicate reciprocal relationship between the two organs. In addition, a number of psychiatric medications affect liver functions. Another perplexing clinical problem is the difficulty in treating psychiatric symptoms in patients with liver disease. For example, benzodiazepines which do not affect the liver function in physically healthy psychiatric patients, may induce hepatic coma in patients with liver disease. Benzodiazepine antagonists produce dramatic and temporary improvement in patients with hepatic coma. Clinically, many psychoactive drugs produce hepatic complications. The very same drugs which produce hepatic side effects are required for the treatment of psychiatric symptoms in patients with hepatic disorders. To appropriately handle these situations, a thorough knowledge of the side effects of these drugs is necessary.