The association between liver disease and mental disorders has been recognized since the time of Hippocrates. Galen, a Roman physician of the 2nd century, described neurologic and psychiatric symptoms resulting from brain diseases and from diseases of other organs, including the liver. Morgagni, the father of pathologic anatomy, described the relation between liver failure and mental disorder in the 18th century. In one of his case reports, Morgagni described an alcoholic man with a history of abdominal pain and delirium who died in coma. Autopsy showed liver cirrhosis, but the brain was grossly normal. Further studies of hepatic encephalopathy continued in the 19th century. The works in which the modern concepts of hepatic encephalopathy are based were published in the 1950s.

A liver that is working poorly may not be able to get rid of toxic substances like ammonia (which comes from the intestines), and it may allow these substances to go into the brain and cause confusion.

Besides confusion, toxins in the brain cause changes in your sleep, your mood, your concentration, and your memory. If it gets bad, these toxins can even cause a coma.

These changes are all symptoms of hepatic encephalopathy. If you have encephalopathy, you may have problems driving, writing, and performing other activities of daily living. Signs of encephalopathy are trembling and hand "flapping."

Encephalopathy may occur when you have an infection or when you have internal bleeding, and it may also occur if you are constipated, take too many water pills, or take tranquilizers or sleeping pills. Your doctor might prescribe a medication called lactulose. Lactulose is a laxative syrup that makes your bowels move more often (up to two or three times a day) and helps get rid of ammonia.

If you are not acting like yourself, if you are confused, or if you are very sleepy, you should be taken to the emergency room immediately. These symptoms could be a sign of a serious medical problem. You should not drive when you have these symptoms.