Hepatic encephalopathy: a neuropsychiatric disorder involving multiple neurotransmitter systems.

Evidence from both biochemical measurements and from noninvasive techniques continues to suggest that neurotransmission failure rather than primary energy failure is the major cause of hepatic encephalopathy. Major neurotransmitter systems in which abnormalities have been identified include the glutamatergic, monoaminergic and opioid systems. Further elucidation of these neurotransmitter changes could provide novel pharmacological approaches in the treatment of hepatic encephalopathy.