The classic and variant forms of Creutzfeldt-Jakob disease.

Transmissible spongiform encephalopathies (TSEs), also known as prion diseases, are a group of progressive neurodegenerative disorders that affect both animals and humans. These diseases take part of their name from a striking and common neuropathological feature: spongiform ("sponge-like") degeneration of the brain. As the name also implies, TSEs can literally be transmitted from one host to another much like any other infectious disease. In these situations, however, symptoms may take months or years to appear in the recipient host. Otherwise, TSEs either develop spontaneously or rarely arise through genetic mutation and therefore occur as familial disorders. Regardless of their origin, all TSEs progress over a period of months inevitably leading to the death of the affected individual. From a neuropsychiatric perspective, it is notable that the newly identified variant form of Creutzfeldt-Jakob disease (vCJD) typically occurs in younger adults causing prominent psychiatric and/or behavioral abnormalities as important early manifestations of disease. This has forced a heightened awareness of vCJD among mental health professionals throughout the United Kingdom where the disorder occurs. Relevant features of both the classic and variant forms of Creutzfeldt-Jakob disease (CJD) will be reviewed.