This Discovery documentary deals with a very rare and unusual prion disease called Fatal Familial Insomnia or FFI for short.

FFI is a prion disease that targets the thalamus, of which of its many functions is the sleep regulator of the body. The prions form aggregates of amyloid plaques that destroy the neurons in this area.

The age of onset is variable, ranging from 30 to 60, with an average of 50. However the disease tends to prominently occur in later years, primarily following childbirth.

Death usually occurs between 7 and 36 months from onset. The presentation of the disease varies considerably from person to person, even among patients from within the same family.

The disease has four stages, taking 7 to 18 months to run its course:

The patient suffers increasing insomnia, resulting in panic attacks, paranoia, and phobias. This stage lasts for about four months. Hallucinations and panic attacks become noticeable, continuing for about five months. Complete inability to sleep is followed by rapid loss of weight. This lasts for about three months. Dementia, during which the patient becomes unresponsive or mute over the course of six months. This is the final progression of the disease and the patient will subsequently die.

Other symptoms include profuse sweating, pinprick pupils, the sudden entrance into menopause for women and impotence for men, neck stiffness, and elevation of blood pressure and heart rate. Constipation is common as well.