Huntington's disease (HD) is an inherited
neurodegenerative disease that affects nerve cells in the brain leading to
mental decline and behavioral symptoms.
Visible signs and symptoms usually appear on people in their 30s or 40s.
Sometimes the onset of the disease begins early in life, even before the 20s. In
this case the condition is called juvenile Huntington's disease.
Depression is the most common psychiatric disorder associated with Huntington's
disease
There is a rating scale used to measure the progress of the disease. This rating
system is based on motor, behavioral, cognitive, and functional assessments.