''Depression'' is more than a serious economic downturn. What distinguishes a depression from a harsh recession is paralyzing fear--fear of the unknown so great that it causes consumers, businesses, and investors to retreat and panic. They save up cash and desperately cut spending. They sell stocks and other assets. A shattering loss of confidence inspires behavior that overwhelms the normal self-correcting mechanisms that usually prevent a recession from becoming deep and prolonged: a depression.