Everyone experiences variations in mood -- transitory blues, disappointments, the normal grief that accompanies the loss of someone you love. But a severe or prolonged depression that interferes with the ability to function, feel pleasure, or maintain interest is not a mere case of the blues. It is an illness. Researchers have demonstrated that it results from biochemical imbalances in the brain.

Depression is one of the most common mental disorders affecting approximately 340 million people in the world. No one is immune from depression - it occurs in people of all social classes, all countries and all cultural settings.