Washington, Aug 13 - Decreased craving for pleasure is a symptom of a major depressive disorder, suggests a new study.

The research contradicts the long-held notion that those suffering from depression lack the ability to enjoy rewards, rather than the desire to seek them.

'This initial study shows that decreased reward processing, which is a core symptom of depression, is specifically related to a reduced willingness to work for a reward,' said Michael Treadway, Vanderbilt University psychologist.

Decreased motivation to seek and experience pleasurable experiences, known as anhedonia, is a primary symptom of major depressive disorder.

Anhedonia is less responsive to many anti-depressants and often persists after other symptoms of depression subside.

However, understanding the different components of anhedonia - the desire to obtain something pleasurable versus experiencing pleasure - has been difficult for researchers to determine in humans.