A motivational theory of depression states that depression consists of low expectations and low values for rewards. This theory accurately describes one class of depression, the affective disorders. The present study tested its accuracy for another class of depression, adjustment disorder with depressed mood. This class of depression is precipitated by environmental stresses, such as chronic illness. The focus was therefore on people (N = 48) who were experiencing terminal cancer and nonterminal cancer. Results supported each prediction generated by the motivational theory. The cancer patients exhibited low expectations and low values; hence, they were unmotivated and depressed. Implications are that some of the symptoms exhibited by cancer patients may be manifestations of negative beliefs rather than physical impairments.
The present experiment tested the motivational theory of depression, which states that depression is low motivation for rewards. Reward motivation is defined as the multiplicative product of the person's expectancies for rewards times his or her values for those rewards.
The theory states that depressed people are relatively pessimistic and anhedonic toward rewards: They expect to obtain few rewards and they undervalue them; hence, they are undermotivated for rewards (