A number of explanations have been proposed to account for findings that rates of
depression are elevated in persons with chronic, non-malignant pain disorders (CNPDs); for
example, that CNPDs are variants of depression (eg 'masked depression'), that the stress of
living with CNPDs contribute to the onset of depression ('diathesis-stress'), or that the
correlation of CNPDs and depression is a methodological artifact of studying treatment-
seeking samples. These alternative hypotheses are tested for one specific CNPD, chronic …