Cancer patients (N = 238) receiving palliative radiation treatment were followed for 8 months; 70 patients had died by the 8-month follow-up. Controlling for site of cancer and level of symptomatology at baseline, the authors studied the independent effects on mortality of pessimism, optimism, and depression. The findings show that the endorsement of a pessimistic life orientation is an important risk factor for mortality, but only among younger patients (ages 30-59). Attempts to replicate this finding with conceptually related constructs such as depression or optimism did not yield significant associations for either younger or older patients, suggesting that negative expectations about the future may contribute to mortality in unique ways. The authors conclude that attempts to link psychosocial factors to mortality should focus on specific psychological constructs instead of diffuse, global measures that cover many psychological phenomena and that the role of psychological processes in mortality may vary dramatically depending on age.