PAIN AND DEPRESSION IN PATIENTS WITH CANCER

Background, Although the existence of a relationship between depressio n and pain in patients with cancer has been known for many years, the influence of one upon the other is still poorly understood. It has bee n thought that depressed individuals complain of pain more because of their psychiatric illness. Evidence from two studies indicate that pai n may induce clinical depression. Methods. In the first study, the aut hors examined both current and lifetime psychiatric diagnoses among pa tients with cancer who had high and low pain symptoms to examine the s trength of the relationship between depression and cancer pain. The sa mple consisted of 72 women and 24 men, with 39 women and 9 men in the high pain group, and 33 women and 15 men in the low pain group. In the second study, 35 patients with metastatic carcinoma of the breast wer e examined for pain intensity and frequency and mood disturbance. Resu lts. The prevalence of depressive disorders of all types was found to be significantly higher in the high pain than in the low pain group ac ross measures, 33 versus 13% (chi-square [degrees of freedom = 1] = 5. 90, P < 0.05). Furthermore, there was a significantly higher history o f major depression in the low pain group than in the high pain group ( chi-square [degrees of freedom = 1] = 3.86, P < 0.05). Also, in compar ison with patients in the low pain group, patients in the high pain gr oup were significantly more anxious and emotionally distressed. In the second study, pain intensity correlated significantly with fatigue, v igor, and total mood disturbance, and pain frequency correlated signif icantly with fatigue, vigor, and depression. Conclusions. This study c onfirms the high concomitant occurrence of pain and psychiatric morbid ity and suggests that pain may play a causal role in producing depress ion.