Personality and colorectal cancer: the Fukuoka colorectal cancer study.

OBJECTIVE Although personality factors, especially emotional suppression and loss-hopelessness, have been linked to the occurrence and progression of cancer, little is reported specifically on colorectal cancer. It has also been claimed that a 'hysterical' personality characterized by exaggerated emotional expressions, egocentricity and ambivalent connection may be protective from cancer. This community-based case-control study examined whether personality factors relevant to emotional suppression or loss-hopelessness are associated with an increased risk of colorectal cancer, and whether factors related to the hysterical personality are associated with a decreased risk. METHODS The stress inventory (SI), a self-administered questionnaire to assess the possible disease-prone and other relevant personalities in Japanese, was completed by 497 patients with newly diagnosed colorectal cancer and 809 controls randomly selected in the Fukuoka area of Japan. RESULTS After controlling for age, sex and residence using a logistic regression model, none of the SI scales relevant to emotional suppression ('unfulfilled needs for acceptance', 'altruism', 'rationalizing conflicts/frustrations') or loss-hopelessness ('low sense of control', 'object-dependence/loss', 'object-dependence/happiness') was related to colorectal cancer. On the other hand, two scales representing elements of the hysterical personality, 'object-dependence/ambivalence' and 'egoism' were protectively associated with risk. Additional adjustment for body-mass index and lifestyle factors did not materially change these associations. CONCLUSIONS Although personalities relevant to the emotional suppression or loss-hopelessness may not be a risk factor for colorectal cancer in the Japanese population, ambivalent connection and egocentricity may be protective.