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.