An Examination of the Validity of the Differentiation-of-Self Hypothesis and Its Mechanism Related to Negative Life Event Aversion among Japanese University Students

This study examined the validity of the differentiation-of-self hypothesis for Japanese university students, and its mechanism in relation to negative life event aversion. Although the differentiation-of-self hypothesis is accepted as one of the basic hypotheses in the clinical field of family therapy in Japan, empirical studies on the subject are scarce. Further, there are few studies, internationally, on its mechanism. A questionnaire survey was conducted with university students (n = 250) to measure their differentiation of self, maladaptive states, and negative life event aversion. Compared to the better-differentiated group, the less-differentiated group had higher scores both for maladaptive states—somatic symptoms (t(223) = -2.70, p = 0.008), social dysfunction (t(211.00) = -3.30, p = 0.001), and severe depression (t(208.78) = -4.08, p < 0.001)—and negative life event aversion—interpersonal domain (t(223) = -3.96, p < 0.001) and achievement domain (t(223) = -3.83, p < 0.001). The results supported the validity of the differentiation-of-self hypothesis for Japanese university students, and that cognitive tendencies toward negative life events may be part of the mechanism for less-differentiated individuals’ subsequent vulnerability. This suggests the effectiveness of cognitive interventions.