Psychological Flexibility and coping in females with endometriosis: do both constructs measure the same?

The Acceptance and Action Questionnaire-II (AAQ-II) measures psychological inflexibility (PI). PI entails the dominance of private experiences over chosen values and contingencies in guiding action. PI has emerged as a compelling construct to explain psychological distress (PD). However, the in-cremental validity of the AAQ-II to explain PD above and beyond other related and well-established constructs, such as coping, is relatively unclear. This study explored whether AAQ-II scores significantly contributed to explain PD above and beyond coping in females with endometri-osis. A total of 298 females with endometriosis completed the AAQ-II, self-report measures of cop-ing and PD. Correlation coefficients were conducted to explore the relations of PI with coping. Hi-erarchical Regression Analyses were conducted to examine the unique contribution of AAQ-II scores to explain PD. Higher scores on the AAQ-II significantly correlated with greater levels of dysfunctional coping and with lower levels of problem- and emotion-focused coping. PI significant-ly contributed to explain PD, above and beyond measures of coping. Furthermore, while coping scores accounted for a low percentage of the variance in PD, PI explained a high percentage of the variance in PD. Findings from this study support the incremental validity, and hence the theoretical utility of PI to explain PD above and beyond coping.