The Relationship Between Psychological Inflexibility and Well-Being in Adults: A Meta-Analysis of the Acceptance and Action Questionnaire

Psychological inflexibility is defined as the rigid responding to stimuli (e.g., unpleasant thoughts and feelings) that interferes with well-being and valued actions. It is the treatment target in acceptance and commitment therapy (ACT). Despite the centrality of the link between inflexibility and well-being to ACT theory, an empirical review clarifying the nature of this relationship has not been conducted. As such, the current meta-analysis examined the meta-correlation between psychological inflexibility, measured by the Acceptance and Action Questionnaire (AAQ) and its variants, and well-being. A systematic review yielded 151 studies, including 25 versions of the AAQ and 43 well-being measures. Consistent with ACT theory, higher psychological inflexibility was associated with worse well-being (r = −.47, 95% CI[−.49, −.45]). In addition, sample diagnosis, type of AAQ, and type of well-being measure significantly moderated this relationship. Overall, our findings support the hypothesized link between psychological inflexibility and worse well-being. Limitations include reliance on cross-sectional data, precluding causal interpretation.