(PS10-C59) Psychological Flexibility as a Potential Mechanism of Change in Depression and Anxiety Symptoms over Time in a Community Sample of Adults Seeking Mental Health Treatment

Depression and anxiety are among the most prevalent and burdensome psychological disorders afflicting US adults, with lifetime rates of approximately 21% and 34%, respectively. Nearly half of people struggling with a depressive disorder report receiving treatment; however, only 20% report successful outcomes. Similarly, 30-60% of people receiving treatment for anxiety remain symptomatic after receiving psychotherapy. Psychological inflexibility, a transdiagnostic construct, refers to the rigid dominance of psychological reactions over chosen values to avoid experiencing unwanted internal distress. Even though depression and anxiety tend to co-occur over time, psychological flexibility (PF) may help explain their fluctuating relationships, leading to a potential treatment target. In the current study, we examined depression, anxiety, and PF at baseline and 4-week follow-up in a community sample of adults with elevated depressive symptoms enrolled in a larger intervention study (n = 55).

Participants interested in receiving self-help treatment were eligible if they had a current or lifetime diagnosis of major depressive disorder, at least current moderately severe depressive symptoms, and were not receiving specialty mental health treatment. Participants completed the Quick Inventory of Depressive Symptomatology-Clinician Version (QIDS), Patient Health Questionnaire (PHQ-9), State-Trait Anxiety Inventory (STAI), and Acceptance and Action Questionnaire (AAQ-II) at baseline and 4-week follow-up.

Bivariate correlations revealed significant associations between all measures at baseline and 4-week follow-up (ps < 0.05), such that symptoms scores were positively correlated with each other and negatively correlated with PF. Paired samples t-tests indicated that depression (PHQ t(45) = 7.95; QIDS t(47) = 9.89) and anxiety (t(35) = 2.76) symptoms both significantly improved over the 4-week interval (ps < .01). However, PF did not change over time (p = .42). Significant correlations were found when examining change scores for these measures, with strong associations between changes in depression and anxiety (PHQ r = 0.61, QIDS r = 0.71, ps = .001), and a moderate association between changes in PF and depression (PHQ r = -0.46, p < .01), but not anxiety (p = .12). Follow up exploratory analyses were conducted using hierarchical regressions. Results indicated that, when controlling for baseline anxiety, baseline PF was not a significant predictor of anxiety at 4-week follow up (R² change = .04, p = .16). Similarly, controlling for baseline depression, PF did not predict depression at week 4 (R² change = .07, p = .08). In other words, although PF appears to be related to symptom measures, it may not be as independent from symptoms as some research suggests.

Findings highlight the need to consider transdiagnostic processes in treatment development efforts, as co-occurring symptoms appear to change in tandem and may be related to PF or other emotion regulation mechanisms. As elevated mental health symptoms become increasingly identified and treated in primary care settings, understanding factors that influence the co-occurrence of depression and anxiety over time could improve treatment initiation, engagement, and maintenance.