Date of Award


Level of Access Assigned by Author

Open-Access Dissertation

Degree Name

Doctor of Philosophy (PhD)




Sandra T. Sigmon

Second Committee Member

Jeffrey E. Hecker

Third Committee Member

Geoffrey L. Thorpe


Acceptance and Commitment Therapy (ACT), a multi-component intervention within the third-wave of behavioral therapy, has been shown to improve various outcomes in diverse populations and administration formats. This study utilized a dismantling design to investigate whether the values components of an ACT-based intervention for work stress add to the effects of the intervention beyond those of the mindfulness components and to explore possible mediators of change. Expanding beyond existing studies of ACT, a broad range of outcomes were examined pretreatment, post-treatment, and at three follow-up assessments in a small sample (N = 16) of employees of a university in the Northeast. Various factors proposed to possibly mediate changes in outcomes for each version of the intervention, in addition to various therapy process measures, were examined. Due to the small sample size, findings are preliminary. Results indicated that participants who received the complete intervention (ACT) experienced meaningful changes in a greater number of outcomes and process variables than did participants in the abbreviated group that omitted the values components (AT). Both groups experienced improvements on measures of stress, mental health, quality of life, affect and cognition. However, participants in ACT experienced less functional interference in work and social activities from distress, experienced improvements in work locus of control, trait anxiety, mindfulness, and coping behavior. Although AT appeared to be more effective for reducing job stress, participants in ACT experienced greater improvement in life stressor impact. Findings generally supported greater improvement in follow-up outcome scores for participants in the AT group and maintenance of post-treatment gains for participants in the ACT group. Although neither group reported meaningful changes in psychological flexibility, both groups reported changes in frequency of and belief in negative automatic thoughts and only participants in ACT experienced improvement on a measure of mindfulness. Correlational analyses suggested that different process variables were associated with different outcomes in the two groups. The possible roles values clarification may play in encouraging goal setting, motivation, and follow-through and the relation of these roles to the differential findings between groups, along with possible mechanisms of action in each group are discussed.