The model of psychological flexibility and inflexibility presented within an Acceptance and Commitment Therapy (ACT) framework is one that is multifaceted and complex. Until recent years, however, measurement of the construct of psychological flexibility has largely been conducted in a unidimensional manner across research and clinical contexts. The emergence of the Multidimensional Psychological Flexibility Inventory (MPFI; Rolffs et al., 2016) has remedied this situation by providing the first assessment of its kind to simultaneously capture each dimension of the full psychological flexibility model in a theoretically consistent manner. The current study intends to provide independent validation of the MPFI’s psychometric properties and to further solidify the measure’s utility in more comprehensively measuring ACT constructs for research and clinical contexts. The study will examine the MPFI’s convergence with related measures, its predictive validity with pertinent outcomes, and its utility in relation to the current standard of psychological flexibility measurement.

Psychological flexibility has been identified as an important construct within Relational Frame Theory and the examination of third-wave behavioral therapies. While psychological flexibility is defined within the context of relational responding, there is no research that directly assesses its relationship to measures of equivalence. The current study examined the relationship between PEAK Equivalence Pre-Assessment and scores of psychological inflexibility (via the AFQ-Y) in school-aged children with disabilities. Pearson correlations were utilized to examine the relationships between scores on PEAK and the AFQ-Y, as well as to examine the correlations among PEAK subtests. A large negative and statistically significant correlation (r =-.64, p < .05) was found between measures of psychological inflexibility and PEAK equivalence scores. Correlations among PEAK Equivalence Pre-Assessment subtests were line with previous research by Dixon, Belisle, & Stanley (in review), providing additional information for the relationship among measured components of equivalence. These findings have implications for guiding educational and therapeutic intervention, as well as provide additional evidence of the utility of the PEAK Equivalence Module.

Research surrounding psychological flexibility has begun to develop in recent decades. It has proven to be an important construct within the examination of third wave behavioral therapies and Relational Frame Theory. Though defined within the context of relational responding, there is little research directly assessing the relationship of psychological flexibility to measures of equivalence. The current study compared the scores of the PEAK Equivalence Pre-Assessment (to measure equivalence) and the scores from the AFQ-Y (to measure psychological inflexibility) to examine this relationship in school-aged children with ASD. The relationship between the total scores of the PEAK assessment and the scores of the AFQ-Y was examined by using a Pearson correlation. Results showed a statistically significant negative correlation (r = -.63, p<.05) between these measures. A Pearson correlation was then also used to examine the correlations among the PEAK subtests. As anticipated, the results showed a significant positive correlation among each of the components of equivalence providing additional information regarding the relationship among measured components of equivalence. These findings support recent research, and can help guide future educational and therapeutic interventions. Keywords: Autism (ASD), equivalence, PEAK, psychological flexibility

Psychological flexibility (PF), the core process of Acceptance and Commitment Therapy (ACT; a third-wave cognitive-behavioral therapy), is the ability to stay focused on the present moment and intentionally engage in value-driven behavior despite experiencing difficult thoughts or feelings. This multifaceted construct includes components that target processes occurring both internally (e.g., cognitive processes) and behaviorally (e.g., value-consistent actions). Psychological flexibility has been applied to studies of adjustment in non-clinical samples and may be beneficial for college students as individuals navigate novel developmental stressors. Despite evidence suggesting the benefits of PF for psychological distress, additional work is needed to examine the potential of PF to foster adaptive functioning. The current study builds on previous research by a) conceptualizing distinct internal and behavioral components of PF as promotive factors and b) emphasizing competence-focused outcomes. This research examined the influence of components of PF over the course of an academic semester. A sample of college students (N = 250) completed self-report measures online at the beginning (Time 1) and end (Time 2) of a college semester. Measures included components of PF, competence, and demographic and academic information. Structural equation modeling was used to examine associations between components of PF at Time 1 on competence at Time 2, while accounting for the influence of competence at Time 1. Findings suggested that within the social domain, value-consistent action at Time 1 was associated with increased social competence at Time 2. Additional results indicated that baseline competence accounted for associations between components of PF and Time 2 competence. Implications for the dissemination of ACT-informed efforts to promote positive adjustment among college students are reviewed, and future research directions are discussed.

Chapter 1: Objective: The systematic review aimed to review the literature on burnout and its relationship to depression within the acute in-patient mental health services: psychiatric units and specifically, secure forensic mental health services. Methods: The review process included a systematic search across five databases (Medline, PsychINFO, Cinahl Plus, EMBASE and SCOPUS). Eligible studies included a cross-sectional design, using validated measures on burnout and depression. Results: A strong relationship between depression and emotional exhaustion was found. The relationship between depression and two other burnout dimensions (personal accomplishment, depersonalisation) was weaker and better explained in the context of other predicting (anxiety) and mediating (transformational leadership) variables. While depression severity across the studies was mostly mild with average burnout, service-specific variations were observed. Chapter 2: Objective: The empirical study aimed to explore any direct relationships of subjectively perceived understanding, predictability, control (job demands) with burnout and job satisfaction, and direct/in-direct effects of social support, psychological mindedness and psychological inflexibility (external and internal resources) on these relationships. Methods: Data was collected among Scottish National Health Service (NHS) employees (n=198) working in secure mental health services; forensic (58.65%) or intellectual disability (41.35%). Data gathered from the final sample of 141 nursing staff was analysed using t-tests, bi-variate correlations, hierarchical regressions and a series of mediation, moderation and moderated-mediation analyses. Results: The empirical study revealed that individual burnout dimensions were predicted by different job demands. Social support appeared as predictor rather than a moderator of job satisfaction and emotional exhaustion while psychological inflexibility was a mediator for job demands and burnout. Overall Conclusions: Concluding remarks for both, systematic review and empirical study, identify the need for further research, especially within the forensic mental health speciality. Both highlight that direct and in-direct effects may be important in explaining burnout while the empirical study makes further suggestion with regards to likely individualised pathways and two important resources of social support and psychological flexibility.

Acceptance and Commitment Therapy (ACT) is designed to target psychological flexibility, broadly defined as engagement with personal values regardless of the presence of difficult private events. As engagement with valued behaviors is imperative to psychological flexibility, clarification of values is an essential skill for clients to learn. Practicing of skills in treatment has historically been a difficult hurdle for clinicians to implement between sessions for clients as well. The present study examined the utility of a novel values card sort activity, as well as the utility of a rubber band to act as a reminding agent for engagement with values. 112 undergraduate students were randomly assigned to one of three conditions: a values card sort condition, a values card sort condition with a rubber band given to the participant, and a control card sort condition. Each participant completed questionnaires assessing connection with values, lack of contact with values, negative affect, and quality of life at baseline and at a one-week follow-up. A series of ANCOVAs were conducted to determine if there were any group differences between the three conditions at follow-up, with baseline scores as a covariate. The analyses indicate no significant difference between the conditions at follow-up across any of the variables of interest. Endorsement of prior therapy experience suggested unique trends and differential reaction to the card sorting activity. These findings suggest the values card sort may not be an effective intervention for subclinical populations but may be a fruitful intervention for clinically-elevated individuals.

Problematic levels of eating disorder (ED) spectrum problems are becoming increasingly pervasive on college campuses, especially among female college students. Research suggests that ED cognitions and a lack of body image acceptance are linked to diminished psychological flexibility (PF), which is linked to ED and other negative health symptoms. Two hundred thirty-six undergraduates completed an online survey, and mediation analyses were conducted. PF fully mediated the relation between ED cognitions and non-specific psychiatric symptoms and partially mediated the link between ED cognitions and ED symptoms. PF also partially mediated the link between body image acceptance and non-specific psychiatric symptoms, but not the relation between body image acceptance and ED symptoms. Findings suggest that clinical symptoms and one’s coping style are both important factors to take into consideration in case conceptualization and treatment, and suggest that therapies such as ACT that target PF may be beneficial in treating ED spectrum problems.

Muscle disorders are chronic, progressive conditions, the majority of which are without disease modifying treatments. Quality of life (QoL) is reduced in these conditions, and alternative methods, such as psychological intervention, may offer ways to improve QoL. Previous work has suggested that aberrant illness perceptions may be influential targets for psychological interventions; however, emerging evidence suggests that psychological flexibility might offer another treatment target. This thesis first presents a longitudinal investigation of the role of these two variables, alongside disability level, in explaining life satisfaction and mood measured four months later. Participants were recruited from charities and online communities, with data collected via online questionnaires. Here, illness perceptions and psychological flexibility, but not disability level, were cross-sectionally associated with all dependent variables. In prospective analyses psychological flexibility accounted for greater variance in life satisfaction and anxiety; while illness perceptions explained more variance in depression. However, after controlling for variance in time one dependent variables, psychological flexibility alone was predictive of life satisfaction and anxiety at time two. Therefore, psychological flexibility represents a possible influential target for psychological intervention in muscle disorders. Acceptance and Commitment Therapy (ACT) is a psychological intervention specifically designed to improve psychological flexibility. Subsequently, the results of the empirical study imply that ACT is worthy of trial with muscle disorders. However, there has been no comprehensive review of the use of ACT in chronic disease or long-term conditions. Therefore, Chapter 2 presents a systematic review of ACT as applied to chronic disease/long-term conditions. The aims were to collate all ACT interventions with chronic disease/long-term conditions; evaluate their quality and comment on efficacy. Ovid MEDLINE, EMBASE and Psych Info were searched, with a further search of citing articles undertaken using Google Scholar. Studies with mental health or chronic pain populations were excluded. Study quality was then rated, with a proportion re-rated by a second researcher. Seventeen studies were included, of which: eight were randomised controlled trials (RCTs), three used pre-post designs, and seven were case studies. A broad range of applications were observed (e.g. improving quality of life and symptom control, reducing distress) across many diseases/conditions (e.g. HIV, cancer, epilepsy). However, study quality was generally low, and many interventions were of low intensity. The small number of RCTs per application and lower study quality emphasise that ACT is not yet a well-established intervention for chronic disease/long-term conditions. However, there was promising evidence for certain applications: the parenting of children with long-term conditions, seizure-control in epilepsy, psychological flexibility and possibly self-management/lifestyle. The studies comprising this thesis suggest that, whilst psychological flexibility appears influential in muscle disorders, high-quality research into ACT interventions for chronic disease/long-term conditions is generally lacking. Therefore one cannot confidently generalise from existing studies that ACT will improve outcomes in muscle disorders. Thus an evaluation of ACT in the context of muscle disorders is now required. This should adhere to the methodological suggestions provided in the systematic review.

Psychological flexibility (PF), the core process of Acceptance and Commitment Therapy (ACT; a third-wave cognitive-behavioral therapy), is the ability to stay focused on the present moment and intentionally engage in value-driven behavior despite experiencing difficult thoughts or feelings. This multifaceted construct includes components that target processes occurring both internally (e.g., cognitive processes) and behaviorally (e.g., value-consistent actions). Psychological flexibility has been applied to studies of adjustment in non-clinical samples and may be beneficial for college students as individuals navigate novel developmental stressors. Despite evidence suggesting the benefits of PF for psychological distress, additional work is needed to examine the potential of PF to foster adaptive functioning. The current study builds on previous research by a) conceptualizing distinct internal and behavioral components of PF as promotive factors and b) emphasizing competence-focused outcomes. This research examined the influence of components of PF over the course of an academic semester. A sample of college students (N = 250) completed self-report measures online at the beginning (Time 1) and end (Time 2) of a college semester. Measures included components of PF, competence, and demographic and academic information. Structural equation modeling was used to examine associations between components of PF at Time 1 on competence at Time 2, while accounting for the influence of competence at Time 1. Findings suggested that within the social domain, value-consistent action at Time 1 was associated with increased social competence at Time 2. Additional results indicated that baseline competence accounted for associations between components of PF and Time 2 competence. Implications for the dissemination of ACT-informed efforts to promote positive adjustment among college students are reviewed, and future research directions are discussed.

Previous findings on the relationship between self-esteem and psychological outcomes are inconsistent. Therefore it appears that self-esteem, while related to crucial variables, does not provide a clear, direct, and comprehensive prediction of psychological symptoms. Thus, it was hypothesized that the relationship between self-esteem and symptomatology would be moderated by broader measures of how one interacts with emotional and cognitive stimuli.The purpose of this study was to examine the influence of self-esteem, psychological flexibility, and cognitive flexibility on psychological symptomatology. A sample of 82 undergraduate students at the University of North Texas completed self-report questionnaires measuring low self-esteem, psychological flexibility, measured inversely as inflexibility, cognitive flexibility, and psychological symptoms. Results of the study suggest that self-esteem (?= -0.59, p < 0.001) and flexibility (both psychological (?= 0.36, p = 0.001) and cognitive (?= 0.21, p < 0.05) are significant predictors of psychological symptoms. In other words, self-esteem is positively correlated with psychological symptoms, while psychological and cognitive flexibility are negatively correlated with psychological symptoms. Neither form of flexibility moderated the relationship between self-esteem and psychological symptoms in this sample. The findings of the current study are discussed as well as suggestions for further research related to self-esteem, psychological and cognitive flexibility, and their impact on psychological outcomes.