Contextual Behavioral Science (CBS) and Acceptance and Commitment Therapy or Training (“ACT” in either case) are arguably entering their 5th decade of development. This paper describes features of their early history and divides development into three phases, plus a fourth that is just beginning. In the context of that review, it examines what can be learned by a content analysis of the first ∼1000 randomized controlled trials on ACT-based interventions, from 1986 through 2022. The expansive vision of CBS and the early ACT research base defined their breadth as far wider than psychological intervention targeting traditional psychiatric syndromes, emphasizing instead the principles, processes, and components needed for a more generally applicable approach. After an era of scientific establishment, ACT research has expanded globally and topically. Many RCTs now take place in lower- and middle-income countries with cultural and policy environments that give rise to unique research priorities. Finally, based on the ACBS Task Force Report and new research findings, we suggest that ACT research may be entering a new era of personalized and process-based intervention based on new “idionomic” forms of functional analysis.

BackgroundThe Process-Based Assessment Tool (PBAT), is an item pool showing promising results in assessing psychological processes of change relevant for both psychotherapy and research in its original English version. However, further research focusing on translation and validation in other languages is needed for broader applicability. This study aims to translate and validate the PBAT in Swedish, and to examine the relationship with common clinical outcome variables. MethodsThe PBAT and STOP-D were translated and culturally adapted to Swedish. The study included 427 Swedish-speaking participants recruited online, with a mean age of 48. The PHQ-4 and Single Item Stress Scale were used as criterion variables. Correlational analyses and the Boruta feature selection algorithm were employed for data analysis. ResultsThe translated PBAT demonstrated significant correlations with clinical outcomes, indicating its effectiveness in a Swedish context. Positive PBAT items correlated with higher vitality and health, while negative items were predictive of sadness, anxiety, and stress. The Boruta analysis highlighted the importance of specific PBAT items to different clinical outcomes, underscoring the tool's validity. ConclusionThe Swedish version of the PBAT shows strong validity and reliability in assessing psychological health. This study contributes to the cross-cultural applicability of the PBAT, offering a valuable tool for psychological assessment in the Swedish context.

Although divorce rates are increasing in Japan, studies on the relationships of Japanese couples are lacking. This is the first empirical study on couples therapy in Japan. We developed Contextual Couples Therapy (CCT), a principle-based intervention comprising two sessions for Japanese couples. We evaluated the efficacy and feasibility of the intervention in a randomized controlled trial. A total of 36 individuals (18 couples) were randomly assigned to CCT (n = 16) and waitlist control conditions (n = 20). Couples were assessed at pre- and post-treatment and 1- and 3-month follow-ups using the Couples Satisfaction Index. The results indicated that CCT significantly improved the quality of relationships, and the effects were maintained at 1- and 3-month follow-ups. The findings on the satisfaction and acceptability of CCT are encouraging for conducting full-scale randomized control trials.

Parental psychological inflexibility, particularly characterized by experiential avoidance, represents a significant risk factor for chronic stress and psychological distress. The Parental Acceptance and Action Questionnaire (PAAQ) is a context-specific instrument for the measurement of parental psychological inflexibility. This study aimed to evaluate the psychometric properties of the original composite version of the 19-item PAAQ across the three distinct Swedish samples; a community sample (n = 1018), a clinical sample of treatment-seeking parents of children with disabilities (n = 667), and a test-retest sample (n = 337). The Principal Axis Factoring of the PAAQ in the community sample yielded a 16-item, three-factor solution: 1) action-taking and flexibility in the parenting context, 2) experiential acceptance of internal experiences related to parenting, and 3) experiential acceptance of child's internal experiences. This factor model was supported by the confirmatory factor analysis in the test-retest sample. The associations observed with related constructs (r = between 0.49 and 0.61, p < 0.0001) indicated good discriminant validity. The Receiver Operator Characteristic analysis demonstrated that the PAAQ can effectively classify between the clinical and community sample, achieving 79% sensitivity and 68% specificity. The showed good test-retest reliability (r = 0.82). As anticipated, the parents in the clinical sample showed greater psychological inflexibility compared to parents in the community sample. To conclude, the 16-item Swedish version of the PAAQ demonstrates adequate to good psychometric qualities.

This study evaluated idionomic methods for identifying within-person links between therapeutically relevant processes and outcomes, using an ecological momentary assessment dataset of valued action and hedonic well-being (participants (n) = 425; 71.76% female; age = M(SD) = 22.20 (6.85); sampling design: 3–4 prompts per day; total measurements (n) = 6456). We compared the idionomic approach, integrating idiographic and nomothetic insights, with traditional multilevel modeling (MLM). Our methods included idiographic autoregressive integrative moving average models with an exogenous variable (i-ARIMAX), multivariate random-effects meta-analysis (RE-MA), deep Gaussian mixture modeling (DGMM), and multilevel vector autoregression modeling (Multilevel-VAR). The results showed that i-ARIMAX outperformed MLM in capturing within-person heterogeneity in the links between valued action and affect variables. Increases in values-based living were positively related to hedonic well-being but this effect showed a high degree of heterogeneity. A sub-group was identified, which we labeled the ‘Stoics,’ whose daily engagement in valued actions did not produce higher hedonic well-being (e.g., lower sadness or higher joy). Multilevel-VAR further revealed that for Stoics, stressful situations were linked to valued action, but not hedonic well-being. For Non-Stoics, valued action was less likely in stressful situations, but when valued action did occur it was associated with more joy and less sadness. The study offers initial evidence suggesting the superiority of an idionomic approach over a purely nomothetic one in capturing diverse pathways to clinically relevant outcomes. Idionomic methods may be useful or even necessary in personalizing psychological interventions, and thus may need to be considered by researchers and practitioners alike.