Testing the Effectiveness of Process Based Therapy in Routine Patient Care and Assessing Its Influence on Therapist Decision Making (PBACE)

Process Based Therapy Applicability, Effectiveness and Compatibility (PBACE). A Within Therapist Randomized Controlled Trial Testing the Effectiveness of Process Based Therapy in Routine Patient Care and Assessing Its Influence on Therapist Decision Making

Background: Process Based Therapy (PBT) is a novel approach for a more personalized psychotherapy by integrating patient's ecological momentary assessment (EMA) data into treatment planning and focusing on empirically measured maladaptive processes. Previous pilot studies have examined the efficacy and feasibility of PBT in different settings. However, the effectiveness of this approach as well as the influence of providing EMA data on therapist's decision-making as well as treatment planning is yet unexplored.

Objective: This study aims to evaluate the effectiveness of PBT in a naturalistic setting as well examine the influence of the provision of EMA data on therapists' decision-making.

Methods: Thiry therapists as well as 60 patients will be recruited. Therapists will each treat two patients which are randomly allocated to either an intervention group receiving PBT or an active control group receiving routine psychotherapy. Treatment outcomes will be measured pre and post treatment as well as a 6-month follow-up. Therapists' decision making will be measured before training in PBT as well as during the treatment process using think aloud protocols (TAP) as well as quantitative measurements for decision making styles and self efficacy in decision making.

Discussion: This study could add insights into the ongoing research about the efficacy and effectiveness of PBT as well as provide insights into therapists' treatment decisions. While PBT holds theoretical promise for a more personalized and effective treatment, empirical data is still needed to assess its theoretical merit, which this study could provide. Expanding on the thus far scarce literature on decision-making in the therapeutic process, valuable information about processes guiding therapists' treatment decisions could be gained.

Study Overview

• Status: Recruiting
• Conditions: Depressive and Anxiety Disorders
• Intervention / Treatment: Other: Process Based Psychotherapy (PBT); Drug: Psychiatric medication kept constant over study duration; Other: Routine practice

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Ulrich Stangier, PhD; Phone Number: 049 1707339293; Email: stangier@psych.uni-frankfurt.de

Study Locations

• Germany
  • Hesse
    • Frankfurt am Main, Hesse, Germany, 60486
      • Recruiting
      • JWGUniversity
      • Contact: Ulrich Stangier Research Professor, PhD; Phone Number: +491707339293; Email: stangier@psych.uni-frankfurt.de
      • Principal Investigator: Ulrich Stangier, PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• A primary ICD-11 diagnosis of a depressive or anxiety disorder
• Age 18-65 years
• Sufficient knowledge of the German language
• Participating patients are not required to discontinue medication, but to keep medication constant over the treatment period

Exclusion Criteria:

• Increased suicidality
• Substance abuse or dependency
• diagnosis of a cluster A or B (DSM-5) personality disorder
• pervasive developmental disorder, psychotic disorder, eating disorder, bipolar disorder, or severe physical illness.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Process Based Psychotherapy (PBT); In PBT, treatment planning is based on a dynamic network analysis of EMA data collected during the baseline phase. Therapists identify the central node, significant edges, self-loops, and feedback loops between the nodes. Using this information, interventions are selected based on empirical evidence for mechanisms of change that correspond to the network characteristics. These interventions are framed within an evolutionary framework as the variation, selection, and retention of an adaptive mode of the central node in relation to the specific context of the problem. The change in this key variable is monitored through daily judgments based on EMA. Treatment also focuses on additional targets to establish adaptive modes of the dimensions as defined in the positive network model. Concomitant medication is allowed and will be controlled by the study design.	Other: Process Based Psychotherapy (PBT); Intervention planning based on the use of EMA data, feedback of dynamic network analysis and matching of interventions to central nodes of the network.; Other Names: Process-based Therapy with Ecological Momentary Assessment; Drug: Psychiatric medication kept constant over study duration; Psychiatric medication is kept constant during the trial. Participants are not required to take medication. If participants enlisting in the trial are on medication however, they will be asked to keep medication constant over the study duration
Active Comparator: Routine practice (r-PT); In r-PT, as opposed to PBT, a naturalistic setting is retained for treatment decisions. Treatment planning follows traditional theories about the factors maintaining the disorder and interventions changing them, e.g. avoidance and exposure in anxiety disorders or reduced reinforcement of activities and behavioral activation in depression. Interventions are based on common treatment manuals related to diagnoses, e.g. CBT for depression. Individual data from the behavioral analysis are used to tailor the techniques to the individual problems of the patients. Treatment process is largely structured by personal preferences of the therapist due to experience, knowledge or recommendations of the National guidelines for the mental health problem.Concomitant medication is allowed and will be controlled by the study design.	Drug: Psychiatric medication kept constant over study duration; Psychiatric medication is kept constant during the trial. Participants are not required to take medication. If participants enlisting in the trial are on medication however, they will be asked to keep medication constant over the study duration; Other: Routine practice; Intervention planning as usual.; Other Names: Routine psychotherapy

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Depressive and anxiety symptom severity	To assess Psychopathological Stress , the Depression Anxiety Stress Scale 21 (DASS-21) is used. The DASS-21 is a validated and reliable 21 item self-report instrument for the measurement of depressive and anxiety symptoms. Additionally, stress as a negative affective state is measured on an additional subscale. The scale ranges from 1-4 with higher mean values reflecting higher symptom severity in the respective subscale as well as an overall score of Psychopathological Stress.	Assessed after randomization (Day 1), after completion of the EMA baseline phase (6-Week intermediate), assessed at post-treatment (week 28) and assessed at a six-month follow-up.
Positive Mental Health and Quality of Life	Positive mental health and quality of Life will be measured using the positive mental health scale (PMH). The PMH is a validated nine-item self-report scale for the measurement of the presence of positive mental health. Scores range form 1-4 with higher mean scores reflecting a more positive mental health.	Assessed after randomization (Day 1), after completion of the EMA baseline phase (6-Week intermediate), assessed at post-treatment (week 28) and assessed at a six-month follow-up.
Therapist Decision Making	Therapist Decision Making regarding treatment planning will be measured using think-aloud protocols (TAP). The think-aloud method is usually used to measure decision making in cognitive tasks such as problem solving, where participants are instructed to "think-aloud" meaning to verbalize their thoughts during a cognitive task. In this study, therapists will be instructed to verbalize their treatment planning at nine measurement points.	Assessed pre-training in PBT (Day 0), at Day 1 of treatment, after diagnosis (Day 2), after a hypothetical model is developed (Day 3), after EMA-Assessment is complete (Week-6) and every four weeks during the treatment phase (Weeks 10, 14, 18 and 22).

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Client satisfaction	Patient satisfaction at the end of treatment, measured with the Client Satisfaction Questionnaire (CSQ). The CSQ uses 8 items with a range of 1-4 with higher mean values reflecting higher satisfaction with the recieved treatment.	Assessed at post-treatment (week 28).
Patient and Therapist Attitude Towards EMA-Assessment	the therapist attitudes toward the utility of the EMA and networks scale (TAUEN) and the patient attitudes toward the utility of the EMA and networks scale (PAUEN) are modified versions of the Therapist and Client Attitudes Measures. minimum value= 8, maximum value= 40, higher scores mean a higher attitude toward EMA and networks regarding their utility.	Assessed at intermediate (week 6) and post-treatment (week 28) (PAUEN). Assessed at intermediate (week 6) and every four weeks in Treatment Phase (Weeks 10, 14, 18 and 22) (TAUEN)
Therapist Treatment Evaluation	The Treatment Evaluation Inventory will be used to assess therapists' perceptions of treatment. It consists of 14 statements that are evaluated on a 7-point Likert scale, with response options spanning from -3 (strongly disagree) to +3 (strongly agree). A higher mean score reflects a higher attitude towards the given treatment (e.g. PBT or routine care)	Assessed at intermediate (week 6) and every four weeks in the treatment phase (Weeks 10, 14, 18 and 22).
Self-Efficacy	Perceived general self-efficacy, meaning an optimistic self-belief that one can perform difficult or novel tasks or cope with adversity is measured by the General Self-Efficacy Scale (GSE). The GSE is a 10-item self-report questionnaire with a validated one factor structure. The GSE ranges from 1-4 with a higher mean score reflecting higher self-efficacy.	Assessed after randomization (Day 1), after completion of the EMA baseline phase (6-Week intermediate), assessed at post-treatment (week 28) and assessed at a six-month follow-up.
Decisional Self-Efficacy	Decision making self-efficacy is measured using the Decision Self-Efficacy Scale. The DSE is an 11-item self-report instrument measuring self-efficacy in the domain of treatment decisions. The DSE ranges from 0-4 with higher mean scores reflecting a higher confidence and self-efficacy in treatment decisions.	Assessed after randomization (Day 1), after completion of the EMA baseline phase (6-Week intermediate), assessed at post-treatment (week 28) and assessed at a six-month follow-up.
Therapeutic Alliance	Therapeutic Alliance is measured at patient level using the Working Alliance Inventory Short Revised Patient Version (WAI-SR-P). The WAI-SR-P measures therapeutic alliance from the patient's perspective using 12 items as a self report ranging from 1-5 with higher mean scores reflecting a stronger and more positive working alliance as perceived by the patient.	Assessed after randomization (Day 1), after completion of the EMA baseline phase (6-Week intermediate) and assessed at post-treatment (week 28).
Therapist Decision Making Style	Therapists' Decision Making Styles will be measured using the therapist decision making questionnaire (TDMQ). The TDMQ is a self-report scale measuring therapists' decision-making style using 23 items on a scale from 1 to 5. Higher mean scores on a specific subscale reflect a decision style that puts a higher emphasis on the sources of information belonging to that specific decision making style.	Assessed pre-training in PBT (Day 0), at Day 1 of treatment, after diagnosis (Day 2), after a hypothetical model is developed (Day 3), after EMA-Assessment is complete (Week-6) and every four weeks during the treatment phase (Weeks 10, 14, 18 and 22).

Collaborators and Investigators

• Sponsor: Goethe University
• Investigators: Principal Investigator: Ulrich Stangier, PhD, Goethe Universität Frankfurt

Publications and helpful links

General Publications

• Attkisson CC, Zwick R. The client satisfaction questionnaire. Psychometric properties and correlations with service utilization and psychotherapy outcome. Eval Program Plann. 1982;5(3):233-7. doi: 10.1016/0149-7189(82)90074-x.
• Wilmers, F., & Munder, T. (2016). Der WAI-sr. In K. Geue, B. Strauß, & E. Brähler (Hrsg.), Diagnostische Verfahren in der Psychotherapie (3. Aufl.). Hogrefe.
• Someren, M. W. van, Barnard, Y. F., & Sandberg, J. A. (1994). The think aloud method: A practical guide to modelling cognitive processes. Academic Press.
• Schwarzer, R., & Jerusalem, M. (2012). General Self-Efficacy Scale [Dataset]. https://doi.org/10.1037/t00393-000
• Lukat, J., Margraf, J., Lutz, R., Van Der Veld, W. M., & Becker, E. S. (2019). Positive Mental Health Scale [Dataset]. https://doi.org/10.1037/t74178-000
• Lovibond, S. H., & Lovibond, P. F. (2011). Depression Anxiety Stress Scales [Dataset]. https://doi.org/10.1037/t01004-000
• Frumkin MR, Piccirillo ML, Beck ED, Grossman JT, Rodebaugh TL. Feasibility and utility of idiographic models in the clinic: A pilot study. Psychother Res. 2021 Apr;31(4):520-534. doi: 10.1080/10503307.2020.1805133. Epub 2020 Aug 24.
• Fiehn, H. (n.d.). The Therapist Decision Making Style Questionnaire. [Manuscript in preparation].
• Burgio LD, Sinnott J. Behavioral treatments and pharmacotherapy: acceptability ratings by elderly individuals in residential settings. Gerontologist. 1990 Dec;30(6):811-6. doi: 10.1093/geront/30.6.811.
• Bunn H, O'Connor A. Validation of client decision-making instruments in the context of psychiatry. Can J Nurs Res. 1996 Fall;28(3):13-27.

Helpful Links

• University Website

Study record dates

Study Major Dates

• Study Start (Estimated): June 27, 2026
• Primary Completion (Estimated): January 1, 2029
• Study Completion (Estimated): January 1, 2029

Study Registration Dates

• First Submitted: June 22, 2026
• First Submitted That Met QC Criteria: July 9, 2026
• First Posted (Actual): July 15, 2026

Study Record Updates

• Last Update Posted (Actual): July 15, 2026
• Last Update Submitted That Met QC Criteria: July 9, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: effectiveness; Process Based Therapy
• Additional Relevant MeSH Terms: Mental Disorders; Anxiety Disorders; Behavioral Disciplines and Activities; Psychological Tests; Ecological Momentary Assessment
• Other Study ID Numbers: 2026-00-PBACE

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Individual participant data that underlie the results reported in the main publication of outcomes, after deidentification (text, tables, figures, and appendices) will be shared. Further Study Protocol, Analysis Plan, Informed Consent Form and Analytic Code will be shared to researchers who provide a methodologically sound proposal.
• IPD Sharing Time Frame: Beginning 3 months and ending 5 years following article publication. Data are available for 5 years at the Open Science Forum under: https://doi.org/10.17605/OSF.IO/TVKMQ
• IPD Sharing Access Criteria: Proposals should be directed to stangier@psych.uni-frankfurt.de. To gain access, data requestors will need to sign a data access agreement.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No