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

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.

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.

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.

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.

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.

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)

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.

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.

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.

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.