Table 1

Additional outcome and process measures to assess changes in potential mechanisms of psychological distress and in response to specific transdiagnostic intervention modules

MeasureFocus area
The Treatment Credibility/Expectancy Questionnaire (CEQ)64 Expectancy about treatment outcome, as well as the credibility of the treatment
Cognitive Emotion Regulation Questionnaire (CERQ)65 Ability to contextualise negative events within a wider frame of reference
The Experiences Questionnaire (EQ)66 Ability to disengage from troublesome mental content and take a more accepting stance towards it, as well as the tendency to engage in rumination
Differential Emotions Scale (DES67)Intensity with which they experience different emotions on a typical day to obtain summary scores for positive emotions, negative emotions and denied emotions (the number of emotions not endorsed by the participant)
Levels of Personality Functioning Scale (LPFS)68 Personality functioning based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) alternative model of personality disorders. It has four subscales: identity, self-direction, empathy and intimacy
Ruminative Responses Scale of the Response Styles Questionnaire (RRS)69 Rumination (Module 7—Overcoming repetitive thinking)
Distress Tolerance Scale (DTS)70 Ability to tolerate distress (Module 3—Managing and tolerating emotions)
Difficulties with Emotion Regulation Scale (DERS)71 Ability to label, perceive and regulate emotions (Modules 2—Understanding emotions and 3—Managing and tolerating emotions)
Dysfunctional Attitudes Scale (DAS) short form (versions 1 and 2)72 Negative beliefs, thoughts and assumptions (Module 6—Tackling unhelpful thoughts)
Kentucky Inventory of Mindfulness Skills (KIMS)73 Mindful awareness (Module 2—Understanding emotions)
Anxiety Sensitivity Index (ASI)74 Fear of physical anxiety sensations (Module 3—Managing and tolerating emotions and Module 5—Tackling avoidance)
Post-traumatic Cognitions Inventory–short version (PTCI)75 Trauma-related beliefs and maladaptive appraisals of intrusive symptoms (Module 9—Managing upsetting memories and images)
Skills of Cognitive Therapy76 Implementation of cognitive therapy skills (Module 6—Tackling unhelpful thoughts)
The Multidimensional Experiential Avoidance Questionnaire77 Avoidance of internal experiences including thoughts, feelings, physical sensations (Module 5—Tackling avoidance)