Transdiagnostic treatments span a heterogeneous group of interventions that target a wider range of disorders and can be applied to treat several disorders simultaneously. Several meta-analyses have highlighted the evidence base of these novel therapies. However, these meta-analyses adopt different definitions of transdiagnostic treatments, and the growing field of transdiagnostic therapies has become increasingly difficult to grasp. The current narrative review proposes a distinction of “one size fits all” unified and “my size fits me” individualized approaches within transdiagnostic therapies. Unified treatments are applied as “broadband” interventions to a range of disorders without tailoring to the individual, while individualized treatments are tailored to the specific problem presentation of the individual, e.g., by selecting modules within modular treatments. The underlying theoretical foundation and relevant empirical evidence for these different transdiagnostic approaches are examined. Advantages and limitations of the transdiagnostic treatments as well as future developments are discussed.

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Objectives The aim of the study was to assess the convergent and divergent validity, reliability, utility, and treatment sensitivity of a newly translated German version of the Southampton Mindfulness Questionnaire (SMQ). The SMQ is a 16-item instrument measuring mindful awareness of distressing thoughts, images, and perceptions, developed originally within the mindfulness for psychosis field. Methods Overall, three studies were conducted, comprising (1) a non-clinical sample of n = 848 (638 community sample and 210 meditators); (2) a clinical sample of n = 213 (106 schizophrenia and 107 depression); and (3) a clinical sample with n = 122 participants with emotional disorders within a randomized controlled study, of which 30 participants were also included in study 2. To assess convergent validity, participants completed the SMQ, Freiburg Mindfulness Inventory (FMI), and Comprehensive Inventory of Mindfulness Experiences (CHIME). To measure divergent validity, participants completed the Brief Symptom Inventory 18 (BSI-18), Positive and Negative Affect Schedule (PANAS), Brief Experiential Avoidance Questionnaires (BEAQ), and Anxiety Sensitivity Index 3 (ASI-3). Results Mean internal consistency (α = 0.89) and convergent (r = 0.66 to 0.73) and divergent validity (r = − 0.09 to − 0.50) were established and sensitivity to change over time following treatment (d = 0.86) was shown. For the clinical sample, a single-factor structure is suggested by principal component analysis. Conclusions Results provide first evidence for the utility of the German version of the SMQ for clinical practice and research in healthy individuals, meditators, and clinical groups. Further research is needed to examine the underlying construct of mindfulness.

The Brief Experiential Avoidance Questionnaire (BEAQ) is a 15-item short form of the Multidimensional Experiential Avoidance Questionnaire. This study aimed to investigate psychometric properties of a German translation of the BEAQ in a student and a clinical population. The BEAQ showed high internal reliability and overall acceptable convergent and discriminant validity. The BEAQ displayed adequate 7- to 13-day test–retest reliability and captured changes in experiential avoidance when experiential avoidance was targeted in treatment. Confirmatory factor analyses indicated that a bifactor structure where the BEAQ is modeled as one general and five specific factors that correspond to the Multidimensional Experiential Avoidance Questionnaire subscales fit the data adequately. All items (except Item 1 in the clinical population) loaded on the general factor and common variance was approximately equally spread across the general and specific factors. The Distress Endurance subscale was not included in this model, since it is represented by only one item, which showed poor performances and low associations to the BEAQ’s total score in both samples. We recommend further research into the BEAQ’s factor structure to substantiate our preliminary findings.

Background In blended therapy, face-to-face psychotherapy and Internet-based interventions are combined. Blended therapy may be advantageous for patients and psychotherapists. However, most blended interventions focus on cognitive behavioral therapy or single disorders, making them less suitable for routine care settings. Methods In a randomized controlled trial, we will compare blended therapy and face-to-face therapy in routine care. We intend to randomize 1152 patients nested in 231 psychotherapists in a 1:1 ratio. Patients in the blended therapy group will receive access to a therapeutic online intervention (TONI). TONI contains 12 transdiagnostic online modules suited for psychodynamic, cognitive behavioral, and systemic therapy. Psychotherapists decide which modules to assign and how to integrate TONI components into the psychotherapeutic process to tailor treatment to their patients’ specific needs. We will assess patients at baseline, 6 weeks, 12 weeks, and 6 months. Patients enrolled early in the trial will also complete assessments at 12 months. The primary outcomes are depression and anxiety at 6-month post-randomization, as measured by PHQ-8 and GAD-7. The secondary outcomes include satisfaction with life, level of functioning, personality traits and functioning, eating pathology, sexual problems, alcohol/drug use, satisfaction with treatment, negative effects, and mental health care utilization. In addition, we will collect several potential moderators and mediators, including therapeutic alliance, agency, and self-efficacy. Psychotherapists will also report on changes in symptom severity and therapeutic alliance. Qualitative interviews with psychotherapists and patients will shed light on the barriers and benefits of the blended intervention. Furthermore, we will assess significant others of enrolled patients in a sub-study. Discussion The integration of online modules which use a common therapeutic language and address therapeutic principles shared across therapeutic approaches into regular psychotherapy has the potential to improve the effectiveness of psychotherapy and transfer it into everyday life as well help save therapists’ resources and close treatment gaps. A modular and transdiagnostic setup of the blended intervention also enables psychotherapists to tailor their treatment optimally to the needs of their patients. Trial registration German Clinical Trials Register (DRKS) DRKS00028536. Registered on 07.06.2022.

Background Transdiagnostic treatments target shared mechanisms between disorders to facilitate change across diagnoses. The Unified Protocol (UP) aims at changing dysfunctional reactions towards emotions by increasing mindful emotion awareness and cognitive flexibility, as well as decreasing anxiety sensitivity and emotion avoidance. Method We investigated whether these transdiagnostic processes were malleable by treatment and mediated the relationship between treatment and outcome in an internet-delivered adaptation of the UP. N = 129 participants with mixed anxiety, depressive, and somatic symptom disorders were randomized to treatment or waitlist. Results The treatment yielded significant changes in all transdiagnostic processes over time in comparison to a waitlist condition. In separate mediator models, significant mediating effects were found for mindfulness, cognitive flexibility, behavioral activation, and experiential avoidance. When all mediators were combined in a multiple mediator model, the indirect effects through mindfulness and cognitive flexibility emerged as significant. Conclusion These findings add to the growing body of research on transdiagnostic processes as mediators of change and emphasize mindfulness and cognitive flexibility as a transdiagnostic treatment target. However, these results should be interpreted cautiously, as temporal precedence could not be established.

The Unified Protocol (UP) as a transdiagnostic intervention has primarily been applied in the treatment of anxiety disorders and in face-to-face-settings. The current study investigated the efficacy of a 10-week internet-based adaptation of the UP for anxiety, depressive, and somatic symptom disorders. N=132 participants were randomized to treatment or waitlist control. Linear mixed effect models revealed significant treatment effects for symptom distress, satisfaction with life, positive/negative affect and markers of anxiety, depression, and somatic symptom burden (within-group Hedges’ g = 0.32-1.38 and between-group g = 0.20-1.11). Treatment gains were maintained at 1- and 6-month-follow-up. Subgroup analyses showed comparable effects in participants with anxiety and depressive disorders. The results strengthen the application of the UP as an internet-based treatment for alleviating symptom distress across emotional disorders. More research on the applicability for single disorders and the mechanisms underlying the effects is needed.

The Unified Protocol (UP) as a transdiagnostic intervention has primarily been applied in the treatment of anxiety disorders and in face-to-face-settings. The current study investigated the efficacy of a 10-week Internet-based adaptation of the UP for anxiety, depressive, and somatic symptom disorders. The trial was registered under DRKS00014820 at the German Clinical Trial Registry, DRKS. Participants (n = 129) were randomized to treatment or waitlist control. Significant treatment effects were found for symptom distress, satisfaction with life, positive/negative affect and markers of anxiety, depression, and somatic symptom burden (within-group Hedges’ g = 0.32–1.38 and between-group g = 0.20–1.11). Treatment gains were maintained at 1- and 6-month-follow-up. Subgroup analyses showed comparable effects in participants with anxiety and depressive disorders. 26.6% dropped out of treatment and 35.38% did not provide post-treatment assessments. The results strengthen the application of the UP as an Internet-based treatment for alleviating symptom distress across emotional disorders. More research on the applicability for single disorders is needed and avenues to improve adherence and attrition rates should be explored.