A transdiagnostic group exercise intervention for mental health outpatients in Germany (ImPuls): results of a pragmatic, multi-site, block-randomised, phase 3 controlled trial
Authors: Wolf Sebastian , Seiffer Britta , Zeibig Johanna-Marie , Frei Anna Katharina , Studnitz Thomas , Welkerling Jana , Meinzinger Edith , Bauer Leonie Louisa , Baur Julia , Rosenstiel Stephanie , Fiedler David Victor , Helmhold Florian , Ray Andreas , Herzog Eva , Takano Keisuke , Nakagawa Tristan , Günak Mia Maria , Kropp Saskia , Peters Stefan , Flagmeier Anna Lena , Zwanzleitner Lena , Sundmacher Leonie , Ramos-Murguialday Ander , Hautzinger Martin , Sudeck Gorden , Ehring Thomas 
Published: December 2023

Background

This study aimed to assess the efficacy of ImPuls, a transdiagnostic group exercise intervention, plus treatment as usual (TAU) compared to TAU alone in outpatients with various mental disorders.

Methods

In this pragmatic, two-arm, multi-site randomised controlled trial in Germany, 10 outpatient rehabilitative and medical care facilities were involved as study sites. Participants were outpatients diagnosed according to ICD-10 with one or more of the following disorders based on structured clinical interviews: major depression, primary insomnia, PTSD, panic disorder, or agoraphobia. Blocks of six participants were randomly allocated to ImPuls plus TAU or TAU alone, stratified by study site. TAU was representative of typical outpatient health care in Germany, allowing patients access to any standard treatments. The primary outcome was global symptom severity at 6 and 12 months after randomisation, measured using self-report on the Brief Symptom Inventory (BSI-18) and analysed in the intention-to-treat sample. Safety was assessed in all participants. The trial was registered with the German Clinical Trials Register (ID: DRKS00024152, 05/02/2021).

Findings

Of the 400 eligible participants, 284 (71%) self-identified as female; mean age was 42·20 years (SD 13·23; range 19–65). 287 (71·75%) participants met the criteria for depression, 81 (20·25%) for primary insomnia, 37 (9·25%) for agoraphobia, 46 (11·50%) for panic disorder, and 72 (18%) for PTSD. 199 participants were allocated to the intervention and 201 to the control group. 38 (19·10%) participants did not receive the minimum ImPuls intervention dose. ImPuls plus TAU demonstrated superior efficacy to TAU alone in reducing global symptom severity, with an adjusted difference on BSI-18 of 4·11 (95% CI 1·74 to 6·48;d=0·35 [0·14–0·56]; p=0·001) at 6 months and 3·29 (95% CI 0·86–5·72;d=0·28 [0·07–0·50]; p=0·008) at 12 months.

Interpretation

ImPuls is an efficacious transdiagnostic adjunctive treatment in outpatient mental health care.

Research in context

Evidence before this study

There is strong evidence that exercise interventions are efficacious in reducing the symptoms of a range of highly prevalent mental disorders, including depression, insomnia, agoraphobia, panic disorder, and post-traumatic stress disorder (PTSD). Most research to date, however, has focused on disorder-specific outcomes and interventions in patient samples with specific mental disorders. In contrast, there is a lack of evidence on transdiagnostic exercise interventions and their effects on global symptom severity in samples of patients with various mental disorders. Furthermore, evidence on the disorder-specific effects of exercise interventions is mostly based on studies without long-term follow-up assessments and with small sample sizes, making it difficult to draw strong conclusions about their long-term efficacy.

Before conducting the present study, we searched PubMed in March 2020 without date or language restrictions using the following search terms: ((exercise[Title/Abstract]) OR (physical activity[Title/Abstract])) AND ((transdiagnostic[Title/Abstract])) AND ((intervention) OR (treatment)) AND ((depression) OR (anxiety) OR (panic) OR (agoraphobia) OR (insomnia) OR (PTSD)). Our search had no date or language restrictions, and it used the filter for randomised controlled trials. Three relevant papers were identified: two consisted of study protocols published in 2015 and 2016, and one from 2017 reported the results of a clinical trial. The study protocols described trials designed to evaluate the efficacy of transdiagnostic interventions in which physical activity constituted only one component. The clinical trial investigated the effects of exercise and strength training on disorder-specific and transdiagnostic outcomes, albeit only in patients with anxiety-related disorders.

Added value

Our large randomised controlled trial assessed the efficacy of a group exercise intervention (ImPuls) plus treatment as usual (TAU) compared to TAU alone in reducing global transdiagnostic symptom severity in a real-world outpatient context for adult patients diagnosed with depression, insomnia, agoraphobia, panic disorder, or PTSD. Of the 400 patients successfully recruited to the study and randomised to the intervention or control group, 77% were already receiving a standard outpatient treatment (pharmacotherapy or psychological treatment) at baseline.

We found larger improvements in global symptom severity in the intervention group compared to control at 6 months after baseline, with persistent benefits seen at the 12-month follow-up assessment.

An evaluation of reliable clinical change showed that the effects were clinically meaningful both at 6 and 12 months. We also found indications of benefits for disorder-specific mental health symptoms, including those of depression, panic disorder, general anxiety, and PTSD. These clinical effects were maintained for depression, general anxiety, and panic disorder symptoms up to the 12-month assessment.

Mean self-reported exercise increased in the intervention group from 17 weekly minutes on average to the intended dose of more than 90 weekly minutes at 6 months and dropped to 69 minutes at 12 months. Increases in self-reported exercise partially explained the treatment effects for participants who adhered to the minimum intervention dose. After concluding this study in September 2023, we updated our literature search. Apart from our own feasibility study, however, we found no additional studies specifically evaluating the efficacy of exercise on global symptom severity in a sample of patients diagnosed with depression, insomnia, anxiety disorders, or PTSD, underscoring the novelty of our study. Our results provide strong evidence that exercise therapy is a feasible and efficacious transdiagnostic adjunctive treatment in real-world mental health care contexts for outpatients with various mental disorders.

Implications of all the available evidence

Strong evidence that exercise is efficacious in treating specific mental disorders, as well as new evidence from our study that exercise has transdiagnostic effects when combined with TAU, suggests that exercise therapy should be used in outpatient mental health care (a) as an alternative to standard treatment or (b) as an adjunctive treatment for disorders such as depression, insomnia, panic disorder, agoraphobia, and PTSD. Transdiagnostic group exercise interventions hold great promise because they allow for the simultaneous treatment of multiple patients. By optimizing the use of healthcare resources and potentially reducing waiting times for treatment, these interventions could ameliorate the existing disparity in care provision between the many individuals in need of evidence-based treatment and the few who are actually receiving it.