Multidomain Lifestyle Intervention Shows Feasibility for Psychiatric Outpatients

People living with mental illness often face a double burden: the psychosocial challenges of their condition itself, and a cluster of somatic comorbidities such as cardiovascular disease, obesity and diabetes that shorten life expectancy and erode quality of life. At the same time, symptom-focused treatment frequently produces only limited response in this heterogeneous population. A new pilot randomized controlled trial published in BMC Psychiatry suggests that a carefully structured, multidomain lifestyle intervention adapted for psychiatric outpatients could offer a practical route toward recovery, and the researchers report that the program appears feasible and well received by a diverse sample of patients.

The intervention, known by the acronym CHAPTER, which stands for Combined Healthy lifestyle intervention Aimed at Psychiatric outpatients Targeting Enhanced Recovery, was designed to be transdiagnostic, meaning it was not tailored to a single psychiatric label but offered to outpatients across diagnoses, including depression, personality disorders and autism spectrum disorder. Rather than targeting one behavior, CHAPTER addressed eight lifestyle domains in an integrated way: physical activity, nutrition, relaxation, sleep, substance use, spirituality, social participation and nature. The recovery-oriented philosophy behind the design reflects a growing consensus in psychiatry that recovery is more than symptom reduction, encompassing personal, societal and functional dimensions of a patient’s life.

In the pilot trial, forty-six outpatients were randomized in a one-to-one ratio to either the intervention or treatment as usual. The intervention consisted of twelve weekly group sessions followed by three follow-up sessions, delivered by trained lifestyle coaches in specialist mental healthcare settings in the Netherlands. Outcomes were administered at baseline, post-intervention and follow-up, and the research team evaluated three categories of results: feasibility, measured through recruitment, retention and adherence; acceptability, assessed through participant evaluations and trainer feedback; and preliminary exploratory effectiveness, captured with self-report questionnaires and physical measurements across several recovery outcomes, including the Recovery Assessment Scale as the primary effect measure.

The feasibility results form the technical heart of the study. Intervention attendance reached seventy-one percent, a relatively high figure for a population often described as difficult to engage in group programs, and the dropout rate was just thirteen percent. Overall study retention, meaning participants who completed outcome assessments across all measurement points, stood at eighty-three percent. For a pilot trial in specialist mental healthcare, these numbers indicate that both the intervention protocol and the research procedures could be delivered in real-world clinical practice with minimal risks reported by trainers and participants.

Acceptability data reinforced that picture. Participants rated the intervention 7.4 out of 10, and they particularly valued the sessions on relaxation and spirituality. The content and its difficulty were reported as appropriate, suggesting the program struck a workable balance between accessibility and substance. Trainers, however, flagged organizational factors that require attention for broader implementation, including staff capacity, high workload and organizational instability within mental healthcare institutions. These findings matter because even a well-designed intervention can fail in practice if the surrounding organizational infrastructure cannot support it.

On preliminary effectiveness, the exploratory analyses suggested positive trends across various recovery domains, notably on the long term for societal and personal recovery. Participants in the intervention group showed encouraging movement on measures of recovery, quality of life and functioning compared with those receiving treatment as usual. The researchers were careful, however, to note that the effect estimates were imprecise, with ninety-five percent confidence intervals that included zeros, meaning the observed trends could reflect chance. These exploratory findings should be interpreted with caution, and the study was not powered to detect effectiveness with statistical certainty.

The technical design of the pilot reflects methodological rigor for an early-stage trial. The trial was preregistered on 30 May 2023 in the Overview of Medical Research in the Netherlands under registration number NL-OMON53239, with CCMO register number NL83935.042.23, and the research protocol was approved by the Medical Ethical Committee of the University Medical Centre Groningen. The research team used modern statistical approaches for handling missing data, including multiple imputation using chained equations and last observation carried forward, and they assessed determinants of implementation with the Measurement Instrument for Determinants of Innovations. Physical measurements included body mass index alongside self-report questionnaires such as the Outcome Questionnaire 45 and the World Health Organization Disability Assessment Schedule.

What makes this pilot noteworthy in the broader scientific conversation is its inclusive, transdiagnostic approach. Most lifestyle intervention studies in psychiatry focus on a single diagnosis, most commonly depression or psychosis, and on a single behavior, most commonly physical activity. By contrast, CHAPTER was offered to a heterogeneous sample of outpatients across diagnoses and targeted eight domains simultaneously. The researchers argue that this inclusive multidomain design appears feasible and well received, and that the results encourage further testing in a fully powered randomized controlled trial with a larger sample and longer follow-up.

The recovery-oriented framework underlying the intervention also deserves attention. The Recovery Assessment Scale, used as the primary effect measure, captures how patients themselves experience their recovery, including confidence in personal goals, willingness to seek help and the ability to manage symptoms in daily life. The positive long-term trends on societal and personal recovery align with the idea that lifestyle change can support functional and existential dimensions of wellbeing that symptom-focused treatment alone often leaves untouched. The particular appreciation for relaxation and spirituality sessions suggests that patients value domains that conventional psychiatric care rarely addresses in a structured group format.

As with any pilot study, the limitations are real. The sample of forty-six participants is small, the follow-up period is limited, and the imprecise effect estimates mean the preliminary effectiveness findings cannot yet be considered evidence of impact. Organizational barriers flagged by trainers, including workload and instability, also complicate the path to routine implementation. Still, the combination of high attendance, low dropout, strong retention and favorable participant ratings marks this study as a promising proof of concept. If a fully powered trial confirms the exploratory trends, multidomain lifestyle interventions could become a structured, recovery-oriented complement to standard psychiatric outpatient care, offering patients a way to work on sleep, movement, nutrition, connection and meaning alongside their regular treatment.

Subject of Research: A pilot randomized controlled trial of a transdiagnostic multidomain lifestyle intervention for psychiatric outpatients

Article Title: A pilot randomized controlled trial of a transdiagnostic multidomain lifestyle intervention for psychiatric outpatients: feasibility, acceptability and preliminary effectiveness for improving recovery

Article References: Schillemans, C., Castelein, S., Steffek, E., Booij, S. H., & Hoenders, H. J. R. (2026). A pilot randomized controlled trial of a transdiagnostic multidomain lifestyle intervention for psychiatric outpatients: feasibility, acceptability and preliminary effectiveness for improving recovery. BMC Psychiatry. https://doi.org/10.1186/s12888-026-08552-6

Image Credits: AI Generated

DOI: 10.1186/s12888-026-08552-6

Keywords: pilot, randomized, controlled, trial, transdiagnostic, multidomain, lifestyle, intervention, psychiatric, outpatients, feasibility, acceptability