Music therapy for improving mental health in offenders: protocol for a systematic review and meta-analysis

This is a protocol for a systematic review of the effects of music therapy on offenders. Based on randomised controlled trials, the review aims to assess the effectiveness of music therapy on adolescent and adult offenders in custodial institutions including forensic psychiatric hospitals, and offenders or probationers in the community. The outcomes to be evaluated include alleviated symptoms of mental illness, psychosocial competencies and reduced recidivism.

💡 Research Summary

This paper presents a detailed protocol for a systematic review and meta‑analysis that will evaluate the effectiveness of music therapy for improving mental health outcomes among offenders. The review will focus on randomized controlled trials (RCTs) involving adolescent and adult offenders who are incarcerated in prisons, detained in forensic psychiatric hospitals, or supervised in the community as probationers or parolees. The primary objectives are threefold: (1) to determine whether music therapy reduces symptoms of mental illness such as depression, anxiety, and post‑traumatic stress disorder; (2) to assess its impact on psychosocial competencies including emotional regulation, interpersonal skills, and self‑efficacy; and (3) to examine whether participation in music therapy is associated with lower rates of recidivism, re‑incarceration, or probation violations.

Methodological Framework
The protocol follows the Preferred Reporting Items for Systematic Review and Meta‑Analysis (PRISMA) guidelines and adopts a PICO (Population, Intervention, Comparison, Outcome) structure to ensure clarity and reproducibility. The population includes individuals aged 12 years and older who are either incarcerated, detained for forensic psychiatric reasons, or under community supervision. The intervention is defined as a structured music‑therapy program delivered by a qualified music therapist; programs may involve active music making, improvisation, songwriting, or receptive listening, but must be clearly described in the primary study. Comparators may be wait‑list controls, treatment‑as‑usual (e.g., standard counseling or pharmacotherapy), or alternative psychosocial interventions.

Search Strategy and Study Selection
A comprehensive search will be conducted across major biomedical and psychological databases—MEDLINE (via PubMed), PsycINFO, Embase, CINAHL, and the Cochrane Central Register of Controlled Trials—from the year 2000 to the present. The search terms combine controlled vocabulary and free‑text keywords such as “music therapy,” “offender,” “prison,” “forensic,” “recidivism,” and “mental health.” Grey literature will be captured through searches of trial registries (ClinicalTrials.gov, WHO ICTRP), dissertations, conference proceedings, and relevant governmental reports to mitigate publication bias. Two independent reviewers will screen titles and abstracts, retrieve full texts for potentially eligible studies, and resolve disagreements through discussion or a third reviewer. A PRISMA flow diagram will document the selection process.

Data Extraction and Risk‑of‑Bias Assessment
Data extraction will be performed independently by two reviewers using a pre‑piloted form that captures study characteristics (year, country, sample size, demographic details), intervention specifics (duration, frequency, modality), comparator details, outcome measures, follow‑up periods, and attrition rates. The Cochrane Risk of Bias 2.0 tool will be employed to evaluate five domains: randomization process, deviations from intended interventions, missing outcome data, measurement of the outcome, and selection of reported results. Each domain will be rated as “low risk,” “some concerns,” or “high risk.”

Statistical Analyses
For continuous outcomes (e.g., symptom scales), standardized mean differences (SMD) with 95 % confidence intervals will be calculated; for dichotomous outcomes (e.g., recidivism), risk ratios (RR) will be used. Heterogeneity will be quantified using the I² statistic and Cochran’s Q test. An I² value greater than 50 % will trigger the use of a random‑effects model; otherwise, a fixed‑effect model will be applied. Subgroup analyses are planned to explore potential moderators such as age group (adolescent vs. adult), setting (prison vs. forensic hospital vs. community), therapy intensity (number of sessions, total contact hours), and type of music‑therapy modality (active vs. receptive). Meta‑regression may be conducted if a sufficient number of studies (>10) are available. Publication bias will be examined through funnel‑plot asymmetry and Egger’s regression test. Sensitivity analyses will exclude studies at high risk of bias and assess the influence of each individual study on the pooled effect size.

Anticipated Contributions and Limitations
If the meta‑analysis demonstrates that music therapy yields statistically and clinically significant reductions in mental‑health symptomatology and improves psychosocial functioning, it could substantiate the inclusion of music‑based interventions in correctional health policies. Moreover, evidence of reduced recidivism would have profound implications for public safety and correctional cost‑effectiveness, supporting a shift toward rehabilitative, rather than purely punitive, models. However, the protocol acknowledges several constraints: the scarcity of high‑quality RCTs in custodial settings may limit statistical power; variability in therapeutic content (genre, improvisational vs. scripted approaches) and therapist qualifications could introduce heterogeneity that is difficult to fully account for; and the relatively short follow‑up periods typical of prison‑based studies may impede assessment of long‑term outcomes such as sustained desistance from crime.

Conclusion
This protocol outlines a rigorous, transparent, and reproducible approach to synthesizing the existing evidence on music therapy for offender populations. By systematically collating data on mental‑health symptom reduction, psychosocial skill development, and recidivism, the forthcoming review aims to fill a critical knowledge gap and provide actionable insights for clinicians, correctional administrators, and policymakers seeking evidence‑based, humane, and cost‑effective interventions within the criminal justice system.