Comparative Effects of Exercise Modalities on Negative Symptoms in Schizophrenia: A Systematic Review and Network Meta-analysis of 32 RCTs

Abstract

Background: Negative symptoms of schizophrenia are poorly responsive to antipsychotics and markedly reduce quality of life. Exercise may offer an adjunctive non-pharmacological strategy, yet the relative efficacy of different exercise types remains unclear.

Objective: To compare the effectiveness of aerobic exercise (AE), resistance exercise (RE), combined aerobic-plus-resistance (AE+RE), mind-body exercise (MBE) and yoga for improving negative symptoms in adults with schizophrenia.

Methods: Five databases were searched from inception to September 2024 for randomised controlled trials comparing any structured exercise with control (no/minimal exercise) or another exercise modality in adults with schizophrenia. Primary outcome was change in negative-symptom scores (PANSS-negative, SANS or BNSS). Two reviewers independently selected studies, extracted data and assessed risk of bias (ROB). Pooled standardised mean differences (SMD) and 95 % confidence intervals (CI) were generated in random-effects pairwise and network meta-analyses. SUCRA probabilities ranked interventions. GRADE assessed certainty of evidence.

Results: Thirty-two RCTs involving 1773 participants from Asia (n = 23), Europe (n = 6), North America (n = 2) and South America (n = 1) were included. Intervention duration ranged 4-24 weeks (median 12 weeks). All exercise types improved negative symptoms versus control: Yoga SMD = -1.14 (95 % CI -1.54, -0.75); Resistance exercise SMD = -1.15 (95 % CI -1.96, -0.34); Aerobic exercise SMD = -0.79 (95 % CI -1.13, -0.46); Mind-body exercise SMD = -0.53 (95 % CI -1.02, -0.03); Combined AE+RE SMD = -0.57 (95 % CI -1.17, 0.04). SUCRA rankings (higher = more effective): Yoga 87.1 %, Resistance 82.1 %, Aerobic 56.9 %, Combined 38.5 %, Mind-body 34.4 %. Subgroup analyses showed larger benefits in participants aged 31-40 years (p = 0.022) and in studies conducted in Asia (p = 0.022). Network geometry was well connected; no significant inconsistency or small-study effects were detected. GRADE certainty was low for most direct and indirect comparisons, moderate for SUCRA-based rankings.

Conclusions: Low- to moderate-certainty evidence indicates that yoga and resistance exercise confer the greatest improvements in negative symptoms of schizophrenia. Age and geographical setting modify treatment effects, suggesting the need for personalised exercise prescription. Larger, high-quality RCTs are warranted to confirm these findings.

Keywords: Exercise; Negative symptoms; Network meta-analysis; RCTs; Schizophrenia.