Effects of mindfulness-based interventions (MBIs) on psychotic symptoms and psychological outcomes in patients with schizophrenia spectrum disorders: A systematic review and meta-analysis.

Objective: Mindfulness refers to the practice of consciously attending to the present moment without judgement. Although mindfulness-based intervention have been extensively researched. Less is known about the effect of this intervention on psychotic symptoms in patients with schizophrenia spectrum disorders. Thus, we synthesized the effects of mindfulness-based interventions (MBIs) on psychotic symptoms, global functioning, insight, and mindfulness in patients with schizophrenia spectrum disorders.

Method: Nine electronic databases were searched from inception to March 2024 including Academic Search Complete, CINAHL, Cochrane, Ovid APA InFo, ProQuest, PubMed, Scopus, Mindfulness Journal and Web of Science. We reviewed studies on outcomes for patients with schizophrenia spectrum disorders receiving mindfulness-based interventions. We only reviewed all experimental and quasi-trials studies written in English. A random-effects model was used to compute the effect size. We used Funnel plot, Q statistics, and I to test the heterogeneity across studies. Also, we examined moderators to explore sources of heterogeneity.

Results: Across 24 included studies (N = 1,632), 796 schizophrenia patients participated in mindfulness interventions; 836 served as controls. Most schizophrenia patients were males (69 %, s = 7). Mean age ranged from 24.4 to 59.5 years. Overall, mindfulness-based interventions showed reduced psychotic symptoms (g = 0.70, 95 %CI 0.04, 1.36, I = 96 %), increased global functioning (g = 1.28, 95 %CI 0.50, 2.05), insight (g = 1.21, 95 %CI 0.88, 1.55) and mindfulness (g = 0.56, 95 %CI 0.15, 0.97) compared to control groups, but with substantial heterogeneity. With subgroup analysis, every one-year of mean age of patients with schizophrenia increased, psychotic symptom worsened (slope = -0.071, tau = 0.77, Q = 166.3, p = .016). Additionally, for every day of MBIs practice increased, psychotic symptoms improved (Slope = 0.012, tau = 1.37, Q = 251.6, p = .033), patients' functioning improved (slope = 0.013, tau2 = 0.69, Qbetween = 142.1, p = .017) and patients' insight improved (slope = 0.001, tau = 0.012, Q = 8.6, p = .043). Providing MBIs as a mixed format (individual plus group intervention) had a greater effect (g = 1.538) on improving patients' insight than providing MBIs only to individuals (g = 0.889). Also, providing MBIs with a home assignment had a greater effect (g = 1.517) on improving patients' insight than providing MBIs without a home assignment (g = 0.787). No primary studies reported the adverse effects.

Conclusion: MBIs significantly improved psychotic symptoms, global functioning, insight, and mindfulness among patients with schizophrenia spectrum disorders, especially MBIs with home assignment. Clinicians and health providers should consider using MBIs as alternative complementary treatment for improving psychotic symptoms and increasing global functioning, insight and mindfulness.