Background: Mindfulness-based interventions (MBIs) have emerged as secular practices, including elements of mindfulness-based stress reduction (MBSR) and mindfulness-based cognitive therapy (MBCT). While MBIs have been widely adopted for physical and mental illness, only a few available programs are explicitly adapted for psychosis. However, previous reviews have reported the vital heterogeneity regarding treatment program structure. Therefore, this review aims to compare the structure of different mindfulness protocols applied to patients with schizophrenia spectrum disorder (SSD).

Methods: A systematic search was conducted up to March 2023 in PubMed, Embase and PsycInfo. Following our protocol (CRD 42023253356), we followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) checklist.

Results: We included 22 randomized controlled trials (RCTs) involving 1500 patients SSD. All programs varied in structure, session components, duration, and instructor experience. While MBSR-like programs focused on stress reactivity, MBCT-like programs addressed primary symptoms of psychosis and relapse prevention. Despite the heterogeneity of programs, some common mechanisms emerged, including attention training, emotion and stress regulation, decentering, self-compassion, and cognitive restructuring.

Conclusions: The critical heterogeneity found limits the interpretation of results. However, most recent trials present fewer risks of bias and more homogenous programs. Findings suggested potential benefits, such as reduced negative symptoms, increased well-being, and decreased hospitalization rates. For future studies, authors should align on more congruent MBIs programs for patients with SSD. Further research is needed to identify optimal mindfulness teaching approaches for patients with psychosis and investigate specific mechanisms of action, relevant processes, and optimal doses in varying settings.