Nutraceuticals and phytoceuticals in the treatment of schizophrenia: a systematic review and network meta-analysis.

Background: Sub-optimal response in schizophrenia is frequent, warranting augmentation strategies over treatment-as-usual (TAU). Methods: We assessed nutraceuticals/phytoceutical augmentation strategies via network meta-analysis. Randomized controlled trials in schizophrenia/schizoaffective disorder were identified via the following databases: PubMed, MEDLINE, EMBASE, Scopus, PsycINFO, CENTRAL, and ClinicalTrials.gov. Change (Standardized Mean Difference=SMD) in total symptomatology and acceptability (Risk Ratio=RR) were co-primary outcomes. Secondary outcomes were positive, negative, cognitive, and depressive symptom changes, general psychopathology, tolerability, and response rates. We conducted subset analyses by disease phase and sensitivity analyses by risk of bias and assessed global/local inconsistency, publication bias, risk of bias, and confidence in the evidence. Results: The systematic review included 49 records documenting 50 studies (n=2,384) documenting 22 interventions. Citicoline (SMD=-1.05,95%CI=-1.85; -.24), L-lysine (SMD=-1.04,95%CI=-1.84;-.25), N-acetylcysteine (SMD=-.87,95%CI=-1.27;-.47) and sarcosine (SMD=-.5,95%CI=-.87-.13) outperformed placebo for total symptomatology. High heterogeneity (tau Conclusions: Sarcosine, citicoline, and N-acetylcysteine are promising augmentation interventions in stable patients with schizophrenia, yet the quality of evidence is low to very low. Further high-quality trials in acute phases/specific outcomes/difficult-to-treat schizophrenia are warranted.