Study Finds That Probiotics, Vitamin D May Enhance Cognitive Function in Schizophrenia


Researchers investigated the effects of this supplementation on cognitive function and disease severity in schizophrenia. Here’s what they found.

Valerii Honcharuk_AdobeStock

Valerii Honcharuk_AdobeStock

Investigators recently conducted a double-blinded randomized controlled trial to examine the impact of co-administering probiotics and vitamin D on cognitive function in patients with schizophrenia. The study delved into the potential synergistic effects of these supplements in addressing cognitive impairment associated with schizophrenia.1

“Manipulation of the intestinal microbiome and supplying vitamin D can attenuate psychiatric symptoms in schizophrenic patients,” the investigators wrote. “The current study tried to evaluate the effects of probiotic/vitamin D supplementation on the cognitive function and disease severity of schizophrenic patients.”

In the study, 70 individuals diagnosed with schizophrenia between ages 18 and 65 years were enlisted. They were randomly assigned to either the placebo group (n = 35) or the intervention group receiving probiotic supplements along with 400 IU of vitamin D (n = 35).1

The primary outcomes, focusing on the severity of the illness and cognitive function, were assessed using the Positive and Negative Syndrome Scale (PANSS) and the Montreal Cognitive Assessment (MoCA) tests, respectively. Secondary outcomes such as lipid profile, body mass index (BMI), gastrointestinal (GI) issues, serum C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) were also measured.1

A total of 69 patients successfully completed the study. In the group receiving probiotic-containing supplements, the MoCA score showed a notable increase of 1.96 units compared with the placebo group (p = 0.004).1

The proportion of participants achieving a MoCA score of ≥26 exhibited a significant rise in the intervention group (p = 0.031). Additionally, total cholesterol (TC) (p = 0.011), fasting blood sugar (FBS) (p = 0.009), and C-reactive protein (CRP) (p < 0.001) experienced significant reductions in the supplement group compared with the placebo group. Although the probiotic supplement led to a decrease of 2.82 units in PANSS score, the disparity between the study groups did not reach statistical significance (p = 0.247).1

According to the investigators, this study marks the first utilization of a combined supplement of probiotic and vitamin D—a formulation that is gaining popularity due to its increased accessibility for prescription compared with previous interventions. The study also represents the inaugural assessment of the impact of probiotic supplementation on MoCA score in individuals with schizophrenia.1

However, the investigators also noted several study limitations, including the absence of consideration for the vitamin D status of the study population and the lack of detailed information regarding the medications administered to participants in both study groups. They suggested that employing block randomization rather than simple randomization may prove beneficial in controlling for potential covariates such as medication regimens in future research endeavors.1

“Although the current randomized controlled trial revealed that probiotic supplementation along with vitamin D improves the cognitive function of schizophrenic patients,” the investigators concluded, “considering the limitations mentioned before, similar studies should be conducted to achieve a final decision.”

Read the full study in Neuropsychopharmacology Reports here.

According to the World Health Organization, approximately 24 million individuals worldwide are affected by schizophrenia at a rate of 1 in 222 individuals among adults. Individuals with schizophrenia are up to 3 times more likely to die prematurely compared with members of the general population.2 Here are some expert updates and discussions on the treatment of schizophrenia as seen in Psychiatric Times®:

Associations of the Gut Microbiome and Treatment Resistance in Schizophrenia

Developing Effective Treatment Strategies for Women With Schizophrenia

Constipation Conundrum With Clozapine

Medication Pipeline: Schizophrenia and PTSD

Stay up-to-date on news related to research on promising new interventions and developments in the treatment of schizophrenia, as well as a wide variety of other psychiatric disorders at

Note: This article was prepared with the assistance of ChatGPT.


1. Mohammadi A, Sadighi G, Astaneh AN, et al. Co-administration of probiotic and vitamin D significantly improves cognitive function in schizophrenic patients: a double-blinded randomized controlled trial. Neuropsychopharmacol Rep. 2024;00:1-10.

2. Schizophrenia. World Health Organization. January 10, 2022. Accessed April 12, 2024.

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