The Claim

In adults with chronic schizophrenia receiving stable risperidone therapy, daily supplementation with 1 mg of vitamin B12 or 1 mg of folic acid for eight weeks significantly reduces the severity of negative symptoms as measured by the Scale for the Assessment of Negative Symptoms (SANS), with mean reductions of 19.4 to 26.5 points and large effect sizes (Cohen’s d = 0.80–0.95), while placebo shows no significant change.

Source: Effects of Vitamin B12 and Folic Acid Supplementation on Negative Symptoms as the Primary Outcome and Positive and Cognitive Symptoms as Secondary Outcomes in Schizophrenia: A Randomized Controlled Trial

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
82score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Cause and effect
1 study reviewed
In plain English

In adults with chronic schizophrenia taking stable risperidone, daily supplements of 1 mg vitamin B12 or 1 mg folic acid for eight weeks reduce negative symptoms by 19.4 to 26.5 points on the SANS scale, with large effect sizes, while placebo does not produce a significant change.

See the scientific wording

In adults with chronic schizophrenia receiving stable risperidone therapy, daily supplementation with 1 mg of vitamin B12 or 1 mg of folic acid for eight weeks significantly reduces the severity of negative symptoms, as measured by the Scale for the Assessment of Negative Symptoms (SANS), with mean reductions of 19.4 to 26.5 points, corresponding to large effect sizes (Cohen’s d = 0.80–0.95), while placebo shows no significant change.

Why this might work

Taking vitamin B12 and folic acid raises levels of these vitamins in the blood, which allows the body to convert homocysteine into methionine more efficiently. Methionine is used to make a molecule called SAMe, which adds methyl groups to DNA and neurotransmitters in the prefrontal cortex. This methylation turns on genes that help neurons communicate properly and balances dopamine signaling, which reduces emotional flatness and lack of speech.

Supported mechanismbased on 1 study

What the research says

1 study

  1. Study: Effects of Vitamin B12 and Folic Acid Supplementation on Negative Symptoms as the Primary Outcome and Positive and Cognitive Symptoms as Secondary Outcomes in Schizophrenia: A Randomized Controlled Trial

    For people with long-term schizophrenia who are already on antipsychotic medicine, taking a daily B12 or folic acid pill for eight weeks made their emotional numbness and lack of speech much better—much more than a sugar pill did.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.