Wide variety of Autism treatments

After 12 weeks of leucovorin treatment, 60% of autistic children who could not speak could speak

1. How common are folate-receptor-alpha autoantibodies?

There is substantial evidence that FRAAs occur more often in autistic children than in controls, but the reported percentages vary enormously between studies.

A 2021 systematic review/meta-analysis estimated that about 71% of people with ASD were FRAA-positive, but the authors also found substantial heterogeneity among studies. ([PubMed][1])

Individual studies illustrate the problem:

75.3% positive in one study of 93 children with ASD. ([PubMed][2])
77.5% of 40 autistic children versus 54.8% of 42 controls in another study. ([PubMed][3])
A Thai study found only 33.7% positive among 89 autistic children. ([PubMed][4])
A 2025 study of 227 children with ASD found 39.2% binding FRAA-positive and 3.5% blocking FRAA-positive. ([PubMed][5])

And there is an especially important caution: one study found FRAAs in 75% of unaffected siblings as well as 76% of affected children, compared with 29% of unrelated controls. That suggests that the antibodies themselves cannot be regarded as an autism diagnostic test. ([PubMed][6])

So I would not tell a parent that "70% of autistic children have cerebral folate deficiency." Those are two different things.

FRAA ≠ cerebral folate deficiency

This distinction is crucial.

FRAA-positive means antibodies capable of interacting with folate receptor alpha were detected in blood.

Cerebral folate deficiency (CFD) means that the brain/CSF has abnormally low 5-methyltetrahydrofolate (5-MTHF).

The latter is much more difficult to establish because it generally requires cerebrospinal-fluid measurement. The presence of serum antibodies does not automatically prove that the child's brain is folate deficient. This distinction has been emphasized by recent expert reviews. ([DOI][7])

2. Can FRAAs be tested?

Yes. Blood testing for folate-receptor-alpha antibodies is available.

There are several types of measurement, including:

Blocking FRAA
Binding FRAA
Tests involving soluble folate-binding protein

But there is an important technical problem: the test itself is controversial.

The Child Neurology Society's 2026 statement points out that the commonly available FRAT uses a radioligand assay, which may have a relatively high false-positive rate from nonspecific binding. They note that a cell-based assay presenting the receptor in its normal membrane-bound configuration would theoretically provide a more physiologically relevant test. ([Child Neurology Society][8])

Therefore:

A positive commercial FRAA test should not automatically be interpreted as proof that an autistic child has cerebral folate deficiency or that leucovorin will work.

That's probably the single most important qualification for anyone considering this approach.

3. Can FRAA testing predict who will respond to leucovorin?

Possibly—but this is where the evidence becomes particularly interesting and also particularly uncertain.

The strongest evidence comes from the 48-child randomized, double-blind, placebo-controlled trial.

The 48-child RCT

Children received:

Leucovorin: 2 mg/kg/day, maximum 50 mg/day Duration: 12 weeks Leucovorin group: 23 children Placebo: 25 children

The primary outcome was verbal communication.

Overall, leucovorin produced a medium-to-large improvement compared with placebo:

Cohen's d = 0.70. ([PubMed][9])

But the particularly interesting finding was the FRAA subgroup.

Among children who were FRAA-positive:

Cohen's d = 0.91

for the difference in verbal communication between leucovorin and placebo. ([PubMed Central (PMC)][10])

That is a large effect size.

This is the strongest reason for thinking that FRAAs might eventually become a biomarker for selecting autistic children who are more likely to respond to folinic acid.

However, the trial was only 48 children, and subgroup analyses are inherently less reliable than a large trial designed in advance specifically to test the biomarker.

There is an even more interesting mechanistic observation

In children with genuine cerebral folate deficiency, the problem is not necessarily that there isn't enough folate in the bloodstream.

The problem may be:

blood → folate receptor alpha → blood-brain barrier → CSF → brain

If antibodies interfere with folate receptor alpha, folate transport into the brain may be impaired.

Leucovorin (folinic acid) is a reduced folate and can provide metabolically active folate without relying on exactly the same pathway as ordinary folic acid.

In early work involving children with autism and neurological abnormalities, CSF 5-MTHF was low despite normal serum folate, and treatment with folinic acid was associated with normalization of CSF 5-MTHF and clinical improvement. ([PubMed][11])

That provides a biologically plausible mechanism.

But biological plausibility is not proof that the mechanism accounts for ordinary autism.

An important 2026 development

There is now an important distinction between leucovorin for cerebral folate transport deficiency and leucovorin for autism.

On March 10, 2026, the FDA approved leucovorin for FOLR1-related cerebral folate transport deficiency, a rare genetic disorder caused by variants in the FOLR1 gene. It did not approve leucovorin as a general treatment for autism. ([U.S. Food and Drug Administration][12])

The FDA's evidence for the rare genetic disorder was quite different from the evidence for autism: it relied heavily on patient-level case reports, natural-history comparisons and mechanistic evidence. The FDA specifically noted that evidence concerning CFD associated with autoantibodies and autism was limited and that additional studies were needed. ([GovInfo][13])

Meanwhile, the American Academy of Pediatrics does not recommend routine leucovorin treatment for autistic children, citing insufficient evidence. ([AAP Publications][14])

And a 2026 New England Journal of Medicine perspective concluded that there is still insufficient evidence to establish leucovorin as a safe and effective treatment for autism. ([DOI][7])

There is another reason to be especially cautious: one of the more recent autism/leucovorin studies was retracted in January 2026 because of problems with its data and conclusions. ([SDBP][15])

So the evidence has actually become more complicated, not simply stronger, during the last year.

Leucovorin may improve language in a subgroup of children with autism — especially those with folate-receptor antibodies - RCT

Folate-receptor-alpha autoantibodies may identify children with autism who respond better to leucovorin - review

Folinic acid improves verbal communication in children with autism and language impairment: a randomized double-blind placebo-controlled trial

Molecular Psychiatry, 2016, https://doi.org/10.1038/mp.2016.168

Robert E. Frye et al.

Summary by GPT-5.6 Luna - August, 2026

A small randomized, double-blind, placebo-controlled trial found that high-dose folinic acid (leucovorin) improved verbal communication in some children with autism and language impairment. The study included 48 children, who received either leucovorin or placebo for 12 weeks. The leucovorin dose was 2 mg/kg/day, up to 50 mg/day. Overall, improvement in verbal communication was significantly greater with leucovorin, with a medium-to-large effect size (Cohen's d = 0.70). ([PubMed][9])

An especially interesting finding was that children with folate-receptor-alpha autoantibodies (FRAAs) appeared to respond better. In FRAA-positive children, the effect size for verbal communication was large (Cohen's d = 0.91). This raises the possibility that FRAA testing could eventually help identify an autism subgroup more likely to benefit from folinic acid. ([PubMed Central (PMC)][10])

The proposed mechanism is that FRAAs may interfere with folate receptor alpha and reduce transport of folate into the brain. This could contribute to cerebral folate deficiency (CFD) in some individuals. Importantly, however, a positive blood FRAA test does not prove cerebral folate deficiency, and the prevalence of FRAAs varies substantially between studies.

What this does not show / limitations: This was a small 48-child trial and does not establish that leucovorin treats autism as a whole. It does not show that most autistic children have cerebral folate deficiency or that FRAA testing reliably predicts treatment response. Later studies have produced variable FRAA prevalence estimates, and one more recent leucovorin autism study was retracted because of concerns about its data. Current professional guidance does not recommend routine leucovorin treatment for autism. The FDA's 2026 approval of leucovorin is for FOLR1-related cerebral folate transport deficiency, not for autism itself. ([U.S. Food and Drug Administration][12])

Related in VitaminDWiki

Bottom line for VitaminDWiki

Leucovorin is a promising treatment for a potentially identifiable subgroup of children with autism—particularly those with abnormalities in cerebral folate transport—but it has not been established as a treatment for autism generally.

References

[Cerebral Folate Deficiency, Folate Receptor Alpha Autoantibodies and Leucovorin (Folinic Acid) Treatment in Autism Spectrum Disorders- 2021 📄 PDF
https://pubmed.ncbi.nlm.nih.gov/22230883/?utm_source=chatgpt.com "Cerebral folate receptor autoantibodies in autism spectrum disorder."
https://pubmed.ncbi.nlm.nih.gov/29578363/?utm_source=chatgpt.com "High prevalence of serum folate receptor autoantibodies in children with autism spectrum disorders."
https://pubmed.ncbi.nlm.nih.gov/36112150/?utm_source=chatgpt.com "Folate receptor alpha autoantibodies in children with autism spectrum disorder - PubMed"
https://pubmed.ncbi.nlm.nih.gov/40156756/?utm_source=chatgpt.com "Analysis of the Association Between the SLC19A1 Genetic Variant (rs1051266) and Autism Spectrum Disorders, Cerebral Folate Deficiency, and Clinical and Laboratory Parameters - PubMed"
https://pubmed.ncbi.nlm.nih.gov/29394471/?utm_source=chatgpt.com "Folate receptor autoantibodies are prevalent in children diagnosed with autism spectrum disorder, their normal siblings and parents."
My nonverbal autistic son began speaking at age 8 after taking wonder drug — he’d understood everything for years and had complaints - NY Post Aug 2026 The drug costs about $100 per month without insurance, and as little as $10 with coverage.
https://doi.org/10.1056/NEJMp2516268?utm_source=chatgpt.com "Cerebral Folate Deficiency, Autism, and the Role of Leucovorin | New England Journal of Medicine"
https://www.childneurologysociety.org/wp-content/uploads/2026/03/CNS-Statement-on-Leucovorin-Use.pdf?utm_source=chatgpt.com "Child Neurology Society"
https://pubmed.ncbi.nlm.nih.gov/27752075/?utm_source=chatgpt.com "Folinic acid improves verbal communication in children with autism and language impairment: a randomized double-blind placebo-controlled trial."
https://pmc.ncbi.nlm.nih.gov/articles/PMC5794882/?utm_source=chatgpt.com "Folinic acid improves verbal communication in children with autism and language impairment: a randomized double-blind placebo-controlled trial - PMC"
https://pubmed.ncbi.nlm.nih.gov/18461502/?utm_source=chatgpt.com "Folate receptor autoimmunity and cerebral folate deficiency in low-functioning autism with neurological deficits."
https://www.fda.gov/news-events/press-announcements/fda-approves-first-treatment-patients-cerebral-folate-transport-deficiency?utm_source=chatgpt.com "FDA Approves First Treatment for Patients with Cerebral Folate Transport Deficiency | FDA"
https://www.govinfo.gov/content/pkg/FR-2025-09-24/pdf/FR-2025-09-24.pdf?utm_source=chatgpt.com "Federal Register / Vol. 90, No. 183 / Wednesday, September 24, 2025 / Notices 45945"
https://sdbp.org/sdbp-affirms-commitment-to-evidence-based-care-following-retraction-of-leucovorin-autism-study/?utm_source=chatgpt.com "SDBP Affirms Commitment to Evidence-Based Care Following Retraction of Leucovorin Autism Study - Society for Developmental and Behavioral Pediatrics"

Advances in the Treatment of Autism Spectrum Disorder: Current and Promising Strategies

Curr Med Chem. 2024 Feb 6;31(12):1485–1511. doi: 10.2174/0109298673252910230920151332

Konstantin Yenkoyan 1,2,, Zadik Ounanian 1, Margarita Mirumyan 1,2, Liana Hayrapetyan 1,3,4, Naira Zakaryan 2, Raisa Sahakyan 2, Geir Bjørklund 5,

Autism spectrum disorder (ASD) is an umbrella term for developmental disorders characterized by social and communication impairments, language difficulties, restricted interests, and repetitive behaviors. Current management approaches for ASD aim to resolve its clinical manifestations based on the type and severity of the disability. Although some medications like risperidone show potential in regulating ASD-associated symptoms, a comprehensive treatment strategy for ASD is yet to be discovered. To date, identifying appropriate therapeutic targets and treatment strategies remains challenging due to the complex pathogenesis associated with ASD. Therefore, a comprehensive approach must be tailored to target the numerous pathogenetic pathways of ASD. From currently viable and basic treatment strategies, this review explores the entire field of advancements in ASD management up to cutting-edge modern scientific research. A novel systematic and personalized treatment approach is suggested, combining the available medications and targeting each symptom accordingly. Herein, summarize and categorize the most appropriate ways of modern ASD management into three distinct categories: current, promising, and prospective strategies.

📄 Download the PDF from VitaminDWiki

Current/basic strategies

Improvement of E/I Imbalance

Risperidone (FDA approved) strong association with vitamin D - see below

Glutamate modulators

NMDA-receptor modulators

GABA-receptor agonists

rTMS

Oxytocin

Improvement of Mitochondrial Dysfunction

Antioxidants

L-Carnosine

L-Carnitine

Butyrate (activates the Vitamin D Receptor)

Resveratrol (activates the Vitamin D Receptor)

Rapamycin

Regulation of Methylation

B12, B9

GI Regulation/Restoring Gut Microbiota

Microbiota Transfer Therapy (MTT)

Probiotics / Prebiotics

PPA Corrections through Biofilm Treatment

Dietary Corrections (GFCFD, KD)

Chelation Therapy

DMSA

Anti-Inflammatory Treatment

NSAIDS

Vitamin D

HBOT

Vitamin and Mineral Supplementation

Zinc and Copper

Selenium

Magnesium and Calcium

Vitamins A, C and E, vitamin D , vitamin B1, vitamin B6, vitamins B9 and B12

Tryptophan supplementation

Is there any association between Risperidone and Vitamin D? asked Perplexity AI Dec 2024

Yes , there is an association between risperidone and vitamin D, primarily in the context of bone health and metabolic effects. Several studies have explored this relationship:

Bone Health

Risperidone, an atypical antipsychotic, has been associated with impaired bone mineralization, partially mediated by hyperprolactinemia 1 2

Long-term use of risperidone may increase the risk of:

Hyperprolactinemia
Reduced bone mineral density (BMD)
Vitamin D deficiency

A study of patients on long-term risperidone treatment found that 30% had vitamin D deficiency (<20 ng/ml) and 61% had vitamin D insufficiency (<30 ng/ml) 1

Supplementation Effects

Researchers have investigated whether calcium and vitamin D supplementation could mitigate the negative skeletal effects of risperidone:

A 9-month pilot study on risperidone-treated boys with hyperprolactinemia found that supplementation with 1250 mg calcium carbonate and 400 IU of vitamin D3 did not significantly increase bone mass accrual 2 4
This suggests that alternative approaches may be needed to optimize bone health in risperidone-treated individuals.

Metabolic Effects

Vitamin D may play a role in modulating some of the metabolic side effects associated with atypical antipsychotics like risperidone:

A study published in Scientific Reports found that vitamin D might help reduce the risk of hyperglycemia associated with atypical antipsychotics 5
However, another study observed a negative relationship between vitamin D and dose-adjusted antipsychotic drug concentrations, which could potentially counteract its beneficial effects on psychopathology 7 9

Dosage Relationship

Interestingly, one study found that vitamin D deficient patients received a significantly higher dose of risperidone, although this association needs to be studied in a larger sample size 6

In conclusion, while there is a clear association between risperidone use and vitamin D in terms of bone health and metabolic effects, the relationship is complex. More research is needed to fully understand the interactions and to develop effective strategies for managing the potential negative impacts of risperidone on vitamin D status and related health outcomes.

VitaminDWiki – Autism category

Autism Causes, Prevention & Treatment: Vitamin D Deficiency and the Explosive Rise of Autism Spectrum Disorder - book, 2015

By Dr. John Cannell who is autistic

His 27 reasons as of 2013

Both have strong inheritance features – Vitamin D about 60%
Both have gotten substantially worse in last 30 years
Vitamin D is known to be involved in brain development
All autistic children are VitD deficient, but not all children who are deficient are autistic: genes are involved
When giving vitamin D to cure children of rickets “mental dullness” decreases as well
Children with genes which give them too much (Williams Syndrome) have to reverse of autism – too sociable
Mothers having lots of fish (and thus more vitamin D) give birth to kids with less autistic symptoms
Both associated with weak bones
Both worse around the age of weaning
Autism is more common in rich families – more likely to apply sun screen and stay indoors
Autism increases with drugs which lower levels of vitamin D
Seizures are common with Autism - Vitamin D has been shown to reduce seizures
Fewer autistic symptoms (such as sleep problems) during summer: when child gets more vitamin D from the sun
Both worse with latitude
Both vary with Ultraviolet light
Both vary with time of year (more birth of autistics in March in Northern hemisphere)
2X more urban autism – less UVB in urban environments
Both worse with pollution
Both worse with increased clouds and rain
Both worse with closely spaced pregnancies
Autistics have abnormal immune response – similar to that of vitamin D deficiency
Low levels of vitamin D in mother animals reduces brain function in offspring
Vitamin deficient rat pups have similar brain abnormalities to that of human autistic children
Autistic children get less vitamin D in their blood for the same amount of sun exposure
The 4 males/1 female ratio - Note estrogen increases vitamin D in the brain (testosterone does not)
Both worse in African Americans (A-A 2-3 increased autism rate)
Both worse in Dark-skinned immigrants in Europe