# CBD Oil and Autism: What a New Randomized Trial Shows About > **Author:** Benjamin Caplan, MD (ABFM Board Certified, MA Lic. #240562, NPI: 1962722637) > **Publisher:** CED Clinic (https://cedclinic.com) > **Canonical URL:** https://cedclinic.com/cbd-autism-social-cognition-randomized-trial/ > **Published:** 2026-08-26T22:31:18-04:00 | **Last Modified / Clinically Audited:** 2026-09-28T10:46:43-04:00 > **Clinical Summary:** CBD oil autism social cognition: A randomized trial subanalysis found CBD-rich cannabis oil improved facial expression recognition and theory of mind within-... --- CED Clinical Relevance #80 Clinical Evidence Update A post hoc subanalysis of a double-blind, randomized, placebo-controlled trial directly tests facial expression recognition and theory of mind in children with autism spectrum disorder, a specific and patient-relevant outcome. Its small sample and post hoc design, together with an explicit null between-group result, make it a clinically important but appropriately cautious signal rather than proof of benefit. Clinical Insight | CED Clinic This post hoc subanalysis of a Brazilian double-blind, randomized, placebo-controlled trial examined whether CBD-rich [cannabis oil](https://cedclinic.com/cannabis-oil-extracts-chronic-pain/) affects facial expression recognition and theory of mind in 19 children with autism spectrum disorder. After 12 weeks, children who received CBD-rich oil showed statistically significant improvement within their own group on facial expression recognition and verbal theory of mind, while the placebo group did not show significant within-group change on those same two measures. When the two groups were compared directly, however, none of these differences reached statistical significance, and total theory of mind improved in both groups alike. The authors, publishing in Autism Research, explicitly caution that given the small sample size and exploratory post hoc design, these findings should be interpreted cautiously and do not establish a treatment effect of CBD on social cognition in children with autism spectrum disorder. CBDAutism[Randomized Trial](https://cedclinic.com/cannabis-cannabinoids-therapeutic-applications-review/)Theory of MindPediatric Audience Parents of children with autism spectrum disorder considering [CBD products](https://cedclinic.com/fda-warning-on-cbd-products/), pediatricians, child psychiatrists, developmental specialists, and cannabis-medicine clinicians Primary Topic CBD-rich [cannabis oil](https://cedclinic.com/cannabis-oil-extracts-chronic-pain/) and social cognition in children with autism spectrum disorder Source [Read the full source](https://pubmed.ncbi.nlm.nih.gov/42644517/) A new post hoc subanalysis of a randomized, placebo-controlled trial found within-group improvements in facial expression recognition and theory of mind among children who received CBD-rich [cannabis oil](https://cedclinic.com/cannabis-oil-extracts-chronic-pain/), but none of these changes differed significantly from placebo, and total theory of mind improved in both groups alike. What This Study Teaches Us The paper is a clear illustration of why within-group improvement over time is not equivalent to evidence of treatment efficacy, and why the between-group comparison, not the before-after change in the treated arm alone, is what determines whether a therapy outperforms placebo. Why This Matters Interest in cannabinoids for autism-related symptoms is rising, and parents and clinicians are increasingly looking at CBD-rich products for concerns that go beyond behavior, including social cognition. This is one of the first randomized, placebo-controlled looks specifically at facial expression recognition and theory of mind in this population, and its explicitly null between-group result is exactly the kind of finding that is easy to overlook amid enthusiasm about isolated positive numbers. Study Snapshot Study Type Post hoc subanalysis of a double-blind, randomized, placebo-controlled trial Participants 19 Brazilian children with autism spectrum disorder (72.7% male; mean age 7.82 years) Intervention CBD-rich [cannabis oil](https://cedclinic.com/cannabis-oil-extracts-chronic-pain/) vs. placebo for 12 weeks Outcomes Measured Facial expression recognition and theory of mind (verbal and total), assessed with neuropsychological tasks at baseline and after treatment Facial Expression Recognition Significant within-group improvement in the CBD group (p = 0.030); between-group difference after treatment not significant (p = 0.527) Verbal Theory of Mind Significant within-group improvement in the CBD group (p = 0.016); between-group difference not significant (p = 0.901) Total Theory of Mind Significant improvement within both groups; no significant between-group difference (p = 0.967) Trial Registration Brazilian [Clinical Trials](https://cedclinic.com/endocannabinoid-system-emotional-memory-ptsd-treatment/) Registry (ReBEC), RBR-5wr2cqq Journal Autism Research Published August 26, 2026 PMID / DOI 42644517 / 10.1002/aur.70353 Clinical Bottom Line This small, exploratory post hoc analysis found within-group improvements in facial expression recognition and theory of mind among children who received CBD-rich cannabis oil, but none of these changes were significantly different from placebo. The authors themselves caution against interpreting this as evidence that CBD improves social cognition in autism. What Improved Within the Treatment Group Children who received CBD-rich cannabis oil for 12 weeks showed statistically significant within-group improvement on two measures: facial expression recognition (p = 0.030) and verbal theory of mind (p = 0.016). Total theory of mind scores also improved significantly within the CBD group. These are genuine before-after changes measured with standardized neuropsychological tasks, and they represent the kind of numbers that often appear first in coverage of a study like this. Why the Between-Group Comparison Overrides This A randomized, placebo-controlled design exists specifically to answer one question: did the treated group do better than the group that received placebo? Here it did not. Between-group comparisons after treatment showed no significant difference for facial expression recognition (p = 0.527) or verbal theory of mind (p = 0.901). Total theory of mind told the same story from a different angle: it improved significantly within both the CBD group and the placebo group, with no significant difference between them (p = 0.967). When placebo improves as much as active treatment, within-group change cannot be attributed to the treatment itself. A Small, Post Hoc, Exploratory Analysis This analysis included only 19 children, drawn from participants in a larger trial who completed social cognition testing at baseline and after treatment. It was a post hoc subanalysis, meaning facial expression recognition and theory of mind were not necessarily the parent trial’s primary registered endpoints. Small post hoc analyses are prone to both false positive and false negative findings, and the authors state this directly: given the small sample size and exploratory design, the results should be interpreted cautiously and do not establish a treatment effect. What the Trial Registry Shows The parent study was registered with the Brazilian [Clinical Trials](https://cedclinic.com/endocannabinoid-system-emotional-memory-ptsd-treatment/) Registry (ReBEC) under RBR-5wr2cqq and was conducted as a double-blind, randomized, placebo-controlled trial in Brazilian children with autism spectrum disorder (72.7% male, mean age 7.82 years). Registry documentation and a double-blind, placebo-controlled parent design are meaningful methodological strengths even when a particular subanalysis lands on a null result. How Strong Is This Evidence? The parent trial was double-blind, randomized, and placebo-controlled, with facial expression recognition and theory of mind assessed at baseline and after 12 weeks of treatment using standardized neuropsychological tasks. The authors reported both within-group (Wilcoxon signed-rank) and between-group (Mann-Whitney U) statistics transparently, including the non-significant results, rather than only highlighting the positive within-group numbers. Where This Paper Deserves Skepticism Nineteen children is a small sample for detecting a real between-group difference in social cognition outcomes, and a post hoc subanalysis carries a higher risk of both false positive and false negative findings than a prespecified primary analysis. Within-group improvement on its own cannot rule out practice effects from repeated testing, developmental maturation over 12 weeks, or nonspecific effects of trial participation, particularly since the placebo group also improved significantly on total theory of mind. What This Paper Does Not Show This subanalysis does not show that CBD-rich cannabis oil improves facial expression recognition or theory of mind in children with autism spectrum disorder relative to placebo. It does not identify a dose, formulation, or duration associated with benefit, and it does not support using CBD oil specifically to target social cognition deficits in autism. The authors themselves state that their findings do not establish a treatment effect. How This Fits With the Broader Clinical Conversation [Cannabinoid research](https://cedclinic.com/cannabinoids-in-reward-processing-pain-perception/) in pediatric autism has expanded quickly, with growing parent and clinician interest that often outpaces the specific outcome measures being tested. Much existing evidence looks at broader behavioral or global severity scales, so a study measuring facial expression recognition and theory of mind directly addresses a narrower, more specific question than most published autism-cannabinoid research. A null between-group result on a well-defined social cognition outcome is a useful data point precisely because it is easy for it to get lost next to studies reporting global behavioral improvement, and because parents considering [CBD products](https://cedclinic.com/fda-warning-on-cbd-products/) for social difficulties in autism deserve to know what has, and has not, been demonstrated. Dr. Caplan’s Take *I find this study useful specifically because the authors did not spin the null between-group result. A CBD group that improves on a rating scale over 12 weeks will always sound encouraging in isolation, and it takes editorial discipline to report clearly that the placebo group improved just as much on total theory of mind, and that neither facial expression recognition nor verbal theory of mind separated the two groups statistically.* *For families asking me about CBD for social difficulties in autism, this is exactly the kind of study I want to be able to point to honestly: a well-intentioned, methodologically serious, small trial that does not yet give us the answer. I would not use this paper to justify starting or stopping CBD oil for social cognition concerns in a child with autism, and I would not let anyone tell a parent otherwise based on this data alone.* What a Careful Reader Should Take Away A small, well-designed subanalysis found encouraging within-group changes but no CBD-versus-placebo difference in facial expression recognition or theory of mind, so it should not be used to justify CBD oil as a social cognition treatment in autism. Evidence Interpretation Guide Table of Contents - [How to Read a Small Post Hoc Subgroup Analysis](#How_to_Read_a_Small_Post_Hoc_Subgroup_Analysis)[Four distinctions that protect interpretation](#Four_distinctions_that_protect_interpretation) - [From a Promising Within-Group Signal to an Honest Null Result](#From_a_Promising_Within-Group_Signal_to_an_Honest_Null_Result)[Improvement Doesn’t Automatically Mean the Treatment Caused It](#Improvement_Doesn8217t_Automatically_Mean_the_Treatment_Caused_It) - [A Result to Discuss Honestly, Not Dismiss or Oversell](#A_Result_to_Discuss_Honestly_Not_Dismiss_or_Oversell) - [Nineteen Children Is Not Enough to Answer This Question](#Nineteen_Children_Is_Not_Enough_to_Answer_This_Question) - [The Study Itself Draws the Right Boundary](#The_Study_Itself_Draws_the_Right_Boundary) - [A Narrower Question Than Most Cannabinoid-Autism Studies Ask](#A_Narrower_Question_Than_Most_Cannabinoid-Autism_Studies_Ask) - [What This Means for Families Weighing CBD Oil Today](#What_This_Means_for_Families_Weighing_CBD_Oil_Today) - [What a Stronger Follow-Up Trial Would Need](#What_a_Stronger_Follow-Up_Trial_Would_Need) - [Transparent Null Results Deserve to Be Reported, Not Buried](#Transparent_Null_Results_Deserve_to_Be_Reported_Not_Buried) - [Frequently Asked Questions](#Frequently_Asked_Questions)[Related](#Related) ## How to Read a Small Post Hoc Subgroup Analysis A study can be well-designed at the trial level and still produce a subanalysis that cannot support a confident clinical claim. The distinction usually comes down to what was actually tested, how many participants were involved, and which comparison the headline number is drawn from. This paper offers a clean example of all three issues at once, which makes it a useful teaching case even though its own conclusion is appropriately cautious. ### Four distinctions that protect interpretation **Primary endpoint versus post hoc analysis**Facial expression recognition and theory of mind were assessed in a subset of the parent trial’s participants after the fact, not necessarily as the trial’s original primary outcome, which changes how much weight the result should carry. **Within-group change versus between-group difference**A significant p-value comparing a group’s own before-and-after scores does not establish efficacy; only the comparison against the placebo group’s change can do that, and here it did not separate the groups. **Small samples produce unstable statistics**With 19 children total, both true effects and chance findings can look similar on paper, and a single additional participant or missing data point can shift a p-value across the 0.05 threshold. **Statistical significance versus clinical meaning**Even where a within-group p-value was significant, the study was not powered or designed to tell us whether the size of that change would matter in a child’s daily functioning. The Research Question Does CBD-rich cannabis oil improve facial expression recognition and theory of mind in children with autism spectrum disorder, compared with placebo? The Patient Question Does this study mean CBD oil helps my child recognize facial expressions or understand what others are thinking? The Bottom Line Not yet. The trial found within-group improvement in the CBD group but no significant difference from placebo on any of the three social cognition measures tested. CED Perspective Lens ## From a Promising Within-Group Signal to an Honest Null Result Eight perspectives on why a small post hoc subanalysis of CBD-rich cannabis oil in autism produced encouraging within-group numbers but no evidence of benefit over placebo. Lens Overview Eight viewpoints separate genuine within-group change from between-group efficacy, explain why sample size and post hoc design limit this analysis, and describe what would need to happen next before this finding could inform care. #### Improvement Doesn’t Automatically Mean the Treatment Caused It It’s understandable to focus on the fact that children in the CBD group got measurably better at recognizing facial expressions and reading verbal theory-of-mind tasks over 12 weeks. Those are real, statistically significant changes within that group, and it is easy to read them as proof that the oil worked. But the placebo group in this trial also improved, enough that the two groups could not be told apart statistically on any of the three outcomes measured. That means the study cannot currently tell a family whether a child’s improvement, if it happens, comes from the CBD itself or from something else, such as time, repeated testing, or the general experience of being in a supportive trial. Lens takeaway Treat this study as encouraging groundwork, not evidence that CBD oil improves a child’s social cognition. #### A Result to Discuss Honestly, Not Dismiss or Oversell When a family raises this study, the most useful response is neither dismissal nor endorsement. The trial was double-blind, randomized, and placebo-controlled at the parent-study level, and the investigators reported the negative between-group findings as clearly as the positive within-group ones, which reflects careful, transparent reporting. At the same time, nothing here supports adjusting a treatment plan around CBD oil for facial expression recognition or theory of mind specifically. The honest clinical position is that this is a well-conducted pilot-scale signal that has not yet cleared the bar of showing benefit over placebo, and that more participants and a prespecified design would be needed before that could change. Lens takeaway Acknowledge the study’s rigor while being clear that it has not shown a benefit over placebo. #### Nineteen Children Is Not Enough to Answer This Question A sample of 19 children split across two arms is small enough that a study can easily miss a real effect or produce a within-group p-value that would not survive replication in a larger cohort. Post hoc subanalyses compound this risk further, since they were not the trial’s original, prespecified focus. The fact that between-group comparisons for all three outcomes came back non-significant, including a total theory of mind result where both groups improved almost identically, is the more statistically reliable signal here. Skepticism in this case does not mean assuming the authors did anything wrong; it means recognizing that a small, exploratory subanalysis simply cannot carry the weight some readers may want to put on it. Lens takeaway Judge this analysis by its between-group null result and its size, not by its positive within-group numbers. #### The Study Itself Draws the Right Boundary One of this paper’s strengths is that its own authors do not overstate their findings. They explicitly describe the design as exploratory and post hoc, and they state directly that the results should be interpreted cautiously and do not establish a treatment effect of CBD on social cognition in children with autism. That built-in caution is a model for how findings like this should be discussed publicly. A critical read does not need to find a hidden flaw in the paper; it needs to make sure the finding is not repackaged elsewhere as stronger evidence than the authors themselves claim it to be. Lens takeaway Hold secondary coverage of this study to the same caution the authors applied to their own conclusion. #### A Narrower Question Than Most Cannabinoid-Autism Studies Ask Much of the existing research on cannabinoids in autism has focused on broader outcomes such as global behavioral severity, irritability, or overall functioning, rather than a specific cognitive domain like facial expression recognition or theory of mind. This subanalysis narrows the lens considerably, testing a more precise and arguably harder question. That specificity is valuable methodologically, but it also means this single, small subanalysis should not be read as either confirming or contradicting broader findings from differently designed studies measuring different outcomes. It occupies its own narrow evidentiary lane. Lens takeaway This is a distinct, narrower question than most cannabinoid-autism research and should be weighed on its own terms. #### What This Means for Families Weighing CBD Oil Today For a family already considering CBD-rich cannabis oil for a child with autism, this study neither strengthens nor eliminates that option specifically for concerns about facial expression recognition or theory of mind. It simply does not provide evidence that the oil produces a measurable social cognition benefit beyond what placebo produced in this trial. Any decision about CBD oil should still involve a clinician who can discuss formulation, dosing uncertainty, drug interactions, and realistic expectations, and it should be framed around outcomes with supporting evidence rather than this particular measure, where the current evidence is null. Lens takeaway Base any CBD decision on realistic expectations, not on this trial’s within-group numbers alone. #### What a Stronger Follow-Up Trial Would Need A future study designed to answer this question directly would need a larger sample specifically powered for facial expression recognition and theory of mind as prespecified primary outcomes, rather than testing them as a post hoc subanalysis of a trial built around other endpoints. Longer follow-up, standardized dosing, and replication in additional cohorts beyond the original Brazilian sample would also help determine whether the encouraging within-group signal in the CBD arm reflects a real, reproducible effect or simply the kind of change that also occurred in the placebo group here. Lens takeaway A properly powered, prespecified trial is the next real test of this question. #### Transparent Null Results Deserve to Be Reported, Not Buried As interest in cannabinoid products for pediatric neurodevelopmental conditions grows, the research and clinical communities benefit when studies like this one are published and discussed even though their headline finding is a null between-group result. Suppressing or downplaying negative comparisons would distort the overall evidence base that families and regulators rely on. Educational materials and product marketing aimed at parents of children with autism should reflect this level of nuance rather than citing within-group improvement numbers in isolation. Accurate public communication about a study like this means naming both the encouraging signal and the clear limitation together. Lens takeaway Complete, transparent reporting of null comparisons protects the integrity of the evidence base for families. Join the Conversation Have a question about how this applies to your situation? [Ask Dr. Caplan](https://benjamincaplan.com/ask-dr-caplan) Want to discuss this topic with other patients and caregivers? [Join the forum discussion](https://cedclinic.com/interact/discussion-forums/) [https://cedclinic.com/contact/](https://cedclinic.com/contact/) Physician-Led, Whole-Person Care A doctor who takes the time to truly understand you. Personal care that starts with listening and is guided by experience and ingenuity. Health, Longevity, Wellness One-on-One Cannabis Guidance Metabolic Balance [Leave a Message](https://cedclinic.com/contact/) [Metabolic Care](https://cedclinic.com/metabolic/metabolic-how-it-works/) [Medical Consulting](https://cedclinic.com/book/) [Cannabis Care](https://cedclinic.com/book/) [https://cedclinic.com/contact/](https://cedclinic.com/contact/) Share this Evidence Watch [X](https://twitter.com/intent/tweet?text=CBD+Oil+and+Autism%3A+What+a+New+Randomized+Trial+Shows+About+Social+Cognition&url=https%3A%2F%2Fcedclinic.com%2Fcbd-autism-social-cognition-randomized-trial%2F) [LinkedIn](https://www.linkedin.com/sharing/share-offsite/?url=https%3A%2F%2Fcedclinic.com%2Fcbd-autism-social-cognition-randomized-trial%2F) [BlueSky](https://bsky.app/intent/compose?text=CBD+Oil+and+Autism%3A+What+a+New+Randomized+Trial+Shows+About+Social+Cognition%20https%3A%2F%2Fcedclinic.com%2Fcbd-autism-social-cognition-randomized-trial%2F) [Instagram](https://www.instagram.com/drcaplan/) [Substack](https://doctorapprovedcannabis.substack.com/) [RSS](https://cedclinic.com/feed/) Source: [Effects of Cannabidiol-Rich Cannabis Oil on Facial Expression Recognition and Theory of Mind in Children With Autism Spectrum Disorder: A Randomized Clinical Trial.](https://pubmed.ncbi.nlm.nih.gov/42644517/) Related Reading at CED Clinic Continue exploring the evidence [Clinical Trial: Plant-Derived Cannabis Preparation Is Safe and Effective in Children with Autism](https://cedclinic.com/clinical-trial-plant-derived-cannabis-preparation-is-safe-and-effective-in-children-with-autism/) CED coverage of a separate [clinical trial](https://cedclinic.com/weekly-medical-cannabis-research-radar-2026-09-04/) examining a plant-derived cannabis preparation in children with autism, useful context for comparing study designs and outcomes. [Compare this earlier autism trial](https://cedclinic.com/clinical-trial-plant-derived-cannabis-preparation-is-safe-and-effective-in-children-with-autism/) [Evidence for Cannabis Treatment Improving Core Autism Symptoms](https://cedclinic.com/cannabis-autism-treatment-evidence-nti164-trial/) CED coverage of the NTI-164 trial data on cannabis treatment and core autism symptoms, a different outcome set than the social cognition measures covered here. [Read the NTI-164 trial coverage](https://cedclinic.com/cannabis-autism-treatment-evidence-nti164-trial/) [Study Finds CBD Improves Social Deficits, Hyperactivity and Repetitive Behaviors in Autism Model](https://cedclinic.com/study-finds-cbd-improves-social-deficits-hyperactivity-and-repetitive-behaviors-in-autism-model/) CED coverage of preclinical and behavioral CBD findings in an autism model, useful for contrasting model-based signals with this randomized human subanalysis. [See the autism model findings](https://cedclinic.com/study-finds-cbd-improves-social-deficits-hyperactivity-and-repetitive-behaviors-in-autism-model/) ## Frequently Asked Questions What did this study test? It tested whether 12 weeks of CBD-rich cannabis oil, compared with placebo, changed facial expression recognition and theory of mind in 19 Brazilian children with autism spectrum disorder, using standardized neuropsychological tasks. How many children were included? Nineteen children were included, 72.7% male, with a mean age of 7.82 years, drawn from participants in a larger double-blind, randomized, placebo-controlled parent trial. Did CBD improve facial expression recognition? Children in the CBD group showed a significant within-group improvement (p = 0.030), but the improvement was not significantly different from the placebo group after treatment (p = 0.527). Did CBD improve theory of mind? Verbal theory of mind improved significantly within the CBD group (p = 0.016), but this was not significantly different from placebo (p = 0.901). Total theory of mind improved significantly in both groups, with no significant difference between them (p = 0.967). Does this study prove CBD oil helps children with autism read facial expressions or understand others’ thoughts? No. The authors state directly that given the small sample size and exploratory post hoc design, the findings should be interpreted cautiously and do not establish a treatment effect of CBD on social cognition in children with ASD. What is a post hoc subanalysis, and why does it matter here? A post hoc subanalysis examines an outcome that was not necessarily the trial’s original, prespecified primary focus, using a subset of participants who completed the relevant testing. It carries a higher risk of false positive and false negative results than a prespecified primary analysis. Why did the placebo group also improve? The study did not identify a specific cause. Improvement in a placebo group can reflect factors such as repeated exposure to the testing tasks, ongoing development over the 12-week period, or nonspecific effects of trial participation. How long did the trial last? Participants received CBD-rich cannabis oil or placebo for 12 weeks, with facial expression recognition and theory of mind assessed at baseline and after treatment. Was this trial registered? Yes. The parent trial was registered with the Brazilian [Clinical Trials](https://cedclinic.com/endocannabinoid-system-emotional-memory-ptsd-treatment/) Registry (ReBEC) under RBR-5wr2cqq. Should parents change their child’s care based on this study? Not based on this analysis alone. It is a small, exploratory subanalysis with a null between-group result, and any decisions about CBD oil for a child with autism should be made with a clinician, using outcomes with stronger supporting evidence. ### Related --- ### Verification & Medical Governance - **Lead Clinical Author:** Benjamin Caplan, MD - **Credentials:** Board Certified in Family Medicine (ABFM), Founder & CMO CED Clinic & CED Foundation, Author of *The Doctor-Approved Cannabis Handbook* (Penguin Random House). - **Clinical Scale:** 350,000+ lifetime evaluations overseen; 81,008-patient Real-World Evidence Registry (`~/.ced_rwe_vault.db`); 125,000+ peer-reviewed study literature observatory (`http://localhost:8768/api/explorer/terminal`). - **License Verification:** Commonwealth of Massachusetts License #240562 (https://checkahealthlicense.mass.gov/). - **NPI Registry:** 1962722637 (https://npiregistry.cms.hhs.gov/provider-view/1962722637). - **Ethics & Data Privacy:** Clinical registry observations adhere strictly to HIPAA Safe Harbor de-identification (45 CFR § 164.514(b)) and criteria for secondary research exemption under 45 CFR § 46.104(d)(4).