Updated on March 23, 2023
For parents of autistic children, there are few symptoms that can cause as much day-to-day concern as stimming. Stimming—which is more formally discussed in scientific circles as self-stimulation or stereotypic, repetitive behavior—can be frustrating and concerning for parents who find themselves unable to get through to a child who is rocking, flapping, spinning, or repeating the same sets of words, over and over. Many parents worry that stimming behaviors set their child apart from their peers, who often view stereotypic, repetitive behaviors as “weird,” making it even harder for an autistic child to build strong social relationships.
In clinical settings, stimming is typically addressed with pharmacological drugs, behavioral modification therapy, or a combination of the two. However, because the efficacy of these interventions can vary significantly depending on the child, there is increasing interest within the research and clinical communities in nutritional supplements for addressing stimming. So far, multiple supplements have shown promise in animal models, several of which have also gained preliminary clinical support. Some of these supplements include Korean Red Ginseng, vitamin D, omega-3 fatty acids, and sulforaphane. Together, the similarities between these candidates suggest that supplements with properties that support the body’s natural inflammatory response, including curcumin and quercetin, present the best prospects for future laboratory and clinical research.
One of the ways researchers model stimming in vivo is by administering valproic acid to rats. Administration of valproic acid induces stereotypic, repetitive behaviors that closely parallel stimming behavior in autistic children while also triggering several other autism-related symptoms, such as problems with social interaction and motor activity. In one recent study, researchers used valproic acid-exposed rat models to suggest that Korean Red Ginseng supplements might have therapeutic potential for stimming.
The rat models in the study were treated with Korean Red Ginseng (either 100 mg per kg per day or 200 mg per kg per day, for a total of three weeks). To test the effects of the supplement on stimming behavior, the researchers used a slightly-modified version of the Marble Burying Test, which measures stereotypic and repetitive behaviors. In the rats that received the low dose and the high dose of Korean Red Ginseng, the researchers observed statistically significant positive outcomes. Although the study did not reveal the mechanism of action through which the ginseng mediated this behavior, previous studies have highlighted the potential of Korean Red Ginseng in supporting the body’s natural inflammatory response.* Inflammation is associated with symptoms of autism, suggesting a possible connection.
In a 2017 study, scientists at Jilin University in China utilized a similar valproic acid-exposed rat model to explore the benefits of vitamin D for stimming. They treated rats with 80,000 IU per kg per day and observed significant improvements on repetitive behavior tests. They also measured the levels of vitamin D in the rats’ blood and reported a negative linear relationship between repetitive behavior scores and vitamin D levels. This close correlation strongly suggests the stereotypic behavioral changes in the rat models were linked to the vitamin D supplementation. Although the study does not provide a biochemical mechanism to explain the relationship, the known properties of vitamin D in supporting the body’s natural inflammatory response could be playing a role.
Although clinical studies on the effects of nutritional supplements on stimming are limited, there are several that highlight some of the most promising options. For instance, a 2017 meta-analysis that combined data from six randomized clinical trials identified omega-3 fatty acid supplementation as a potentially viable therapy for stimming, possibly due to the properties of these compounds to support the body’s natural inflammatory response. The pooled data included a total of 109 patients and revealed statistically significant improvements in stereotypic behaviors. Although the six studies were small, the combined results suggest that large-scale, randomized clinical trials on omega-3 fatty acids supplements for providing nutritional support for stimming are warranted in the future.
Another intriguing study by researchers at Massachusetts General Hospital and Harvard Medical School highlights the potential of using sulforaphane supplementation for stimming. Sulforaphane is a phytochemical extract derived from fresh broccoli sprouts and is known to upregulate genes that resist oxidative stress, inflammation, and DNA damage, all of which are believed to be involved in stimming in autistic children. Supplementing with sulforaphane has no known side effects.
In this randomized, double-blind, placebo-controlled study, the authors treated 29 young men (ages 13 to 27) with moderate to severe ASD with 50-150 uL of oral sulforaphane every day for 18 weeks. They then used three behavioral measurement tests to determine the effects. Ultimately, sulforaphane supplementation was associated with improved scores on both the Aberrant Behavior Checklist (34 percent) and the Social Responsiveness Scale (17 percent). On the Clinical Global Impression Improvement Scale, statistically significant improvements were observed for abnormal behaviors (including stimming), as well as social interaction and verbal communication.
Because the evidence is preliminary, it is important to remember that these four supplement options—Korean Red Ginseng, vitamin D, omega-3 fatty acids, and sulforaphane—are not the only possible supplements for managing stimming. Therefore, it is helpful to identify the mechanistic similarities between them when considering future research directions. Most notably, all of them enhance the body’s natural inflammatory response. This suggests that other nutritional supplements with such properties, such as curcumin, could provide similar benefits.* Like Korean Red Ginseng, curcumin has been used in traditional medicine for thousands of years, and scientists are investigating how curcumin’s properties might benefit patients with complex conditions like autism. The promising findings on the benefits of sulforaphane also suggest that other phytochemical supplements, like quercetin, are worthy of further exploration. Quercetin shares structural and functional properties with sulforaphane, and it has known bioactivity in the central nervous system, so it presents another possible therapeutic option for autistic patients.
For the research community, the next steps are clear: build on the existing evidence by conducting well-designed, large-scale clinical trials of the nutritional supplements with the most promise for addressing stimming behavior in autistic patients. For practitioners, it makes sense to consider these supplements today as options for patients who are non-responsive to the current behavioral and pharmacological therapies for stimming. Given the low toxicity of these supplements and the base-level evidence supporting their efficacy, they could prove beneficial for certain patients.
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