For parents of children with autism spectrum disorder (ASD), 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 a child with autism 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 patient, there is increasing interest within the research and clinical communities in nutritional supplements for 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 antioxidant and/or anti-inflammatory properties, including curcumin and quercetin, present the best prospects for future laboratory and clinical research.
Promising Evidence in Animal Models of Stimmingseveral 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 may have therapeutic potential for reducing symptoms of autism, including 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 about three weeks). To test the effects of the supplement on stimming behavior, the researchers used a slightly-modified version of the well-established Marble Burying Test, which measures stereotypic and repetitive behaviors. In both the rats that received the low dose and the high dose of Korean Red Ginseng, the researchers observed statistically significant improvements in the outcomes on this test. Although the study did not reveal the mechanism of action through which the ginseng may have mediated this behavioral effect, previous studies have highlighted the anti-inflammatory activities of Korean Red Ginseng. Inflammation is has been associated with symptoms of autism, suggesting a possible connection.
In a 2017 study from the journal Psychiatry Research, a group of scientists at Jilin University in China utilized a similar valproic acid-exposed rat model to highlight the possible benefits of vitamin D as a supplement for stimming and other behavioral symptoms of autism. They treated rats with 80,000 IU per kg per day and observed significant improvements on repetitive behavior tests. Moreover, the scientists 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 that the stereotypic behavioral changes in the rat models were directly linked to the vitamin D supplementation. Again, the study does not provide a biochemical mechanism to explain the relationship, but the known anti-inflammatory activities of vitamin D could be playing a role.
Tentative Evidence from Clinical Studies on Supplements for Stimming
So far, clinical studies on autism supplements for stimming are limited, but there are a few that highlight some of the most promising options. For instance, a 2017 meta-analysis published in Neuropsychiatric Disease Treatment combines data from six randomized clinical trials to implicate omega-3 fatty acid supplementation as a potentially viable therapy for stimming, possibly due to the antioxidant and anti-inflammatory properties of these compounds. The pooled data from the four studies in the meta-analysis included a total of 109 patients, and the subsequent evaluation of the combined data revealed that there were statistical improvements in stereotypic behaviors among these patients. It is important to note that these were all small studies, but the significance of the combined results suggests that large-scale, randomized clinical trials on omega-3 fatty acids as supplements for stimming are warranted in the future.
Another intriguing study, which was published in 2014 by a group of researchers associated with Massachusetts General Hospital and Harvard Medical School, highlights the possibility of using sulforaphane as a supplement for stimming. Sulforaphane is a phytochemical extract derived from fresh broccoli sprouts and is known to upregulate genes that fight oxidative stress, inflammation, and DNA damage, all of which are believed to be involved in ASD symptoms that lead to stimming. Even better, the supplement 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 a total of 18 weeks. They then used three previously-established behavioral measurement tests to determine the effects. Ultimately, the sulforaphane supplement improved scores on the Aberrant Behavior Checklist by 34 percent and the Social Responsiveness Scale by 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.
Supplement Candidate Similarities and Future Research Directionssuch as curcumin, could also provide similar benefits. Like Korean Red Ginseng, curcumin is a compound that has been used in traditional medicine for thousands of years, and scientists today are increasingly interested in exploring how its antioxidant and anti-inflammatory activities could benefit patients with complex conditions like autism. In addition, the promising findings on the benefits of sulforaphane suggest that other phytochemical supplements, like quercetin, may be 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 option for patients with autism.
For the research community, the next steps are clear: build on the existing evidence by conducting well-designed, large-scale clinical trials of the antioxidant and anti-inflammatory supplements with the most promise for reducing stimming behavior in autism patients. For practitioners, it may make sense to start considering these supplements today as therapeutic options for patients who are non-responsive to the current behavioral and pharmacological treatments for stimming. Given the low toxicity of these supplements and the base-level evidence supporting their efficacy, the could prove beneficial for certain patients.
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