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Autism rates have been increasing at a disturbing clip and scientists still don’t have a firm understanding of the causes or contributing factors that lead to the development of the condition. Data suggests toxicological exposures, impaired detoxification and changes in the gastrointestinal microbiome all likely play a role (Alabdali 2014, Volk 2022, Vuong 2017).

Lithium Exposure During Pregnancy

Lithium is an element commonly encountered in low levels throughout the environment. One of the most common sources of exposure to lithium is from drinking water. While studies have clearly associated lithium drinking water levels with reduced suicide risk and suggested a connection with reduced incidence of dementia, potential effects during pregnancy are not as well explored. A recent study out of Denmark examined the incidence of autism and exposure to groundwater lithium levels and found a potential correlation (Liew 2023).

Due to Denmark’s comprehensive national health-care system, data on autism rates were readily available. Cases were then mapped to residential addresses which were compared with earlier data on lithium groundwater levels. The researchers found a small, but significant, increased risk of autism correlated with lithium. In the highest exposure group, the incidence of autism appeared to increase by 46%. With a countrywide estimated autism rate of 1 in 145 children, higher exposure to lithium in drinking water would increase that risk to 1 in 100 according to the study.

The findings are interesting, but far from conclusive. Research from Argentina in the Andes mountains, where lithium levels in the local water are much higher than in Denmark, did find an association with groundwater lithium levels and low birth weight. Unfortunately, neurodevelopmental outcomes, including autism, were not tracked (Harari 2015).

While I am not a research scientist or a statistician, a number of criticisms of the study have been recently reported:

  • Research on mothers taking lithium medication during pregnancy have not found a link to autism even though lithium intake would be up to 10,000 times higher than levels consumed from tap water (Poels 2018). However, studies on autism from exposure to lithium medication during pregnancy are small and more data are needed to fully rule out a connection.
  • Lithium in tap water is not the only source of lithium in the diet. Approximately one-third of lithium exposure comes from food which could have impacted the results.
  • There were no measurements taken in the study that confirmed a mother’s actual exposure to lithium. If individuals used a water filter or purchased bottled water, these factors were not taken into account.
  • Past research on the correlation of local groundwater lithium levels to exposure, measured by serum or urinary levels of the mineral, have found fairly poor correlations between the two (Bellinger 2023). In other words, local levels of lithium aren’t well correlated with intake, exposing a potentially serious flaw in the study’s design.
  • The study relies on cases of children with autism being diagnosed, which is affected by the proximity and availability of effective medical services. While the authors attempted to adjust for these factors, nuances may have been missed. Groundwater lithium levels are highest in the dense population centers of Denmark where getting a proper diagnosis would be easier than the countryside. This may have artificially inflated data on autism rates in the cities where lithium levels are higher.
  • Lithium levels in groundwater are stable over time. Lithium from tap water could not account for the sharp increases in cases of autism seen over the past few decades. Something other than lithium is likely driving the rapid increases in autism rates throughout the world.
  • The study only looked at the data from one small, wealthy country. This may not be representative of other populations or locations.

Autism is a complex condition, most likely due to a multitude of factors involving genetic and environmental stressors that have been steadily increasing its incidence over time. Microdoses of lithium from tap water cannot account for these changes. We may want it to be simple, but unfortunately, it never will be.

Many of us functional and integrative health-care providers have seen dramatic improvements in autism cases by treating infections, nutritional deficiencies and toxic metals. These are often core driving factors of the condition that should not be overlooked.

When to Use Lithium as a Treatment

Overall, even with the criticisms outlined above, the study still raises potential concerns over lithium intake and neurological development. It is a reminder of why I recommend avoiding lithium supplementation in women during pregnancy. Based on our current knowledge set, we still don’t fully understand the risks of lithium during fetal development and should proceed with caution until more data are available.

With all that being said, it is also worth remembering the benefits with lithium, both as a low-dose supplement and for the treatment of bipolar disorder. In my own clinical experience with thousands of patients, lithium has been an invaluable tool for helping to manage irritability, anger, addiction, dementia and suicide. Regardless of the eventual findings on lithium exposure during pregnancy, beneficial outcomes are well established when lithium is used appropriately.

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Alabdali A, Al-Ayadhi L, El-Ansary A. A key role for an impaired detoxification mechanism in the etiology and severity of autism spectrum disorders. Behav Brain Funct. 2014;10:14. Published 2014 Apr 28. doi:10.1186/1744-9081-10-14

Volk HE, Ames JL, Chen A, et al. Considering Toxic Chemicals in the Etiology of Autism. Pediatrics. 2022;149(1):e2021053012. doi:10.1542/peds.2021-053012

Vuong HE, Hsiao EY. Emerging Roles for the Gut Microbiome in Autism Spectrum Disorder. Biol Psychiatry. 2017;81(5):411-423. doi:10.1016/j.biopsych.2016.08.024

Liew Z, Meng Q, Yan Q, et al. Association Between Estimated Geocoded Residential Maternal Exposure to Lithium in Drinking Water and Risk for Autism Spectrum Disorder in Offspring in Denmark [published online ahead of print, 2023 Apr 3]. JAMA Pediatr. 2023;e230346. doi:10.1001/jamapediatrics.2023.0346

Harari F, Langeén M, Casimiro E, et al. Environmental exposure to lithium during pregnancy and fetal size: a longitudinal study in the Argentinean Andes. Environ Int. 2015;77:48-54. doi:10.1016/j.envint.2015.01.011

Bellinger DC. Lithium in Drinking Water-A Novel Environmental Risk Factor for Autism Spectrum Disorder? [published online ahead of print, 2023 Apr 3]. JAMA Pediatr. 2023;10.1001/jamapediatrics.2023.0330. doi:10.1001/jamapediatrics.2023.0330

Poels EMP, Bijma HH, Galbally M, Bergink V. Lithium during pregnancy and after delivery: a review. Int J Bipolar Disord. 2018;6(1):26. Published 2018 Dec 2. doi:10.1186/s40345-018-0135-7