Research Shows Autism Risk Raised When Drinking Water Contains Lithium

While scientists know that autism spectrum disorder is caused by changes in the brain, there's still a lot we don't know about the condition, according to the Centers for Disease Control and Prevention (CDC). There are multiple genetic, biological, and environmental risk factors that can make someone more likely to develop autism, such as experiencing complications when you're born or having a sibling with the same disorder. But a new study published in JAMA Pediatrics found that lithium in drinking water could also be an environmental risk factor for the disorder.

Autism spectrum disorder (ASD) is a developmental condition that's often apparent by the time a child is one year old, according to the American Psychiatric Association (APA). While the amount it can impact an individual's functioning varies from person to person, ASD typically causes challenges with restricted interests, social communication, and repetitive behavior. Early signs can include having trouble coping with changes to routine, stilted speech, difficulty making friends, sensory hypersensitivity, and arranging toys in a particular way. ASD is diagnosed through an extensive evaluation through your pediatrician or local school. While ASD is a lifelong condition, those with autism and their families can learn adaptive skills through occupational therapy, parent management training, and speech therapy.

There are many different risk factors that can contribute to a child developing ASD, including complex genetic factors and having older parents (via APA). There can also be environmental factors, which scientists are still studying. A 2023 study published in JAMA Pediatrics explored the link between pregnant women who drank tap water containing lithium and the likelihood of their children being diagnosed with ASD (via UCLA Health). Researchers studied a Danish database that included 12,799 children diagnosed with ASD and 63,681 children without an ASD diagnosis born between 1997 and 2013. They identified which public waterworks supplied pregnant mothers' homes and determined that when lithium levels increased, the risk of an ASD diagnosis in children did as well. In areas with the top 25% of recorded lithium levels, the risk of ASD was 46% higher than areas in the bottom 25%.

Dr. Beate Ritz, lead study author and professor at the David Geffen School of Medicine at UCLA and the UCLA Fielding School of Public Health, told UCLA Health that this study was important since lithium batteries are being used more often and thrown away in landfills, which could contaminate groundwater. However, more studies are needed on how lithium can impact brain growth and development.