Is leaded gasoline the main cause of increasing mental illnesses?

New research shows that lead is a hidden poison. Researchers have investigated the damaging effects of leaded gasoline on the mental health of millions of Americans. Lead, in various forms, has been used in many everyday products for thousands of years. The Romans even added it to wine as a sweetener. However, its most widespread use was to add it to gasoline.

According to a new study published in the Journal of Child Psychiatry, this use is associated with an increase in mental health disorders.

Americans, especially those born between 1966 and 1986 (primarily Generation X), likely developed 151 million additional mental health disorders that would not have occurred due to the use of leaded gasoline. The study found an increase in anxiety and depression, attention deficit hyperactivity disorder (ADHD), and neuroticism, as well as a decrease in conscientiousness. Although the toxicity of lead to humans has been known for almost as long as its use, we are still fully discovering the effects and levels of exposure.

Concerns about the safety of leaded gasoline were raised soon after one of the engineers who made the discovery, as well as several workers manufacturing the additive, fell ill and some died of mysterious illnesses. However, the US Surgeon General dismissed these concerns, citing a lack of evidence of effects at low levels of exposure associated with driving.

The debate over the effects of lead exposure at the time was dominated by industry-sponsored studies, as described in a 2009 book titled The Lead Wars: The Politics of Science and the Fate of America‘s Children. At the same time, lead paint was also marketed as the best color for its washability and brightness.

In the 1970s, the invention of a catalytic converter that did not work with leaded gasoline and a growing body of evidence about the negative consequences of lead exposure for human health initiated the phase-out of leaded gasoline. (Also in 1978, regulations were enacted in the United States to ban lead paint for residential purposes). Even though its use had already declined, Britain banned leaded gasoline in 1999, and Algeria was the latest country to officially ban it in 2021.

The gradual reduction of lead in the environment has provided a useful environment for researchers to expand our understanding of the wide-ranging consequences of lead exposure among children and adults. For example, a study in Sweden compared children born in areas near highways, which were more exposed to lead emissions from cars, with those born further away.

By studying how the differences between the two groups changed over time as leaded gasoline was phased out, they found that lead exposure reduces educational outcomes, increases the risk of criminal activity, and can reduce lifetime earnings. These effects on crime, educational achievement, and participation in “risky behaviors” have also been observed in the United States.

Lead mimics calcium in the body and disrupts most systems that require calcium to function. This substance is associated with reduced cognitive function as well as kidney and cardiovascular diseases, high blood pressure and even fertility problems. For example, taking advantage of the fact that leaded gasoline was still allowed at NASCAR races, a study from the United States found that cardiovascular disease mortality rates in older adults living near NASCAR tracks dropped just as the races began. It is in progress, it is higher.

The first estimate of the effects on American society

A new study in the Journal of Child Psychology and Psychiatry builds on known links of lead exposure to mental health from two studies in Chicago and New Zealand. Given the relationship between lead exposure and these outcomes, measured childhood lead exposure and lead emissions in each year, the researchers calculated the fraction of changes in mental health among Americans born in different years that could attributed to lead.

This approach is not perfect, as other things were also changing over time. However, this study provides the first estimate of the effects of leaded gasoline on American society. Since lead was not only used in gasoline, its harmful legacy is probably even greater. And other uses of lead are increasing. For example, it is used in batteries that power electric vehicles.

Such a study was not possible in the UK, as no nationally representative data on lead exposure have been collected. However, lead particles from leaded petrol are still found on the streets of London. So it is likely that lead has caused, and perhaps continues to cause, considerable physical and mental impairment in Britain. To see other news, visit Tekna medical news page.