Childhood lead exposure may have contributed to an estimated 151 million excess mental health disorders by 2015.

McFarland MJ, Reuben A, Hauer M. Contribution of childhood lead exposure to psychopathology in the US population over the past 75 years. Journal of Child Psychology and Psychiatry. 2024.

A new study looked at the impact of historic leaded gasoline on childhood blood lead levels (BLL) and mental health outcomes over the last 75 years.

“A significant burden of mental illness symptomatology and disadvantageous personality differences can be attributed to US children's exposure to lead over the past 75 years,” the researchers wrote. “Lead's potential contribution to psychiatry, medicine, and children's health may be larger than previously assumed.”

The study focused on children born between 1940 and 2015. Within that range, the researchers found that lead-associated mental health and personality differences were most pronounced for people born between 1966 and 1986: Generation X.

Lead exposure and health risks

The study looked at childhood lead exposure from leaded gasoline, which was phased out of automobiles in the United States in the 1990s—a change that was cited as a public health success.

Angrand RC, Collins G, Landrigan PJ, et al. Relation of blood lead levels and lead in gasoline: an updated systematic review. Environmental Health. 2022;21(1).

However, gasoline is not the only product through which people have been or may be exposed to lead. Lead paint, which was banned in 1978 but may still linger in some older buildings, has also been a contributor to lead exposure risks. Lead can also be found in some water systems, soil, and imported toys.

Chuck E. Lead in gasoline tied to over 150 million excess cases of mental health disorders, study suggests. NBC News. December 4, 2024.

Researchers say that more studies may be needed to fully understand the contribution of lead exposure to mental health in the US.