A new study published in the Journal of Child Psychology and Psychiatry looked at the contribution of childhood lead exposure to psychopathology in the US population over the past 75 years.
“We set out to determine the toll that leaded gasoline took on the US population’s mental health over the past century,” Dr. Aaron Reuben told us. “We knew it would be higher than anyone previously understood.”
The research team knew lead harms mental health. What was unknown was how large a role lead may have played in the country’s mental health and personality. They expected to demonstrate harm, but were unprepared for the magnitude the impact.
“We are gradually trying to better understand the role that lead has played in the health and welfare of our country over the past century,” Dr. Reuben told us. “There is much work left to do.”
The research team combined serial, cross-sectional blood–lead level (BLL) data from National Health and Nutrition Examination Surveys (NHANES) with historic leaded-gasoline data to estimate US childhood BLLs from 1940 to 2015 and calculate population mental-health symptom elevations from known lead-psychopathology associations.
The researchers estimate that by 2015, the US population had gained 602-million General Psychopathology factor points because of exposure arising from leaded gasoline, reflecting a 0.13-standard-deviation increase in overall liability to mental illness in the population and an estimated 151 million excess mental disorders attributable to lead exposure.
“We were surprised by the magnitude,” Dr. Reuben told us. “My goodness. So many people were exposed to lead, and it irretrievably shifted the population’s mental health towards more illness and distress. We need to re-evaluate global trends in mental health, both in America and worldwide, and understand that lead exposure undoubtably played a role in generational trends.”
Dr. Reuben also believes we need to understand that the benefit of removing lead hazards always outweighs the cost and everything should be done possible to limit new exposures.