Summary: A new study estimates that childhood lead exposure, peaking between 1960 and 1990 due to leaded gasoline, caused 151 million excess cases of mental illness by 2015. Researchers linked historic lead exposure data to mental health symptoms, finding that personality changes and mental health disorders were most pronounced among Generation X.
This underscores the lasting impact of environmental toxins on public health, with leaded gasoline serving as a cautionary tale for prioritizing profit over safety. The findings highlight the need to address environmental risks proactively to prevent long-term societal harm.
Key Facts:
- Childhood lead exposure contributed to 151 million excess mental health disorders.
- Generation X experienced the most pronounced mental health impacts.
- The study stresses the importance of proactive regulation of environmental toxins.
Source: Wiley
New research published in the Journal of Child Psychology and Psychiatry indicates that childhood lead exposure, which peaked from 1960 through 1990 in most industrialized countries due to the use of lead in gasoline, has negatively impacted mental health and likely caused many cases of mental illness and altered personality.
For the study, investigators combined blood–lead level data from National Health and Nutrition Examination Surveys with historic leaded gasoline data. (Leaded gas was phased out in United States by 1996.) They estimated US childhood blood–lead levels from 1940 to 2015 and assessed mental-health symptoms that have been linked to lead exposure.
Assuming that published associations of lead with illnesses are causal and not purely correlational, the team estimated that by 2015, there were 151 million excess mental disorders attributable to lead exposure. Lead-associated mental health and personality differences were most pronounced for people born from 1966 through 1986 (Generation X).
“Society frequently operates under the presumption that environmental exposures are safe until proven otherwise. Leaded gasoline wasn’t needed as an anti-knock agent—there were alternatives available. It was profitable. An abundance of incontrovertible evidence occurring across decades was required to ban it,” said corresponding author Michael McFarland, PhD, of Florida State University.
“By documenting the widespread consequences of exposure, this study underscores the folly of such thinking and highlights the long-lasting health consequences of exposure to the population.”
About this mental health and environmental neuroscience research news
Author: Sara Henning-Stout
Source: Wiley
Contact: Sara Henning-Stout – Wiley
Image: The image is credited to Neuroscience News
Original Research: Closed access.
“Contribution of Childhood Lead Exposure to Psychopathology in the US Population over the Past 75 Years” by Michael McFarland et al. Journal of Child Psychology and Psychiatry
Abstract
Contribution of Childhood Lead Exposure to Psychopathology in the US Population over the Past 75 Years
Background
More than half of the current US population was exposed to adverse lead levels in childhood as a result of lead’s past use in gasoline. The total contribution of childhood lead exposures to US-population mental health and personality has yet to be evaluated.
Methods
We 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.
We utilized five outcomes: (1) General Psychopathology “points”, reflecting an individual’s liability to overall mental disorder, scaled to match IQ scores (M = 100, SD = 15); (2) Symptoms of Internalizing disorders (anxiety and depression) and Attention-deficit/Hyperactivity Disorder (AD/HD), both z-scored (M = 0, SD = 1); and (3) Differences in the personality traits of Neuroticism and Conscientiousness (M = 0, SD = 1).
Results
Assuming that published lead-psychopathology associations are causal and not purely correlational: We 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.
Investigation of specific disorder-domain symptoms identified a 0.64-standard-deviation increase in population-level Internalizing symptoms and a 0.42-standard-deviation increase in AD/HD symptoms.
Population-level Neuroticism increased by 0.14 standard deviations and Conscientiousness decreased by 0.20 standard deviations. Lead-associated mental health and personality differences were most pronounced for cohorts born from 1966 through 1986 (Generation X).
Conclusions
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. Lead’s potential contribution to psychiatry, medicine, and children’s health may be larger than previously assumed.
