Leaded gas created a mental health crisis for this generation
Researchers have long warned about the harmful effects of lead in paint, pipes and other products. But another once-widespread source − leaded gasoline − might have harmed the mental health of a generation.
Gen X bears an extra burden of conditions such as depression, anxiety, ADHD and neurotic behavior because of the leaded gasoline they were exposed to as children, according to a study published Wednesday in the peer-reviewed Journal of Child Psychology and Psychiatry.
Leaded gas was banned in the United States in 1996, but the study said years of exposure during development made them particularly vulnerable. Lead gas peaked from the mid-1960s through the mid-1970s, and children born during that era would later develop some of the highest rates of mental health symptoms, the study said.
The study also linked leaded gas to "disadvantageous" traits, such as struggling to concentrate, stay on task or organizing thoughts.
"I tend to think of Generation X as 'generation lead,'" said Aaron Reuben, a study co-author and assistant professor of clinical neuropsychology at the University of Virginia. "We know they were exposed to it more and we're estimating they have gone on to have higher rates of internalizing conditions like anxiety, depression and symptoms of attention deficit hyperactivity disorder."
What did the study measure?
Reuben and researchers from Florida State University examined health survey and national gas use data to estimate the amount of lead in people from 1940 through 2015. They used that data to estimate the mental health effects of such exposures.
Researchers linked the lead exposure to an estimated 151 million "excess mental disorders" in the United States over the 75-year period. The estimates should be "considered a floor" because it relies mainly on gas and not exposure from lead in paint and pipes, Reuben said.
Although lead paint was banned in 1978, it still can be found in older homes and present hazards to children who ingest paint chips, for example. The Environmental Protection Agency warns parents of children living in older homes to be aware of high-use areas such as window sills, doors, door frames, stairs, railings, banisters and porches.
Lead can disrupt children's brain development, fine motor skills and emotions. Low levels can cause behavioral problems, loss of IQ and attention deficit disorders.
Which age groups are at most risk?
Mental illness symptoms attributed to lead exposure varied significantly by age groups. Those born in 1940 and 2015 had among the lowest levels.
Those born between 1966 and 1986 generally had higher mental illness levels linked to lead exposure with the rates peaking for those born between 1966 and 1970, the study said. Those rates coincided with the peak use of lead in gas from the mid-1960s through the mid-1970s.
Why was lead added to gas?
Lead was added to gas to improve engine performance and eliminate engine knocking. As cars burned the fuel, emissions spread into the atmosphere and accumulated in dust, soil and the lungs of millions of people.
Use of leaded gas tapered in the mid-1970s because the fuel damaged catalytic converters that became more common to meet stricter emission standards required by the 1970 Clean Air Act.
What effect did leaded gas have on people?
The study said the peak lead use coincided with increased demand for psychiatric care and higher rates of juvenile delinquency. The study cited earlier research detailing the "lead-crime hypothesis" that suggested lead abatement might have contributed to lower murder rates from the 1990s through the 2010s.
Now, children are routinely screened for high lead levels in their blood and treated if their levels are concerning.
"In the 60s, 70s and 80s, folks were walking around with an average blood lead value that today would trigger clinical follow-up," Reuben said.