Adults who were exposed to lead during their childhood are more likely to experience mental health problems and develop unhealthy personality traits, according to a new study published in JAMA Psychiatry, reports Medical News Today.

Researchers from Duke University in Durham, North Carolina, reviewed the data of more than 1,000 participants born in 1972 and 1973 in Dunedin, New Zealand, which at the time was one of several countries that added high levels of lead to gasoline.

Of those involved in the study, 579 youngsters received blood tests when they were 11 years old to measure their lead exposure levels. Scientists found that 94 percent of these kids had accumulations of lead levels higher than 5 micrograms per deciliter of blood (ug/dL). (Today, blood lead levels of 5 ug/dL would result in an immediate medical referral.)

Researchers regularly administered mental health assessments to participants up until age 38 and measured their psychopathology factor (p-factor)—a mental health score—by looking at 11 disorders, including drug dependence, major depression, phobias and schizophrenia.

Findings showed that individual’s exposed to lead in childhood developed more neurotic tendencies and were less agreeable and conscientious.

“When we see changes that may be the result of lead exposures in New Zealand, it’s very likely that you would have seen those same impacts in America, in Europe, and other countries that were using leaded gasoline at the same time,” said Aaron Reuben, MEM, a study coauthor.

According to Jonathan Schaefer, MA, another coauthor, those who plan to create interventions to help those exposed to lead as kids should consider their long-term care needs.

In the future, researchers would like to examine whether childhood lead exposure could also influence the development of neurodegenerative diseases, such as dementia.

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