Lead poisoning and criminal activity

Imagine that a neurotoxin had been introduced into the brain of a significant portion of the population that resulted in a lower IQ, impulsive behavior and aggression. Does that sound like a recipe for crime? Well there is some very Strong data that suggest this is precisely what has resulted from lead poisoning.

Deborah Denno, a professor at Fordham University School of Law, conducted an extremely detailed study in which she followed 1000 children from birth to age 22 and looked at 3000 different factors in an attempt to find what the best predictor in children is for aggressive behavior in school, juvenile delinquency and eventual criminal activity. Denno's research found that the best predictor (when children are 7 years old) for theses activities is the degree of lead poisoning.

Dr. Herbert L. Needleman, M.D., Professor of Psychiatry and Pediatrics at the University of Pittsburgh School of Medicine, was the first to discover the cognitive effects in children who had been exposed to lead poisoning. His findings started the national efforts to remove lead from paint, gasoline and water pipes throughout the U.S. in the 1970s. Dr. Needleman has continued to study the effects of lead poisoning and has said, "
"When environmental lead finds its way into the developing brain, it disturbs neural mechanisms responsible for regulation of impulse. That can lead to antisocial and criminal behavior"

Perhaps the most thorough studies on lead poisoning have come from Rick Nevin. Nevin was hired by the Department of Housing and Urban Development to do a cost benefit analysis of removing lead paint from public housing. Nevin did not set out with any link to crime in mind, but later stated that he was stunned to discover a strong relationship between the use of leaded gasoline and violent crime. He conducted a ten year study on the effects of lead poisoning. Nevin concluded that much of the crime trends in the U.S. over the last 100+ years can be explained by lead poisoning.

He suggested that a spike in lead poisoning would lead to a spike in criminal activity approximately 20 years later while a decline in lead poisoning would lead to a decline in criminal activity approximately 20 years later. For instance, there was a spike in lead in NY city after WWII that lasted through the early '70s. Then, in the early '70s NYC took an unusually aggressive approach to ridding their city of lead. The city had managed to drastically decrease the amount of lead in paint, gasoline and water pipes by around 1973-1974. If Levin's theory is true then violent crime in NYC would increase during the late '60s, 70s, '80s and early '90s, peaking around 93 or 94, and then began to decrease. In 1990, 31 out of 100,000 New Yorkers were murdered. In 2004 that rate had declined to 7 per 1000. From 1994 to 2001 homicides fell by 67% and overall crime decreased by 57%.

Nevin pointed out that the U.S. has had two spikes of lead poisoning. The first around the turn of the 20th century, linked to household paint, and the second after WWII, linked to gasoline. Both times the national violent crime rates increased, peaked at around 20 years, and then decreased.
Just a coincidence? Perhaps. But this is only the tip of the iceberg, Nevin's predictions seem to hold true in other countries as well as in more local communities.

A few examples;
Chicago's Robert Taylor Homes were built over the Dan Ryan Expressway in 1962. Approximately 150,000 cars drove by these homes each day, cars pumping out lead filled exhaust. A study of children who grew up in these homes during the 60's and 70's found that they were 22 times more likely to be murderers than people living elsewhere in Chicago.
In 2001 Sociologist Paul B. Stretesky and Ciminologist Michael Lynch published a study in which they had looked at different U.S. counties with high and low lead levels. They found that the counties with high lead levels had four times the murder rate of counties with low lead levels.
In 2006, Dr. Needleman compared the lead levels of 194 adolescents who had been arrested in Pittsburgh with lead levels of 146 high school adolescents who had not been in trouble. The arrested youth had lead levels that were four times higher.

After examining some of these studies as well as others, the Arizona School Boards Association published an article in 2002 in which they said, “These studies show that lead poisoning may ultimately be behind much of the plague of drug abuse and alcoholism in public schools that parent and non-parents specifically identified in polls as one of the biggest problems facing public schools.”


One thing that is important to note in this discussion is that the general public has a misconception regarding the increase of crime. People see stories of crime on their local news and have no doubt that there is more crime committed today than ever before. This is simply not true, in actuality there has been a a sharp decline in criminal activity. According to the D.O.J. Bureau of Justice Statistic's 2003 criminal victimization report, violent crimes decreased by 55% between 1993 and 2003 and property crimes declined 49% during that time. Despite what your parents may tell you, things are not much worse now than they use to be "back in the good ole days."