Smoking When Pregnant Tied to Risk That Offspring Will Be Criminals

Can young men and woman who commit murder, robbery, rape, assault, theft, fraud, forgery, blackmail, embezzlement, vandalism, prostitution, narcotics offenses, or other crimes blame it on how many cigarettes their mothers smoked during pregnancy?

Maybe.

A dose-response relationship has been found between the arrests of young men and women for such crimes and how many cigarettes their mothers smoked during the last trimester of pregnancy.

The finding comes from a study conducted by Patricia Brennan, Ph.D., an assistant professor of psychology at Emory University in Atlanta, and reported in the January American Journal of Psychiatry.

The persons Brennan and her colleagues decided to use as subjects for their study were some 8,000 individuals who had been born in Copenhagen, Denmark, between 1959 and 1961. Extensive demographic and medical information was gathered for each of these individuals before, during, and after their births. And it was this extensive data bank that Brennan and her coworkers wanted to tap for their study.

For instance, whether the fathers of the individuals had a criminal history had been determined from the Danish criminal register. Whether the fathers or mothers of the individuals had ever been hospitalized for psychiatric or substance-abuse problems was ascertained from the Danish psychiatric register. Whether any of the individuals had experienced pregnancy or delivery complications was discovered in national obstetric records. And whether the mothers of any of the individuals had smoked during the last three months of pregnancy—and if so, how much—was determined via interviews with the mothers during pregnancy or shortly after delivery.

Then, in 1994, Brennan and her colleagues determined which of the 8,000 individuals who were included in their study had gone on, as adults, to engage in criminal acts. The researchers used as their source the Danish criminal register. The crimes included murder, robbery, rape, assault, illegal possession of a weapon, theft, breaking and entering, fraud, forgery, blackmail, and embezzlement, among others.

Brennan and her team then used the data that had been collected about the 8,000 subjects back in 1959-61 and the data they collected in 1994 to answer this question: Was there a link between maternal smoking during the last three months of pregnancy and offspring committing crimes?

They analyzed their data for male and female offspring separately. They also considered socioeconomic status, pregnancy complications, parents’ psychiatric or substance-abuse problems, or other factors that might have distorted their findings.

They discovered that there was indeed a link between maternal smoking during the last three months of pregnancy and criminal behavior in both male and female offspring. Even more intriguing, there was a dose-response relationship between maternal smoking during the last three months of pregnancy and criminal behavior in both male and female offspring (see chart).

The dose-response relationship was especially evident in the male offspring. Some 25 percent of male subjects whose mothers had smoked no cigarettes at all during the last trimester of pregnancy were arrested for crimes; about 32 percent of male subjects whose mothers had smoked one to two cigarettes during the last trimester had been arrested; about 34 percent whose mothers had smoked three to 10 cigarettes a day during the last trimester had been arrested; and some 38 percent whose mothers had smoked more than 10 cigarettes daily during the last trimester had been arrested.

And in yet another arm of their study, Brennan and her coworkers wanted to find out whether there was a link between maternal smoking during the last three months of pregnancy and offsprings’ substance abuse. Once again, they used data that had been collected about the 8,000 subjects back in 1959-61, but also data that they had collected about the subjects in 1999. And these data, which they culled from the Danish psychiatric register, revealed which of the subjects had been hospitalized for abusing substances. And once again, they took into consideration factors that might have confounded their results.

The researchers found a significant relationship between maternal smoking during the last trimester of pregnancy and offspring abusing substances. As with the link between maternal smoking and criminal behavior, the association with substance abuse included female as well as male offspring. And once again the association was a dose-response one.

Then Brennan and her coworkers combined the two arms of their study to see whether the relationships between maternal smoking and criminality and substance abuse among offspring might be intertwined.

First they attempted to find out whether the connection between maternal prenatal smoking and substance abuse in offspring might be due to the offsprings’ committing crimes, and that criminal activity in turn then lured them into substance abuse. However, they found the link to be independent of any criminal behavior.

They then tried to determine whether the tie between maternal prenatal smoking and criminal activity in offspring might actually be due to offspring abusing substances, and that abuse in turn pointing them toward criminal activity. They found that this was not the case for the male offspring, but that it was so for the female ones.

The researchers thus concluded that “maternal prenatal smoking is related to criminal and substance-abuse outcomes in male and female offspring.” But the smoking–criminal behavior link in female offspring appears to be explained by an increased risk for substance abuse that then leads to an increased risk for arrest, they add.

Psychiatric News asked Brennan whether she and her colleagues plan more studies along this line. “We are going to do a study on self-reports of crime and how they are related to maternal smoking during pregnancy,” she replied. “This study will also be based in Denmark.”

The study report, “Relationship of Maternal Smoking During Pregnancy With Criminal Arrest and Hospitalization for Substance Abuse in Male and Female Adult Offspring,” can be found on the Web at http:ajp.psychiatryonline.org by searching under the January issue. ▪

AM J PSYCHIATRY 2002 159 48