Cocaine Exposure During Pregnancy Leads To Impulsivity In Male, Not Female, Monkeys

In a recent study done at Wake Forest University School of Medicine adult male monkeys exposed to cocaine while in the womb have poor impulse control and may be more vulnerable to drug abuse than female monkeys.
For the study, researchers compared adult monkeys, both male and female, prenatally exposed to cocaine more than 15 years ago, to monkeys who were raised under similar conditions, but not exposed to cocaine during gestation. To determine if the animals differed in impulse control, they performed four tests. For one of the tests, the researchers gave the animals the choice between pushing a lever that delivered a single banana pellet reward immediately or a lever that delivered several banana pellets, but required the animals to wait up to five minutes before the reward was delivered.

"That's where we saw very large differences between the groups," Hamilton said. "The males who were exposed to cocaine in-utero had no patience or impulse control whatsoever."
Those monkeys were less willing to wait for a larger food reward and preferred the immediately available, though much smaller, reward, indicating they were more impulsive than the adult male monkeys who had never been exposed to cocaine. There was, however, no difference in the preference of female monkeys prenatally exposed to cocaine and those never exposed to the drug.

After all of the impulsivity tests were administered, the researchers ranked each monkey from least to most impulsive and compared their average impulsivity score across the four tests. The researcher found that the male, but not female, monkeys prenatally exposed to cocaine were more impulsive overall compared to control monkeys who weren't exposed.