Inhibitory motor control at five years as a function of prenatal cocaine exposure.

This study examined children's (n = 140, age 5 years) ability to inhibit a motor response as a function of prenatal cocaine exposure. We hypothesized that cocaine-exposed children would perform worse than unexposed children on the Contrary Tapping task. Results indicated that cocaine exposure, high environmental risk, male gender, and low child IQ each were related to poorer inhibitory control. An interaction indicated that cocaine effects were specific to children who lived in relatively low-risk environments. Cocaine-exposed children made an error sooner than unexposed children in low-risk environments but in the same trial as both exposed and unexposed children living in high-risk environments. Potential underlying mechanisms and the importance of examining cocaine exposure effects in the context of children's existing environment are discussed.