Abstract
Offspring of female rats treated early in gestation with chlorpromazine (CPZ) were tested at 30 days of age for seizure susceptibility and at 90 days of age for shock avoidance learning. Fostering procedures permitted separation of prenatal influences from postnatal rearing influences of drug treatment. Offspring of drug‐treated mothers had higher avoidance scores, higher intertrial activity levels, and greater seizure susceptibility than offspring of controls. Animals reared by previously treated mothers also had higher avoidance and greater seizure susceptibility. This postnatal effect depended on sex and was not accompanied by an overall increase in intertrial activity. Rearing by a previously drug‐treated mother was also found to modify the influence of neonatal stress on adult avoidance learning.