Prenatal psychological stress causes higher emotionality, depression-like behavior, and elevated activity in the hypothalamo-pituitary-adrenal axis

In humans, stressful events during pregnancy may raise the risk of psychiatric disorders in offspring, and studies with rodents have found that physical prenatal stress can cause changes in the physiology, neurobiology, and behavior of offspring. In the present study, we examined whether psychological prenatal stress with little physical stress could cause changes in the neurobiology and behavior of offspring in Sprague–Dawley rats, as physical prenatal stress did. Dams received psychological stress by observing a rat being electrically shocked behind a transparent wall in the social communication box during the last trimester of gestation but were not exposed to any physical stress. Male offspring from the dams exposed to psychological stress showed enhanced emotionality in an open field test, depression-like behavior in a forced swim test, and enhanced activity in the hypothalamo-pituitary-adrenal axis, compared with rats from untreated dams. However, the prenatally stressed rats showed intact ability to acquire context conditioning. This is the first report that psychological prenatal stress in the communication box can cause changes in the neurobiology and behavior of offspring in rodents.