Stressful events early in a person's life, such as neglect or abuse, can have psychological impacts into adulthood. New research shows that these effects may persist in their children and even their grandchildren.
Larry Feig and Lorena Saavedra-Rodríguez, biochemists at the Tufts University School of Medicine, caused chronic social stress in adolescent mice by regularly relocating them to new cages over the course of seven weeks. The researchers then tested these stressed mice in adulthood using a series of standard laboratory measures for rodent anxiety, such as how long the mice spent in open areas of a maze and how frequently they approached mice they had never met before.
Female mice showed more anxious behaviors compared with control animals, whereas the males did not. Both sexes' offspring displayed more anxious behaviors, however, and the males who had been stressed as adolescents even transmitted these behavior patterns to their female grandchildren and great-grandchildren.
These results, they say, confirm previous studies that females seem to be at higher risk for anxiety, which could be the result of a variety of social or biochemical factors. “Males and females might have the same abnormality at the molecular level,” Feig notes, “[but] as males, it doesn't really affect their behavior.”
Although Feig does not yet know how the males transmit vulnerability to anxiety—he suspects biochemical changes in sperm—he believes that the effects will most likely be more muted in humans. The mice were raised in simple cages with a limited number of environmental influences. Humans, of course, have a much richer environment, along with the ability to learn new coping skills.