Exposure to stress in adolescence increases the vulnerability and risk of suffering psychopathologies in adulthood, such as drug dependence, depression, anxiety or gambling, among others. Researchers from the Institute of Neurosciences of the Autonomous University of Barcelona (INc), led by Roser Nadal and Antonio Armario, studied the factors that reduce the impact of stress. The research, published in Scientific Reports, used three groups of male rats to measure this impact. They found that exerting control over the source of stress diminishes its impact and could reduce the risk of developing mental disorders later.
One of the three groups of rats received several stress sessions during adolescence, which they could control (stop or prevent) by performing certain behavior. The second group received exactly the same amount of stress as the first group but their behavior had no consequence (uncontrollable stress). And finally, the third group acted as control and did not receive stress sessions.
During exposure to stress, the researchers quantified their intensity by measuring endocrine activation through the activity of the hypothalamic-pituitary-adrenal (HPA) axis. In the adult stage several experiments were carried out measuring various cognitive variables and the expression of type 2 dopamine receptors in the dorsal striatum, an important brain area for the measured behaviors.
The results indicated that the HPA activation induced by controllable and uncontrollable stress was the same in the first exposure session. However, after repeated sessions, the group able to control stress showed an attenuated response.
In the adult stage, animals that had been exposed to uncontrollable stress during their adolescence developed an increase in motor impulsivity and a decrease in cognitive flexibility, effects that were not evident in those animals subjected to controllable stress.
Preventive implications
In other aspects (attention and cognitive impulsivity) no impact of stress was observed. In parallel, the behavioral effects of uncontrollable stress were associated with an increase in the number of type 2 dopamine receptors in the dorsomedial striatum (but not in other subdivisions), a structure involved in impulsivity and cognitive inflexibility.
“Although exposure to stress situations exerts short and long term negative effects on behavior and physiology, there are several factors that could mitigate its impact. We have observed that one of these factors is the possibility of exercising control over the source of stress,” says Roser Nadal.
The work has several preventive implications, suggesting that strategies aimed at increasing the perception of controllability of stress during adolescence could mitigate the negative impact of stressful experiences in adulthood and reduce vulnerability to some psychopathologies.
Source: SINC
