Information from Lay-Language Summaries is Embargoed Until the Conclusion of the Scientific Presentation
754—Aggression and Defensive Behavior
Wednesday, November 13, 2013, 8:00 am - 12:00 noon
754.01: Aggression and anxiety during exposure predict behavioral responding during withdrawal from anabolic-androgenic steroid adolescent Syrian hamsters
Location: Halls B-H
">*L. A. RICCI, T. R. MORRISON, R. H. MELLONI, Jr.; Dept of Psych, Northeastern Univ., BOSTON, MA
Abstract Body: In the U.S. and worldwide anabolic-androgenic steroid (AAS) abuse remains high in the adolescent population. This is concerning given that AAS use is associated with a higher incidence of aggressive behavior during exposure (e.g., Pope et al., 1994, 1996), and anxiety during withdrawal (e.g., Pagonis et al., 2006). Using pubertal Syrian hamsters (Mesocricetus auratus) we investigated the hypothesis that an inverse behavioral relationship exists between adolescent AAS-induced alterations in aggression and anxiety during adolescent exposure and across withdrawal. First we examined whether adolescent AAS use altered anxiety-like responding during AAS exposure or only during AAS withdrawal, as we have observed previously using the Elevated Plus Maze (EPM) and Dark Light (DL) tests. In the EPM and DL tests, adolescent AAS exposure lead to significant increases in anxiety-like responding only during AAS withdrawal. Then, AAS exposed animals were separated into groups based on their aggressive response during the AAS exposure period and tested for anxiety during adolescent AAS exposure, and then for both aggression and anxiety during AAS withdrawal. Data were analyzed using a within subjects repeated measures analysis. Follow-up linear regression analyses revealed that the difference in aggressive responding between the AAS exposure and withdrawal periods was a significant predictor of differences in anxiety for both days of testing. Moreover, the combined data suggest that the decrease in aggressive behavior from exposure to withdrawal predicts an increase in anxiety-like responding within these same animals during this time span. Together these findings indicate that early AAS exposure has potent aggression- and anxiety- eliciting effects and that these behavioral changes occur alongside a predictive relationship that exists between these two behaviors over time.
Lay Language Summary: Data from our lab indicates that during puberty, steroid-induced aggressive behavior can be used to estimate whether anxiety will develop during steroid withdrawal. This connection between aggression and anxiety is interesting because it may suggest that the brain structures that control aggressive behavior are shared with those that regulate anxiety. Various neurobiological development studies indicate that the effects of drugs on the adolescent brain are typically different than the effects they have on the adult brain. Not surprisingly, both human and animal studies have furthered this notion showing that adolescent use of certain drugs may be responsible for a multitude of psychological conditions that can only be detected in adulthood when prevention of abuse is far too late. This phenomenon is especially relevant to steroids since steroid exposure during adolescence can result in brain alterations that increase aggressive behaviors during early adulthood. Steroid use has also been linked to anxiety. For instance former steroid-users have a higher diagnosis rate of generalized anxiety disorder than current users or those that have never abused the drug. Moreover, animal studies have shown that aggression and anxiety appear to be linked as animals bred to have low levels of anxiety show high levels of aggression. The behavioral effects of steroid exposure are especially concerning given that an annual survey funded by the National Institute of Health and the National Institute on Drug Abuse found that nearly a half a million 8th-12th graders in the US have tried steroids in the past year. Worldwide, the use of steroids is a growing concern as the adolescent usage rate in Australia and parts of Europe is 4 to 6 times greater than the rate in the US. In our study we measured aggressive behavior and anxious behavior in male hamsters after they had been given steroids throughout adolescence. After 3 weeks of steroid withdrawal, we measured anxiety and aggression again. We found that aggressive animals administered steroids become less aggressive and more anxious during withdrawal from the drug. These results are notable considering that they show steroid abuse (specifically during adolescence) may alter brain structures that control anxiety long after steroid use has ended. From these results, we were able to develop a model that predicts anxiety during withdrawal from steroids. This model allows us to predict how anxious an animal will become during withdrawal, based upon the aggressive behaviors that are displayed during early adulthood while steroids are still circulating in the animal’s bloodstream. Considering the connection between aggression and anxiety, as well as the effects that steroid use has on the developing brain, our behavioral results suggest that similar brain circuitry may control steroid induced aggression and anxiety. More precisely, we believe that steroid use during adolescence alters brain structures that both enhance aggressive behavior and inhibit anxious behaviors. During withdrawal from steroids, these same circuits likely reverse function, which in turn reduces aggression while increasing anxiety. In future studies, we hope to exploit the relationship we have discovered between aggression and anxiety to identify the specific changes that take place in the brain which are necessary for aggression to disappear and anxiety to emerge during steroid withdrawal. This line of research is important considering the ever-increasing number of school-age children that are trying steroids, as well as individuals that have abused steroids in the past and are now well into withdrawal. And, although some decisions have consequences that last a lifetime, for some individuals, the results of our study could help guide the development of drugs that alleviate the long-lasting effects of experimental substance abuse that is common during youth.
Neuroscience 2013 (43rd annual meeting of the Society for Neuroscience)Exit