Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Animal models show that anabolic steroids flip the adolescent brain’s switch for aggression

27.02.2006


Hamsters with ’roid rage’ reveal that human teens may stay nasty for more than two years, with possible long-term brain impact



Anabolic steroids not only make teens more aggressive, but may keep them that way into young adulthood. The effect ultimately wears off but there may be other, lasting consequences for the developing brain. These findings, published in February’s Behavioral Neuroscience, also showed that aggression rose and fell in synch with neurotransmitter levels in the brain’s aggression control region. Behavioral Neuroscience is published by the American Psychological Association (APA).

Neuroscientists are deeply concerned about rising adolescent abuse of anabolic-androgenic steroids (AASs), given the National Institute on Drug Abuse’s estimate that nearly half a million eighth- and 10th-grade students abuse AASs each year. Not only do steroids set kids up for heavier use of steroids and other drugs later in life, but long-term users can suffer from mood swings, hallucinations and paranoia; liver damage; high blood pressure; as well as increased risk of heart disease, stroke and some types of cancer. Withdrawal often brings depression, and recent research suggests that some AASs may even be habit-forming.


Overseen by Richard Melloni Jr., PhD, of Northeastern University in Boston, the current study of 76 adolescent hamsters compared how individual hamsters behaved when another hamster was put into their cages. Normally mild-mannered hamsters still defend their turf, learning aggression during puberty by play-fighting, much like humans. Their roughhousing normally includes wrestling and nibbling – pretty tame stuff.

However, hamsters injected with commonly used steroids (suspended in oil) became extremely aggressive. Even after the drug was withdrawn, the newly vicious hamsters attacked, bit and chased the intruders. In fact, their aggressiveness measured ten times greater than that of control hamsters injected with oil only. Their full-blown aggression – clearly drug-induced -- lasted for nearly two weeks of withdrawal, the equivalent of half their adolescence. Eventually, the aggressiveness subsided; by three weeks of withdrawal, all the hamsters greeted intruders with normal, playful defensiveness.

Autopsy revealed that the outward aggressiveness correlated with inner changes in the brain. When the drugged hamsters were hostile hosts, a part of their brains called the anterior hypothalamus pumped out more of a neurotransmitter called vasopressin. By three weeks of withdrawal, vasopressin levels subsided in parallel with the aggressive behavior. The anterior hypothalamus regulates aggression and social behavior. Thus, vasopressin – already known to stimulate that area – appears to fuel the engine of aggression. And, says Melloni, "Steroids step on the gas for agression."

Thus, the neuroscientists conclude that the aggressiveness triggered by anabolic steroids, although reversible, may last long enough to create serious behavioral problems for adults. Because this part of the rodent and human nervous systems are similar, researchers generalize their findings to humans. As a result, Melloni and his colleagues speculate that anabolic steroids can dramatically shorten teenage fuses (not known for length under the best of circumstances) and make young people "pop off" for years, a danger to themselves and to others. Melloni and others researchers also are concerned that drug use during a critical window in brain development can change their wiring for good. He says, "Because the developing brain is more adaptable and pliable, steroids could change the trajectory if administered during development." His lab is releasing other new findings, as yet unpublished, that the serotonin system – implicated in depression – may never recover.

"If you hit the right areas of the brain at the right time, you make permanent changes," Melloni concludes from the converging evidence.

He hopes that adolescents don’t take the ultimate recovery of the vasopressin system to mean it’s OK to use the drugs. "It’s our hope that people considering the use of these drugs weigh the long-term health risks and the serious potential for aggression and violence. Muscle mass and medals aren’t worth the risk of hurting someone or landing in jail."

Finally, researchers such as Melloni hope these new insights can lead to treatments for aggressive behavior, with or without steroid abuse. "Linking aggression to fluctuations in vasopressin makes it an important neurotransmitter to target for pharmacotherapy," he says.

Pam Willenz | EurekAlert!
Further information:
http://www.apa.org

More articles from Studies and Analyses:

nachricht Smart Data Transformation – Surfing the Big Wave
02.12.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT

nachricht Climate change could outpace EPA Lake Champlain protections
18.11.2016 | University of Vermont

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>