Steroids trigger long lasting aggression in teens

According to a U.S. study steroids may have a lasting effect on teenagers' brains, and could even flip the adolescent brain's switch for aggression which may last for at least two years.

The U.S. researchers also suggest anabolic steroids can cause permanent brain changes.

The study however was based on results seen in hamsters and some experts say on that basis it is impossible to estimate the length of effect in humans.

Neuroscientists are deeply concerned about the rising adolescent abuse of anabolic-androgenic steroids (AASs), given the National Institute on Drug Abuse's estimate that nearly half a million 8th to 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, it is known that long-term steroid use can cause mood swings, hallucinations and paranoia, liver damage and high blood pressure, as well as increased risk of heart disease, stroke and some types of cancer.

Coming off steroids can also lead to depression.

The researchers at Northeastern University, Boston, examined the behaviour of adolescent hamsters when another hamster was put into their cage.

It seems that hamsters naturally defend their territory by play-fighting, wrestling and nibbling, but hamsters injected with commonly used steroids, which were suspended in oil, became extremely aggressive.

According to the researchers even after the drug was withdrawn, the newly vicious hamsters attacked, bit and chased the intruders, and the level of aggressiveness was 10 times greater than that of other hamsters which were only injected with oil.

Apparently the effects lasted for almost two weeks, which is the equivalent of half their adolescence.

After this period, the animals reverted to their normal playful defensiveness, but postmortems on the hamsters found there had been also been changes in their brain activity.

While they were being given steroids, a part of their brains called the anterior hypothalamus, which regulates aggression and social behaviour, pumped out more of a neurotransmitter called vasopressin.

Their full-blown aggression which was clearly drug-induced lasted for nearly two weeks of withdrawal.

Three weeks after withdrawal, vasopressin levels had subsided in line with the aggressive behaviour.

Dr Richard Melloni, who led the research, said that because the part of the brain which his team studied is similar in rodents and humans, their findings are probably applicable to people.

Dr Melloni says because the developing brain is more adaptable and pliable, steroids could change the trajectory if administered during development.

He believes that people considering the use of such drugs should consider the long-term health risks and the serious potential for aggression and violence.

He hopes that adolescents don't take the ultimate recovery of the vasopressin system to mean it's OK to use the drugs.

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.

The researchers hope the findings could potentially hasten the development of treatments for aggressive behaviour, whether or not it has been caused by steroid abuse.

The study is published in the current edition of Behavioral Neuroscience, Vol. 120, No. 1.