Yes, "'roid rage" is real. Researchers have documented several cases of violent, aggressive behavior associated with anabolic-androgenic steroid (AAS) use, and many of those reports involved men with no prior history of violence, according to a paper published in 2010 in the journal Hormones and Behavior. However, the likelihood that those muscle-building, masculinizing hormones could make a man kill is difficult for researchers to estimate.
First, there’s the issue of dosage. Researchers can’t ethically administer high doses of AAS to test subjects because of the drugs' known adverse medical effects, including irregular heartbeats, and infertility. Men who have taken up to 300 milligrams per week in a laboratory setting have shown few psychological changes. (Normal males produce 50 to 75 milligrams of testosterone per week naturally.) However, athletes who regularly use AAS for the muscle-building, performance-enhancing benefits have reported taking doses equivalent to 1,000 to 5,000 milligrams per week, according to the paper cited above. Studies that have tested doses up to 600 miligrams per week have shown that higher doses of AAS are associated with increased aggression.
Observational studies in which researchers have monitored people on steroids for aggressive behavior are equivocal. Some studies have shown that steroid users are more irritable and ill-tempered than non-users, but those changes in mood were not linked to physical violence. And while researchers have linked steroids to violent crimes, including shootings and stabbings, "'roid rage," to our knowledge, has never been used successfully by the defense in a murder trial. And there have been plenty of murder trials in which the defendant claimed to be, or was accused of being, under the influence of AAS at the time of the murder.
In 1993, bodybuilder Gordon Kimbrough stabbed and strangled his girlfriend while on steroids. His lawyers tried to argue that he acted in a fit of uncontrollable rage, which would give him a manslaughter conviction and a maximum of 13 years in prison. The jury found him guilty of first-degree murder and Kimbrough received the maximum sentence of 27 years to life. So if history serves as a guide, don’t look for Oscar Pistorious to blame the killing of his girlfriend on the 'roids.
Want to read more stories about men snapping on steroids? Popcrunch.com put together a list of “6 Roid Rage Fueled Murders.” In 1998, Sports Illustrated published an in-depth look into the bodybuilding subculture and murderous muscle men: "The Muscle Murders."