I also have to object to your use of the word "evil" in regards PED use. I know what evil is. PED use doesn't come close to meeting the mark. Let's keep in mind that when we're talking about ballplayers using drugs, we're talking about off-label use of prescription drugs, or use of illegally purchased Schedule III drugs. While I hope not to disillusion anyone, our society wouldn't function without the former: Whether it be your nephew popping Adderall before taking the SAT, your lawyer snorting Ritalin to keep up as he plows through thousands of pages of documents in an all night billable session, your surgeon munching amphetamines while replacing your heart valve, or the hack journos you read doing all of the above as they try to clear their deadlines, using prescription drugs to do better at your job is right up there with driving at 70 on the list of shocking things Americans do. As to the latter, ballplayers using steroids are up there with club kids doing Special K and housewives popping barbiturates given to them by friends on the list of scallywags and ne'er-do-wells of modern civilization.
Scientists have attempted to test the association between anabolic steroids and aggression by administering high steroid doses or placebo for days or weeks to human volunteers and then asking the people to report on their behavioral symptoms. To date, four such studies have been conducted. In three, high steroid doses did produce greater feelings of irritability and aggression than did placebo, although the effects appear to be highly variable across individuals. In one study, the drugs did not have that effect. One possible explanation, according to the researchers, is that some but not all anabolic steroids increase irritability and aggression. Recent animal studies show an increase in aggression after steroid administration.