Scientific research seems to disagree
Here is what the best scientific studies show about behavior effects of steroid use:
Case reports and small studies indicate that anabolic steroids, particularly in high doses, increase irritability and aggression. Some steroid abusers report that they have committed aggressive acts, such as physical fighting, committing armed robbery, or using force to obtain something. Some abusers also report that they have committed property crimes, such as stealing from a store, damaging or destroying others' property, or breaking into a house or a building. Abusers who have committed aggressive acts or property crimes generally report that they engage in these behaviors more often when they take steroids than when they are drug-free.
Some researchers have suggested that steroid abusers may commit aggressive acts and property crimes not because of steroids' direct effects on the brain but because the abusers have been affected by extensive media attention to the link between steroids and aggression. According to this theory, the abusers are using this possible link as an excuse to commit aggressive acts and property crimes.
One way to distinguish between these two possibilities is to administer either high steroid doses or placebo for days or weeks to human volunteers and then ask 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; but in one study, the drugs did not have that effect. One possible explanation, according to researchers, is that some but not all anabolic steroids increase irritability and aggression.
Anabolic steroids have been reported also to cause other behavioral effects, including euphoria, increased energy, sexual arousal, mood swings, distractibility, forgetfulness, and confusion. In the studies in which researchers administered high steroid doses to volunteers, a minority of the volunteers developed behavioral symptoms that were so extreme as to disrupt their ability to function in their jobs or in society. In a few cases, the volunteers' behavior presented a threat to themselves and others.
In summary, the extent to which steroid abuse contributes to violence and behavioral disorders is unknown. As with the health complications of steroid abuse, the prevalence of extreme cases of violence and behavioral disorders seems to be low, but it may be underreported or underrecognized.
Now can we go back to shitting on the Yankees?