Anabolic/androgenic steroid abuse is suspected of producing direct damage to the heart muscle in some cases. Studies exposing heart cell cultures to AAS have reported reduced contractile activity, increased cell fragility, and reduced cellular (mitochondrial) activity, providing some support for a possible direct toxic effect to the heart muscle. 107 108 Furthermore, a number of case reports have found such pathologies as myocardial fibrosis (scar tissue buildup in the heart), myocardial inflammation (inflammation of heart tissue), cardiac steatosis (accumulation of triglycerides inside heart cells), and myocardial necrosis (death of heart tissue) in long- term steroid abusers. 109 110 111 112 A direct link between drug abuse and cardiac pathologies is assumed in these cases, but cannot be proven given the slow nature in which these cardiac pathologies develop, and the influence many other factors (such as diet, exercise, lifestyle, and genetics) can have on them. Individuals remain cautioned about the possibility of cardiac muscle damage with long-term steroid abuse.
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.