Several case reports and survey studies have indicated that abuse of anabolic androgenic steroids (AAS) often leads to increased aggressiveness and feelings of hostility that may occasionally trigger violent behaviour. Other observations indicate that many users of AAS also abuse alcohol and/or various illegal substances. Since substance abuse is a well-known risk factor for violent behaviour, it could be that violence committed by AAS users might, at least in many cases, actually be caused by abuse of other drugs. In order to examine this possibility further here, the criminal histories (in terms of incidences of convictions) of deceased users of AAS with (AASpos-subst.pos) and without (AASpos-subst.neg) signs of abuse of other illegal substances were compared to the corresponding histories of deceased users of illicit substances testing negatively for AAS (subst.pos-AASneg) at the time of autopsy. The risk of being convicted for a crime against property was significantly higher in the subst.pos-AASneg group than in either the AASpos-subst.neg or AASpos-subst.pos groups (RR=0.048 versus 0.408). At the same time, the risk of being convicted for a crime of violence was at least as high for the two AAS-positive groups as for the AAS-negative group. Furthermore, when compared with the first 3 years after the first criminal conviction, a pronounced increase in the proportion of incidence of violent crimes and a marked reduction in the proportion of incidence of crime against property was observed during the 3-year period immediately preceding death only among the AASpos-subst.neg subjects. In conclusion, the incidence of violent crime among users of AAS without signs of other drug abuse was comparable to the corresponding incidences for drug addicts without AAS use. This observation suggests that the violent criminality observed among AAS users is not confounded in any systematic fashion by abuse of other drugs. The findings also indicate that use of AAS in certain predisposed individuals might cause a high rate of violent crimes, especially if the use of AAS is combined with the use of other illegal substances.