A video featuring a paladin named Leeroy Jenkins of the guild Pals for Life from the Laughing Skull Server became one of the first major World of Warcraft memes. In the video, a paladin foolishly runs into a nest of eggs which ends up killing his entire party in the Upper Black Rock Spire Rookery.
While neither drinking or the use of drugs are signs of an abusive personality, heavy drinking or drug abuse may be a warning sign and do increase the risks of abuse, especially violence, taking place. Often an abusive person will blame the drink for his/her abuse.
1 Substance abuse can look like uncontrollable use of a substance to a point that is physically dangerous, or frequent continued use over time. They may engage in risky behaviors as a result of the abuse.  Often, those with sociopathic tendencies grew up in a home or with a caretaker that also abused drugs or alcohol.