Intoxication due to a defendant’s voluntary consumption of drugs or alcohol isn’t usually a defense to criminal charges—but if the intoxication was involuntary, it may be a defense on the basis that the defendant did not understand what he was doing or that what he was doing was wrong. And some states allow a defendant to assert a defense that his voluntary intoxication prevented him from forming the specific intent to commit the crime (attempted murder, for example). But this is a question of fact that the jury will usually determine.

The availability and definition of any defense to criminal charges based on the defendant’s voluntary or involuntary intoxication is usually located in a state’s statutes—often in the penal or criminal code.

In Arizona, voluntary intoxication is generally not a defense to criminal charges. According to Arizona Revised Statutes (ARS) § 13-503, voluntary intoxication is not a defense for any criminal act or requisite state of mind. This means that a defendant cannot argue that because they were voluntarily intoxicated, they were unable to form the specific intent necessary to commit a crime. However, involuntary intoxication is treated differently. If a defendant was involuntarily intoxicated—meaning they were coerced into consuming drugs or alcohol, or did so unknowingly—they may have a defense if the intoxication left them incapable of understanding what they were doing or that it was wrong. The distinction between voluntary and involuntary intoxication is significant in Arizona law, and whether intoxication can be used as a defense is a question of fact that a jury may determine, particularly in cases of involuntary intoxication.