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 Oregon, voluntary intoxication is generally not a defense to criminal charges. This means that a defendant cannot claim they were unable to form the intent to commit a crime due to being under the influence of drugs or alcohol. However, there are exceptions where involuntary intoxication may be considered a defense. Involuntary intoxication can occur if the defendant was coerced into consuming the substance or was unaware they were consuming it, and as a result, could not understand the nature or wrongfulness of their actions. The distinction between voluntary and involuntary intoxication is significant, and whether intoxication can be used as a defense is a factual determination typically made by a jury. The specifics of these defenses and their applications are outlined in Oregon's criminal statutes.