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 Kansas, voluntary intoxication is generally not a defense to criminal charges. Kansas law holds that voluntary intoxication does not excuse criminal conduct or negate the requisite mental state necessary to commit a crime. However, involuntary intoxication may serve as a defense if it can be shown that the defendant was incapable of understanding what they were doing or that it was wrong due to the intoxication. This is because involuntary intoxication can negate the mental state required for a crime, as the defendant did not choose to become intoxicated. The specific statutes governing these defenses can be found in the Kansas Statutes Annotated (K.S.A.), particularly within the criminal code. Whether intoxication was voluntary or involuntary and its impact on the defendant's mental state is typically a question of fact for the jury to determine during a trial.