Excuse: Intoxication

Intoxication is involuntary if the accused took the intoxicant without awareness of its intoxicating nature or if the consumption was coerced. A person claiming this affirmative defense generally must show both that the intoxication was involuntary and that it either: (1) negated the mens rea required for the offense; or (2) created a state of irrationality or loss of self-control similar to insanity.

Involuntary intoxication is most commonly claimed by individuals who take substances unaware that they may be intoxicating, either because they mistook the identity of the substance or its likely effects (Carter v. State, 710 So.2d 110 (Fla. Ct. App. 1998) (mistaking anti-depression drug for over-the-counter pain killer); People v. Scott, 194 Cal.Rptr. 633, 146 Cal.App.3d 823(1983) (unknowing ingestion of hallucinogen in punch at a party causing a psychotic episode two days later); City of Minneapolis v. Altimus, 238 N.W.2d 851 (Minn. 1976) (ignorance about effect of prescription drugs). On occasion the accused may claim pathological intoxication, a rare condition of extreme and unforeseen susceptibility to an intoxicant (Model Penal Code § 208(5)(c)). A defendant may also claim involuntary intoxication on the ground that the taking of the intoxicant was coerced by another.

Once involuntary intoxication is shown, the defendant may argue lack of mens rea due to intoxication. This argument may be used regardless of the form of mens rea. Under involuntary intoxication there is no distinction between general or specific intent and no recklessness exclusion under the Model Penal Code. On occasion, courts give the offense a broad interpretation to find a form of mens rea relevant to involuntary intoxication (as in Carter; knowing intoxication required for driving under the influence where involuntary intoxication was alleged).

The defendant may also argue that involuntary intoxication created a state of temporary insanity. In most jurisdictions, involuntary intoxication may substitute for the mental disease or disorder element of the insanity test. Then the accused must show a major deficit in rationality or in capacity for control, depending on the jurisdiction's test for insanity (Torres v. State, 585 S.W.2d 746 (Tex.Cr.App. 1979)).

Finally, a defendant who was involuntarily intoxicated may be able to argue that intoxication rendered him unconscious, thus negating proof of a voluntary act (R. v. Quick (1973) All E.R. 347). Generally this argument is not available for voluntary intoxication, as most courts hold the individual responsible for choosing to risk loss of consciousness (People v. Velez, 221 Cal.Rptr. 631 (Ct. App. 1985); but c.f. R. v. O'Connor).

Conceptually distinct from involuntary intoxication is what has been called "settled insanity," a severe mental disorder that may result from heavy drinking over a long period and that may produce psychosis. Legally this condition falls under insanity, for the person suffers from a long-standing mental disorder not dependent on actual intoxication. Also to be distinguished are those individuals with significant mental problems who become intoxicated; their criminal responsibility should be analyzed under the rules of either voluntary intoxication or insanity based on underlying mental illness.