Intoxication Defense

The intoxication defense distinguishes between voluntary and involuntary intoxication, applying different rules to each. Voluntary intoxication, where the defendant knowingly consumed alcohol or drugs, is available only as a defense to specific intent crimes. It may negate the mens rea element by showing the defendant was so intoxicated that they could not form the specific intent required for the offense. However, voluntary intoxication is never a defense to general intent crimes, crimes requiring recklessness or negligence, or strict liability offenses.

Under the Model Penal Code, voluntary intoxication can negate purpose or knowledge but cannot negate recklessness. A defendant who is unaware of a risk due to voluntary intoxication is treated as if they were aware of the risk, because the MPC considers self-induced intoxication itself as reckless behavior. This effectively means voluntary intoxication can reduce a first-degree murder charge (requiring premeditation) to second-degree murder but cannot provide a complete defense to any crime requiring recklessness.

Involuntary intoxication receives much more favorable treatment. It occurs when the defendant unknowingly ingested an intoxicating substance, was forced to consume it, had an unexpected reaction to prescribed medication, or became intoxicated through pathological causes. Involuntary intoxication is treated like the insanity defense: if the intoxication rendered the defendant unable to understand the nature of their actions or to distinguish right from wrong, it is a complete defense to any crime. The distinction between voluntary and involuntary intoxication is therefore critical and often dispositive on the exam.