Concept

Defining Intoxication

Intoxication

Defining Intoxication

The Model Penal Code's intoxication provision, § 2.08, gives its key terms fixed meanings in subsection (5), and those meanings govern the section "unless a different meaning plainly is required."¹ The definitions come before the rules here because every operative rule in § 2.08 depends on which kind of intoxication is in play. Subsection (1) makes intoxication a defense only when it negatives an element of the offense. Subsection (2) removes unawareness of a risk from the recklessness inquiry when the intoxication was self-induced. Subsection (4) creates an affirmative defense, one that can succeed even though the State has proved every element, for intoxication that is not self-induced or is pathological and that leaves the actor without substantial capacity to appreciate the criminality of the conduct or to conform it to the law.² A reader who skips the definitions cannot tell which of those subsections applies.

Subsection (5) defines three terms, and this section takes the first two. Intoxication is defined by its effect on the person. Self-induced intoxication is defined by what the actor knew and chose when the substance went in. Pathological intoxication, defined in § 2.08(5)(c), is taught later with the involuntary-intoxication defense that uses it. The self-induced definition carries the most weight, because the early common law refused relief when the offender's incapacity was his own act and folly, and the Code keeps that fault idea in a narrower, testable form. Intoxication counts as self-induced when the actor knowingly introduced the substance and knew or ought to have known its tendency to intoxicate, and the definition excepts substances taken on medical advice or in circumstances that would afford a defense to a charge of crime.³

The pair shows why classification has to come first. Identical impairment produces different legal consequences depending on how it came about, and the Code's vocabulary is how it sorts one situation from the other. On an exam, the first move is to classify the intoxication before choosing a rule, since a stem that says only that the defendant was drunk or high leaves the question of origin to the reader. The next two subsections take the definitions in order, beginning with what counts as intoxication at all and then turning to the knowledge test that makes it self-induced.

What Counts as Intoxication

The first definition in Model Penal Code § 2.08(5) settles whether the defendant was intoxicated at all, before any question about what the intoxication can accomplish. The Code defines intoxication as a disturbance of mental or physical capacities resulting from the introduction of substances into the body.⁵ The sentence has three working parts. There must be a disturbance of capacities, which may be mental (judgment, perception, the ability to form a purpose) or physical (coordination, balance, reaction time). The disturbance must result from something, so the cause matters. And the cause must be a substance introduced into the body, by whatever route it entered.

Because the definition names no particular substance, it covers alcohol, narcotics, inhalants, and prescription medication alike. It also names no measurable level. The question it asks is whether the person's capacities were disturbed, and a chemical concentration is at most evidence on that question. The reason for defining the term by its effect is that one framework can then govern every impairing substance. Had the Code tied intoxication to alcohol, it would have needed a separate rule for narcotics and another for medication, and two defendants with the same impairment could have been treated differently only because of what they swallowed. The Code instead leaves the question of origin to the next definition, self-induced intoxication, where the inquiry is what the actor knew and chose.

Hypothetical Illustration

Two defendants are each charged with assault, and each had impaired judgment and coordination at the time. The first defendant had taken a prescription sleep medication that left the defendant confused and unsteady. The second defendant had gone several days without sleep, with no substance of any kind taken. The first defendant's condition is a disturbance of capacities resulting from a substance introduced into the body, so it is intoxication under § 2.08(5)(a) even though no alcohol was involved. The second defendant's capacities were equally disturbed, but nothing was introduced into the body, so the condition falls outside § 2.08 altogether and any argument it supports must be made on other grounds. The one fact that moved the answer is whether a substance caused the disturbance.

Meeting this definition is only the first step, and it does not say whether the intoxication helps the defendant. The medication in the hypothetical qualifies as intoxication, yet whether it can negate an element, or support an affirmative defense, depends on how it came about and on what mental state the offense requires, which the following sections develop. The common mistake is to look for a legal threshold or a particular drug, and the definition contains no blood-alcohol level and names no particular substance. A stem that describes an impairing substance of any kind has therefore satisfied the definition, and the analysis moves on to classify its origin.⁶

Self-Induced Intoxication

Of the two definitions taken up in this part of the chapter, the one for self-induced intoxication does the sorting, because it decides which of the Code's intoxication rules a defendant may use. Under Model Penal Code § 2.08(5)(b), intoxication is self-induced when it is caused by substances that the actor knowingly introduces into the body, the tendency of which to cause intoxication the actor knows or ought to know, unless the actor introduces them pursuant to medical advice or under such circumstances as would afford a defense to a charge of crime.⁸ When the intoxication meets that definition, the defendant has two limited tools. It is a defense only if it negatives an element of the offense, and when recklessness is the element, unawareness of a risk that a sober person would have noticed is immaterial.⁹ When the intoxication does not meet the definition, the element-negating use remains available, and subsection (4) adds an affirmative defense for an actor who lacked substantial capacity to appreciate the criminality of the conduct or to conform it to the law.¹⁰ The self-induced label is therefore the gateway to the whole section.

Exam Analysis Steps

Because the definition joins two knowledge requirements to two exceptions, it is easiest to run as a sequence of questions, each of which must come out a particular way before the label attaches. The steps are these:

Ask whether the actor knowingly introduced the substance into the body, which requires awareness that a substance is being taken in.
Ask whether the actor knew or ought to have known that the substance tends to cause intoxication, a standard met by actual knowledge or by the warning that ordinary experience or a product label would have given.
Ask whether the actor took the substance pursuant to medical advice, since that exception removes the label even when the first two answers are yes.
Ask whether the substance went in under circumstances that would afford a defense to a charge of crime, such as a threat of the kind that supports duress, since that exception also removes the label.
Classify the intoxication as self-induced only when the first two answers are yes and neither exception applies.

The first two questions track the fault the Code is willing to hold against a drinker. The knowing-introduction requirement means the actor must have been aware of putting a substance into the body, so a person who swallows something without realizing it falls outside the definition. The second requirement asks what the actor knew or ought to have known about the substance's tendency, which makes the standard partly objective: actual knowledge satisfies it, and so does the warning that common experience or a label would have given a reasonable person. That objective edge matters because the fault lies in running a foreseeable risk, and an actor who ignores an obvious or printed warning has run it just as surely as one who understood it perfectly. Together the two requirements isolate a genuine choice, which is why the resulting incapacity is treated as the actor's own responsibility.

The definition never asks whether the actor meant to become intoxicated, and a reader who adds that requirement will misclassify most drinkers. A person who sets out to have two beers and ends the evening impaired knowingly introduced a substance whose tendency was familiar, so the intoxication is self-induced even though the plan was to stay sober. The reason for leaving purpose out is practical as well as principled. A purpose requirement would turn on a state of mind that only the defendant can describe, and it would hand the benefit to the drinker who insists that every drink was meant to be the last. Knowledge of the act and of its tendency is enough, and the actor need not have intended to become intoxicated.

Hypothetical Illustration

A defendant drinks several strong beers at a bar, knowing that alcohol impairs judgment, and had meant to stop after one. The intoxication is self-induced, because the defendant knowingly drank a substance whose tendency to intoxicate was known, and the intention to stay sober does not change that. A guest at a party, by contrast, takes a cup of punch that another guest has secretly spiked, with nothing in its taste or smell to suggest alcohol. The guest drank the punch knowingly but had no reason to know it would intoxicate, so the intoxication is not self-induced, and the same result follows if the point is framed as the guest never having knowingly introduced an intoxicating substance. The one fact that moved the answer is what each actor knew about the tendency of what went down.

The classification then controls what each defendant can do. The bar patron's impairment helps only if it negatives an element under § 2.08(1), and if the charge rests on recklessness, the patron's failure to notice a risk is treated as immaterial under § 2.08(2).¹¹ The guest's impairment can likewise negate an element, and if it left the guest without substantial capacity to appreciate the criminality of the conduct or to conform it to the law, it supports the affirmative defense of subsection (4), which operates even when the State has proved every element.¹²

Two exceptions remove the label even when both knowledge requirements are met: a substance taken pursuant to medical advice, and a substance taken under circumstances that would afford a defense to a charge of crime.¹³ Each corresponds to a situation in which the choice the definition looks for is missing or blameless. An actor who follows a physician's directions is doing what the law would want a patient to do, so holding the resulting impairment against that actor would penalize compliance. An actor who takes a substance under compulsion has not chosen the intoxication in any sense that justifies blame. Both exceptions return in the later treatment of involuntary intoxication, where they feed the affirmative defense of subsection (4); here the point is that they sit inside the definition and therefore decide the classification before any other rule is chosen.

On an exam stem that reports only that the defendant was drunk or high, the analysis asks what the defendant knew about the substance and what it does, and then checks for medical advice or compulsion. A defendant who drank or used knowingly receives only the narrow rules, while a defendant who was tricked, compelled, or following a physician's directions keeps the broader set.