Extent of Criminal Liability for Person with Brain Injury

Let’s say we have a guy who suffered a closed head injury some years ago such that he’s recovered as much from it as he is likely to. A lingering effect of his injury he is that he now longer appreciates the consequences of his actions - he can’t see that a particular action might lead to punishment. But, his injury did leave mnay other functions intact - he can still set in motion a complex series of events and follow them to their conclusion.
So, let’s assume that he commits a crime that requires some preparation - let’s make it document intensive. He’ll need to tell different things to different people for his scheme to work.

Unfortunately for him, he pushes the ruse one step too far and is caught. If we go back to the beginning idea that he couldn’t appreciate the risk of punishment when he set his crime into motion, do we consider this disability when deciding how and whether to punish him?

I think that he should still be punished. His inability to appreciate possible punishment doesn’t mean that he can’t know what he set out to do was wrong. I don’t beleive the scenario I write suggests that he didn’t intend his actions, although there is room to argue that he didn’t intend to commit a crime. I say his intent to ommit the act should override any subjective belief as to whether it he thought he was committing a crime.

So, what to debate? I’d like thoughts on whether and to what extent a head injury should be a factor in deciding criminal liability. I’d like to see if the person in the scenario I wrote should get some slack, because my first answer is that he shouldn’t.

Interesting question.

The only defense for people with brain injuries is the insanity defense. I did see a television show on the brain which discussed a person with a brain chemistry imbalance that was treatable and was acquitted on the insanity defense for an assault and battery charge.

The M’Naghten rule governs the insanity defense, and to meet it the defense has to show at least a reasonable doubt whether:

  1. the defendant was laboring under such a defect of reason from disease of the mind as not to know the nature and quality of the act he was doing, or

  2. the defendant did not know that what he was doing was wrong.

Obviously 1 does not apply in your case; the guy has carried out a complex plan where one event is expected to lead to another, so he did understand what kind of acts he was doing or planning to do.

As you say, the fact that the defendant doesn’t know he will be punished doesn’t mean that he is unaware his actions are wrong or that he is incapable of distinguishing between right and wrong. So in my view, the facts you gave are not enough to meet the M’Naghten rule, and the guy should be convicted.

Danimal is dead on, but allow me to pontificate. One of the purposes of criminal penalty is to deter future crime, but that does not mean that one is allowed to commit crime if a person is unaware of or immune from punishment. One should not commit crime because it is the wrong thing to do, even if you can get away with it, and that is the only question asked when determining criminal intent.


In “The Man who Mistook his Wife for a Hat” the case is discussed of a man who killed his girlfriend while drunk. He was so drunk that he could not remember it happening. Because he could not remember he was declared Not Guilty by reson of insanity and committed.

After several years where it was obvious that he was not violent when sober, he was allowed priviledges to get out of the hospital once in a while. He took up his favorite hobby, bike riding.

One day he got hit by a car. As a result of the head trauma he could now remember the murder. He immediately became suicidal because of the guilt.

While not directly involving the OP, I just wanted to point out that it is not as far fetched as it seems. (This would make a good movie, BTW)


Au contraire. This may be the rule in your jurisdiction, but it ain’t the rule in mine, nor do I believe it is the rule at the Federal level.

A defendant suffering from a brain disorder/injury or any other condition impairing his cognitive abilities may raise a defense of “diminished capacity” to attack the mens rea element of a crime. In my jurisdiction, a diminished capacity defense may be raised for “any mental disorder not amounting to insanity.” However, in my state (as, I believe, in the Federal system), a diminished capacity defense may only be raised to defend against a crime requiring specific intent as a mens rea.

I think the OP’er’s question actually goes to mens rea – that is, what must you intend in order to be held criminally liable? As noted above, in my jurisdiction, as in the Federal jurisdiction, a defendant may plead diminished capacity to defend against a crime requiring a specific intent – like, say, premeditated murder (which requires premeditation, which can be disproven by showing diminished capacity).

So the answer to your question may turn on what particular crime the person was trying to accomplish and the type of intent (specific or general) necessary to prove that crime.

Most of the people on death row are psychopaths… they reckon now ( with brain scanning stuff ) that part of their brains just doesn’t work.

You could argue these people should be in a hospital for the criminally insane.

Well, I should have mentioned that IANAL. For all I know, there may be a “diminished capacity” defense in my jurisdiction too.

But my understanding from SDStaff Jill’s column was that “diminished capacity” is not a complete defense like insanity, because proving diminished capacity simply means proving oneself incapable of premeditation. And while there are acts that are only criminal when committed knowingly, I don’t know of any acts that are criminal only when committed with premeditation. Certainly premeditation is not necessarily required for mens rea. You can intend to do something wrong or unlawful even if you are doing it on the spur of the moment.

Correct. Mens rea isn’t eliminated because you acted on the spur of the moment. It can be pretty much instantaneous - if you are walking down the street and suddenly decide that you can’t make it home, and take a leak on the street, you had the mens rea to commit the crime of public indecency, even if you hadn’t planned to whip it out when you first started walking home.
There are indeed very few acts that are criminal without mens rea. But mens rea and premeditation are two very different things. Off the top of my head, premeditation is only important in determining what level of crime, not whether a crime was commited. Murder v. manslaughter comes to mind.


Thanks for your replies.
I think I’m trying to ask a two part question, it seems.
First, would be escaping liability altogether. Jodi, I don’t know whether diminished capacity exists in this jurisdiction, I’ll need to look into it. A message board that assigns homework… For the purposes of this discussion, the crime is fraud. We’ll assume the guy told a lie to get something that he wasn’t entitled to have.
Second, should the guy’s punishment be in any way reduced?
Third, Hi Opal!
Danimal, thanks for saving this thread, it was slipping down the page quickly.

Whether he gets jail time or not, he will almost certainly be locked away somewhere. In the situation you describe, anyone who just cannot appreciate the consequences of their actions can’t function in society. He’ll walk down the street slapping women on the ass because, well, what does he care? He could drive 100 MPH in a residential neighborhood since he’s not worried about what happens to him. He could jump off a cliff because he believes the laws of gravity don’t really apply to him.
This guy could cause harm to himself or to others with no concern or remorse. He would, or should, be put away.

SuaSponte, there are some jurisdictions, I believe, who accept spur of the moment premeditation. So if you’re holding a gun with absolutely no desire to fire it and then, for whatever reason, you do, the court will accept that split second before you fired it as premeditation. No word, though, on whether they consider the penis to be a type of gun or premeditation as an element of urinating in public. So maybe it doesn’t apply.

DANIMAL, I was not aware we were discussing “complete” defenses. It did not appear that way from either the OP or your response. She asked, “whether and to what extent a head injury should be a factor in deciding criminal liability.” You answered “The only defense for people with brain injuries is the insanity defense.” In the context of the question she asked, that’s just not right.

Well, no. I mean, yes, in that case, because the mens rea element to be challenged was premeditation. But that doesn’t mean diminished capacity cannot be used to challenge other types of mens rea. In other words, diminished capacity isn’t necessarily tied [ijust* to premeditation.

At least insofar as my jurisdiction is concerned, diminished capacity may be a defense to any crime with a mens rea, not just premeditation, including those where the mens rea is merely “knowingly.” The only time it is not at least a possible defense is if there is no mens rea element to the crime. (And also those cases where it has been statutorily outlawed, such as voluntary intoxication which, while obviously diminishing your capacity, by law will not provide a basis for a defense of “diminished capacity.”)

Here’s an example: In my state, you can be charged with first degree murder, made first degree because it was knowing and malicious (Case A). (Note that premeditation is not required.) You can also be charged with first degree murder, made first degree because of you manifested extreme indifference to human life (Case B). In the courts here, diminished capacity is a defense to Case A because it goes to a lack of the required mens rea. It is not a defense to Case B because Case B does not have an element of mens rea in the first place, so there is nothing to be attacked. Now, I do not say this is the law in every jurisdiction, but it is the law in mine.

Please continue to participate in these legal discussions; you appear to have a pretty good hold on the issues and a non-lawyer is a breath of fresh air. But beware giving blanket “yes” or “no” answers to legal questions; one of the first things we were taught in law school is that the only truly right answer to any legal question is “it depends.” :slight_smile:

ROBB, you appear to be asking whether a person should be held criminally liable for his actions when the actions are voluntary, but the person does not appreciate that they are criminal (or, as you put it, “can’t see that a particular action would lead to punishment”). I hope I haven’t over-simplified it. Is that your question? I will post my answer, but I want to be sure I’m answering the right question first.

I said:

This is overly-broad. To clarify, my jurisdiction holds that diminished capacity may be raised as a defense to any crime requiring specific intent.

You are evidently correct. I thought a “defense” was anything that legally excused an act, but looking at my Black’s I see it only has to make a charge untenable. So I concede this point.

OK. If I’m following you, in your jurisdiction, “diminished capacity” means the inability, by reason of some mental disorder or defect, to have the mens rea. But mens rea varies from crime to crime, in some cases just being “knowingly,” in other cases including “specific intent,” and in still other cases including “premeditation.” So a mental defect that might constitute “diminished capacity” for one crime might not constitute “diminished capacity” for another crime which requires a different kind of mens rea, or which doesn’t require mens rea at all. Is that right?

But I don’t grasp the distinction between a mental inability to commit an act knowingly (i.e. with mens rea), and the first element of the M’Naghten rule, “not to know the nature and quality of the act.” Aren’t both just different ways of saying, “Because of my mental defect, I didn’t know what I was doing?”

In any event, in Robb’s example, the guy knowingly commits the act, premeditates it, and has specific intent to do it, right? He knows he’s telling a lie, knows that it will get him something that he’s not entitled to, knows that the person he lies to will believe him, and knows that the law forbids him to do this. The only thing he doesn’t know is that he can be punished for it. So I don’t see how he can avail himself of the diminished capacity defense?


Close. “Diminished capacity” simply means that your mental capacity is diminished, whether since birth or by defect or injury or circumstance. The issue of whether that diminishment will mean you didn’t have the necessary mens rea for a particular crime obviously depends on the facts of each particular case. So you can’t define “diminished capacity” as “an inability to form the requisite mens rea,” because your capacity may well be diminished but still not prevent you from having the requisite mens rea.

Right. The difference between doing something “knowingly” or “maliciously,” for example. If your capacity is diminished in such a way that you cannot or do not act with malice, it might excuse the latter but not the former.

Sort of, but the M’Naghten rule is, as you know, an insanity defense. As my jurisdiction puts it, it is a defense for “for persons who have lost contact with reality so completely that they are beyond any of the influences of the criminal law.” In other words, the M’Naghten test is sometimes reworded as “Did the Defendant know what he was doing?” and “Did the Defendant know that what he was doing was wrong?” By “know what he was doing,” I mean either understand the nature of the act itself (crazy person fires a gun, thinking she is pointing a stick) or the nature of the consequence (crazy person fires a gun at a person, thinking she is firing it at a deer). While you are correct in noting some overlap (especially in the case of those whose mental defect manifests as insanity or something very like insanity), the M’Naughten rule cannot be a defense for those who are obviously not insane – like the mentally handicapped.

Actually, it isn’t clear if he understands that the law forbids him to do it – i.e., that the act is illegal. That’s what I’ve asked ROBB to clarify.

It’s a tough sell. The argument you would make is that while the actions were intentional, the diminished capacity meant he could not appreciate the criminality of his actions. (I think the argument that he just didn’t think he’d get caught is a NO sell.) This devolves back to “did he know it was wrong?” The problem here is that while the M’Naghten rule allows you to avoid criminal liability if you didn’t appreciate your acts were wrong, there is not to my knowledge the same rule regarding diminished capacity. But I would certainly make that argument by analogy. Whether it would be successful or not . . . I really don’t know. As some others may know, I don’t practice criminal law, though I there are one or two lawyers on the boards who either did or still do. Maybe they would have a better and more satisfactory answer?

No, he’s not. M’Naghten is an archaic case, and the insanity and diminished capacity defenses are a lot broader than that these days. Surely y’all haven’t forgotten the (successful) Twinkie Defense?

Um, KELLS, the Twinkie defense is the case discussed in JILLGAT’s piece, in the column linked above.

And the M’Naghten rule remains good law in a number of state that have codified it in statute, including mine. The insanity defense is therefore extremely difficult to prove, much more so than diminished capacity – though, as both DANIMAL and SUA pointed out, it does provide a complete defense, whereas diminished capacity often only results in a lesser sentence, after conviction for a lesser crime.

It’s amazing how seldom this sort of issue came up in the day-to-day life of a public defender. :slight_smile:

Still, I’ll offer my reaction: as Jodi has suggested, diminished capacity may vitiate the intent portion of a specific-intent crime. There is a rebuttable presumption that a person intends the ordinary consequences of his actions, and offering the affirmative defense of dimished capacity can rebut that presumption.

Still, if the key is simply that the actor didn’t realize he’d get caught, that’s irrelevant. As long as he knew his actions were proscribed by the law, he’s got the necessary mens rea; as long as he did the dirty deed, he’s got the actus reus.

  • Rick

Well, Danimal wasn’t dead on when he suggested that M’Naghten was the rule everywhere - but it’s still the rule in plenty of places. It is not, as you suggest, archiac, if by that you mean it’s no longer good law anywhere.

  • Rick

Jodi, I believe you got the question I wanted here:

Then, if we decide that he is criminally liable, should he be given any “credit” for his injury in assessing his punishment?

Well, ROBB, I think BRICKER sort of answered this. Failure to appreciate the criminality of one’s own actions is not a defense – there’s no defense of “I didn’t know it was illegal.” So it’s unlikely to offer a defense to the brain-injured plotter.

However, it probably would be taken into account as a mitigating factor when imposing punishment. A person who didn’t mean to break the law (either because they didn’t know they were doing so or couldn’t appreciate that their actions were criminal) can reasonably expect a judge to take that into account when deciding on a punishment. But that’s a different issue than whether or not, under these facts, the injury would constitute a defense. I think the answer to that is “no,” it wouldn’t. He committed fraud. He had the necessary mind-set to do it (ie, he intended to commit the fraud). Therefore he is guilty of the crime of fraud. So, yeah, he probably gets a little “credit” for it when sentence is imposed (or, at least, I’d assume he would, though sentencing is discretionary in most cases, assuming the guidelines are met). But it wouldn’t be enough “credit” to constitute an actual defense.