Would it not make a lot more sense for doctors to be the jury in insanity claims?

[Simple Linctus]

Would it not make a considerable deal more sense for doctors to be the jury for cases like this 'un:

Originally Posted by Telegraph

The jury took eight hours to reject her lawyer’s claims however that she was in a state of “psychiatric disturbance” and suffering insurmountable fear when the tragedy happened and therefore was not criminally responsible.

Surely said jury should be made up of doctors if its decision is to be accorded any respect?

(No comment on the merits of this verdict is intended by this post)

[kunilou]

The Constitution (specifically, the Sixth Amendment) calls for a jury to be "impartial," not a panel of experts. The judge instructs the jurors what is the legal definition of "insanity" and it's the jurors' job to determine whether the defendent meets that specific definition, not the clinical definition of insanity.

[dracoi]

In my mind, the whole point of the impartial jury of one's peers is to avoid bias that might be built into the jury selection.

For example, let's say that virtually all doctors are white. If a minority is accused of a crime, and can only be tried with a jury of doctors, then there's virtually no chance that other members of the accused's minority will be on the jury.

There's also the fact that medical professionals are not necessarily right. Doctors have believed (and done) some pretty stupid things, even in recent history. This is especially true of mental illness. As experts, they may be better educated, but it will be pretty hard to convince them that they're wrong, even when they are.

So... while a jury of non-professionals has some disadvantages, it also has some advantages.

[Senegoid]

Having a case that depends heavily on very technical information (and sometimes lots of it) presents serious problems. Consider the cases of high-level financial skulduggery, as alleged against banks and financial companies, or the Enron case. It's nigh impossible to prosecute such cases due to the mountains of detailed technical data that even the prosecutors can't plow through, let alone be comprehensible to a lay jury.

I had a statistics teacher once to mentioned that he is often called as an expert witness to teach statistics to the jury so they can "understand" what-the-hell everybody's talking about. His point was that it's a monumental task just to try that, with no assurance at all that the jury will ever have a clue.

It's a serious problem with our justice system, and needs more thought on how to deal with it. I'm vaguely inclined to prefer technically knowledgeable juries, with due process for choosing them in some unbiased way.

ETA: That also has to include some way, as best someone can figure, to avoid the kind of problems that dracoi mentions just above.

[MikeS]

Another point is that the jurors are only supposed to make their decision based on the evidence being presented in the courtroom, rather than their own personal knowledge. The defense is supposed to have a chance to address the assertions that are being used to implicate the accused. If a doctor pulls in some specialized factoid from their own experience, and decides that the accused is guilty on that basis, then the defense didn't have a chance to address that issue which could lead to a miscarriage of justice.

[pravnik]

Having doctors on the jury won't necessarily help unless they were trained in forensic psychology or forensic psychiatry - an OBGYN may be brilliant in their field but if they aren't schooled in the law of insanity of the jurisdiction and how it intersects the mental state of the defendant they might as well be a plumber. An expert is a translator, in a sense; I'm a strong, strong believer that an expert brought into court to help inform a jury to understand a technical issue should above all else be able to make that testimony understandable to a jury, otherwise what's the point? If an attorney just brings in an expert to spout off some impressive jargon that the jury doesn't understand, there's no point in having expert testimony at all.

[Dereknocue67]

Wouldn't having an all doctor jury cause anxiety attacks with the attorneys? This may reduce their strategy to having to deal with and argue the facts.

[Keeve]

I agree with Senegoid's main point, which I understand to be the idea that the OP's question applies not only for medical doctors, but for any case heavily dependent on expert testimony. I've often felt that many such cases are decided not by we are right or they are right, but by whether our experts are more or less convincing than their experts. This problem would certainly be solved by having experts on the jury.

As far as how a jury is supposed to work, MikeS's understanding is very different than mine. I've served on a jury several times, and my understanding is that the jury is expected to draw on their general and specialized knowledge and experience. The main thing that juries are to avoid is specific knowledge of this case.

[Jackmannii]

The value in having a physician (or other highly trained individual) on the jury would be not for a specialized subset of knowledge, but for the ability to think critically, something most people (and unfortunately, quite a few doctors) don't have.

In my very limited jury pool experience, lawyers (especially defense attorneys in criminal cases) do not want physicians on the jury. They want their own experts to carry the day, with opinions filtered through the presenting attorney(s), without some smart-ass physician giving it his/her own interpretation. Besides, physicians are often presumed to be politically right of center and unsympathetic to criminal defendants.

If a forensic psychiatrist actually wound up in the jury pool for a case with an insanity defense, he/she'd be blackballed in record time.

[MikeS]

Originally Posted by Keeve

As far as how a jury is supposed to work, MikeS's understanding is very different than mine. I've served on a jury several times, and my understanding is that the jury is expected to draw on their general and specialized knowledge and experience. The main thing that juries are to avoid is specific knowledge of this case.

I'll freely admit that I may have misunderstood what I've read about the role of outside knowledge and expertise in jury deliberations.

[Alley Dweller]

Juries aren't asked to make a medical diagnosis, they are asked to make a legal diagnosis (so to speak). Even though the law might use the same term as a doctor might employ (or a popular newspaper might use a medical term to describe a legal concept), a lawyer and a psychologist might understand the term differently. The jury is asked only to decide if the defendant fits the definition of insanity as spelled out in the controlling body of law, not whether the defendant needs a course of medical treatment.

A typical doctor is no more an expert on the law than any other typical juror.

And anyway, a behaviorist (Ph. D.) might strenuously object to entrusting such a decision to a panel of psychiatrists (M. D.s). A disciple of Skinner would consider a disciple of Freud to be a quack and vice versa.

[Dendarii Dame]

Another factor to consider is that doctors may be more likely to receive an excuse from serving on a jury (especially for long trials), given that they have what's considered a vital profession in the community.

As far as defense counsel not wanting experts on the jury, my father has never served as a juror. He's a retired financial analyst, and although he was interviewed for quite a few civil trials, as soon as he says what he used to do for a living, the defense counsel rejected him. His theory is that they think he knows too much about the value of money to give a large award.

[md2000]

The thing is that specialist often tend to be very full of themseles. Psychiatry, for example, took a 100-year wrong turn because Freud was too chickenshit to suggest what was obvious, that his typical patients, women suffering from "hysteria", were actually the victims of childhood sexual molestation. Instead, he made up (deliberately, according to some) the whole Oedipus/Electra/sexual obsession crap and 100 years of pyschiatrists adored him and swallowed it hook line and sinker.

the short answer is, we have no idea what insanity usually is or exactly what causes it. The goal of a jury of randomly selected persons from all over society is to decide whether actions in a particular case fall in the category of "criminal insanity" whatever the local definition. (Usually "unable to distinguish right from wrong".)

(Aside - IMHO anyone who shows suficient ability to pre-plan their actions, including steps to avoid detection, and possibly hide their actions afterwards - displays knowledge that society disapproves of these actions, and so cannot complain they had no idea they were doing "wrong". If Hinckley, for example, had the wherewithal to transport a weapon around the USA without having it confiscated at the airport gate, and keep that gun hidden from the Secret Service until he used it, does he really not understand what he is doing is not approved by society? IMHO... )

Besides, a "jury" of experts is a limited pool. Just as both sides can produce their "experts" and get testimony exactly the way they want - a small jury pool is easily subject to becoming commonly known and the "right" people get selected. "Pick Dr. A; he's known to be soft on abused mothers..." Add jury shopping to judge-shopping. Even for experts, what is or is not legal insanity is a personal opinion and a crapshoot.

And... a jury of experts does not come cheap. If a good psychiatrist can make, let's pretend, $120,000 a year (sounds low) they are not going to accept $12/day. Do you really want to add $10,000 times 12 for a one-month trial - for no real benefit.

[pravnik]

Originally Posted by md2000

And... a jury of experts does not come cheap. If a good psychiatrist can make, let's pretend, $120,000 a year (sounds low) they are not going to accept $12/day. Do you really want to add $10,000 times 12 for a one-month trial - for no real benefit.

I was about to bring up that exact point. Not only that, you'll end up paying them a lot more because you're paying them their gross and not their take home pay, since they're using that money to keep their lights on and secretaires paid as well as paying themselves. Forensic psychologists and psychiatrists generally charge about $250 to $350 an hour, so the state is paying about $3000 an hour to expert jurors, not including the experts that are testifying. That comes out to about $120,000 for a week long trial, not including deliberation or travel time. Getting paid that kind of scratch, I would anticipate doctor juires having lengthy, lengthy deliberations.

[doorhinge]

Originally Posted by kunilou

The Constitution (specifically, the Sixth Amendment) calls for a jury to be "impartial," not a panel of experts. The judge instructs the jurors what is the legal definition of "insanity" and it's the jurors' job to determine whether the defendent meets that specific definition, not the clinical definition of insanity.

That's my impression also. The jury is only there to hear the evidence and decide, based on that evidence and only that evidence, if the defendent is guilty or innocent.

It's up to the State to provide evidence in a manner that the average juror can understand.

[AHunter3]

Originally Posted by Confused dart cum

Would it not make a considerable deal more sense for doctors to be the jury for cases like this 'un:



Surely said jury should be made up of doctors if its decision is to be accorded any respect?

(No comment on the merits of this verdict is intended by this post)

Good god, no. Bite your tongue. Doctors have way too much power as it is in cases pertaining to alleged state of mind and so forth. All psychiatric retention events should be decided in cases where medical diagnosis is prohibited from being mentioned at all. Shrinks should have to testify to actual facts to convince a jury, without reliance upon expert medical matters, that the person is not competent.

[pravnik]

Originally Posted by AHunter3

Good god, no. Bite your tongue. Doctors have way too much power as it is in cases pertaining to alleged state of mind and so forth. All psychiatric retention events should be decided in cases where medical diagnosis is prohibited from being mentioned at all. Shrinks should have to testify to actual facts to convince a jury, without reliance upon expert medical matters, that the person is not competent.

You really think so? Like, if a criminal defendant committed a crime while out of touch with reality due to psychosis, testifying forensic psychiatrists should be prohibited from saying that the defendant suffers from a psychotic disorder? (Not attacking your position, mind you, just genuinely curious)

[AHunter3]

Originally Posted by pravnik

You really think so? Like, if a criminal defendant committed a crime while out of touch with reality due to psychosis, testifying forensic psychiatrists should be prohibited from saying that the defendant suffers from a psychotic disorder? (Not attacking your position, mind you, just genuinely curious)

If the defendant, in the shrink's opinion, is out of touch with reality in the legally meaningful sense, let the shrink demonstrate it with the defendant on the stand.

We are responsible for our actions. The exceptions are limited to "this person is not competent" (which is something you should be able to DEMONSTRATE not just testify to) and "this person lacks the ability to discern right from wrong" (which again is generally something you need to convince the jury of, not just testify to as a 'medical' matter).

I don't think it should be legal to mention that someone has been diagnosed "schizophrenic" or "bipolar" or whatever in a court of law. Or mention of such things should be considered suspect and narrowly limited.

[md2000]

Also, "experts" are more full of themselves and less likely to compromise on what they see as "right" according to their opinion in their specialist professional field. So you will see a lot more hung juries, if you stick to the demand that all 12 agree on a verdict.

I believe the whole idea of a jury is to avoid specialists in ivory towers, and ask the average collection of Joe Schmoes if their decision makes sense in the real world.

[pravnik]

Originally Posted by AHunter3

If the defendant, in the shrink's opinion, is out of touch with reality in the legally meaningful sense, let the shrink demonstrate it with the defendant on the stand.

We are responsible for our actions. The exceptions are limited to "this person is not competent" (which is something you should be able to DEMONSTRATE not just testify to) and "this person lacks the ability to discern right from wrong" (which again is generally something you need to convince the jury of, not just testify to as a 'medical' matter).

I don't think it should be legal to mention that someone has been diagnosed "schizophrenic" or "bipolar" or whatever in a court of law. Or mention of such things should be considered suspect and narrowly limited.

To a degree, I would agree with that - if an expert simply comes in, shows his degree to the jury and says "this person was legally insane at the time of his crime because he is schizophrenic" and leaves, then he hasn't really given the jury anything to help them make their decision. The diagnosis needs to be tied to the reasoning and data behind why he meets the legal definition of insanity, what the defendnant's particular state of mind was at the time, etc. Additionally, diagnostic information is important to tell the jury why the expert believes that the defendant isn't malingering his symptoms, or just as importantly, for a state's expert to tell the jury why the defendant is malingering his symptoms, or why he doesn't meet the legal definition of insanity or incompetency even though he is schizophrenic or what what have you. I'd agree that an expert has to demonstrate and justify his opinion through facts and data and do much more than simply a diagnosis, but I can't see any good reason not to allow diagnoses whatsoever; it seems like it would just hamstring state, defendant and court's experts alike in giving their testimony.

[pravnik]

Originally Posted by AHunter3

If the defendant, in the shrink's opinion, is out of touch with reality in the legally meaningful sense, let the shrink demonstrate it with the defendant on the stand.

Forgot to ask: do you mean the defendant should be required to testify, and the expert then tells the jury what it just saw?

[AHunter3]

Perhaps if the judge were always to instruct the jury, something akin to "You have heard testimony to the effect that the defendant Joe Schmoe is schizophrenic. In considering all relevant testimony in this case, you are to keep in mind that a schizophrenic is a competent person of sound mind until and unless demonstrated otherwise; that having a diagnosis of schizophrenia in no way indicates a lessening of legal responsibility for one's actions. You may also hear or have heard testimony from Joe Schmoe, and you are to regard that testimony as convincing or less than convincing on its own merits; having a diagnosis of schizophrenic does not impugn the reliability of any testimony presented by Joe Schmoe as a witness."

But I'm not sure that in the current cultural climate it wouldn't be the case that for many potential jurors it would still be ... what's the legal term for it, 'prejudicial'? When you bring up some 'ad hominem' factor that is so widely regarded as discrediting that jurors would find it difficult to set aside even if instructed to do so?

[AHunter3]

Originally Posted by pravnik

Forgot to ask: do you mean the defendant should be required to testify, and the expert then tells the jury what it just saw?

The expert could conduct an interview with the defendant in front of the jury. The opposing counsel could have their own expert conduct a similar interview. The jury would have the opportunity to consider how they themselves would answer any such questions and whether they consider the answers to illustrate that the defendant isn't all there in the head.

The attorneys could subsequently interview their expert witnesses for their interpretations and try to put their own spin on it, I guess. But the burden of proof should be on whatever party is alleging that the defendant lacks capacity; for failure to demonstrate that such is the case, the default assumption should be one of competency, and the jury should be instructed to that effect.

[MikeS]

Originally Posted by AHunter3

The expert could conduct an interview with the defendant in front of the jury. The opposing counsel could have their own expert conduct a similar interview. The jury would have the opportunity to consider how they themselves would answer any such questions and whether they consider the answers to illustrate that the defendant isn't all there in the head.

The attorneys could subsequently interview their expert witnesses for their interpretations and try to put their own spin on it, I guess. But the burden of proof should be on whatever party is alleging that the defendant lacks capacity; for failure to demonstrate that such is the case, the default assumption should be one of competency, and the jury should be instructed to that effect.

Wouldn't this effectively require a defendant to waive their Fifth Amendment rights (I'm assuming we're talking about the U.S. here) in order to mount an insanity defense? Not that this is necessarily a deal-breaker — for all I know, there are other types of legal defense that require the defendant to testify.

[AHunter3]

Originally Posted by MikeS

Wouldn't this effectively require a defendant to waive their Fifth Amendment rights (I'm assuming we're talking about the U.S. here) in order to mount an insanity defense? Not that this is necessarily a deal-breaker — for all I know, there are other types of legal defense that require the defendant to testify.

The defense attorney could choose not to have the defendant on the stand, and that would include not having questions posed by the expert shrink, but the cost of that would be that the defense could not claim that "insanity" (lack of capacity to tell good from evil) had been demonstrated. The defense attorney would be limited to what could be argued from evidence otherwise presented.

[pravnik]

Originally Posted by AHunter3

The defense attorney could choose not to have the defendant on the stand, and that would include not having questions posed by the expert shrink, but the cost of that would be that the defense could not claim that "insanity" (lack of capacity to tell good from evil) had been demonstrated. The defense attorney would be limited to what could be argued from evidence otherwise presented.

One big problem, though, even aside from any possible privileges against self incrimination: insanity goes to the defendant's mental state at the time of the offense, not at the time of the trial. For example, if Jared Loughner is ever restored to competency through medication and therapy, any evaluation of his behavior on the stand is going to have tangiental relevance at most as to what his mental state was at the time of the offense and whether he was sane or insane at the time.

Moreover, even if his mental state at trial was relevant to his sanity, doing a full mental exam in front of the jury would be incredibly trying on their patience and attention - mental status exams involve a lot of boring stuff like asking the interviewee to count backwards from 100 by threes and then sevens, remembering three common words several minutes apart, interpreting the meaning of common sayings, and so on, some of which will wind up being relevant and some of which won't, and all of which will take several hours. It's far better to let the expert conduct his interview at his leisure one on one and report a summary of their findings to the judge or jury rather than do the entire thing with the defendant on the stand in a courtroom in front of a few dozen people. Moreover still, experts don't solely rely on the interviews they conduct; in some circumstances the defendant may be too agitated and noncompliant to even speak to an expert. Experts also rely on a thorough record review, including any witness statements and statements of the defendant, police reports, medical records and records of previous psychological problems and psychiatric history, etc.

[AHunter3]

The interview could be taped, edited to show the relevant parts, and then shown in the courtroom, I suppose. (Opposing counsel would need to be provided with the full length tape, though, so they could contest "cherry picking" of footage and select other segments to show the court in rebuttal).

I'm aware of the self-incrimination consideration. If it is the defendant's OWN attorney who wishes to assert that the defendant is non compos mentis then presumably that issue is irrelevant.

[clairobscur]

Rather than picking psychiatrists as juror, why not skip entirely the jury part?

That's what's done over here. Determining whether or not the accused was legally insane is done early on, and there's no trial at all in this case (though someone can still go to trial, and be acquited by the jury for reason of insanity, it's expected to be the exception rather than the norm)

[ToeJam]

Originally Posted by md2000

the short answer is, we have no idea what insanity usually is or exactly what causes it.

Just a word of caution, this is a rather broad statement, and actually there are many types of psychiatric illnesses that have a biological basis or medical basis and are better understood. Otherwise your statement would rule out most jobs for Forensic psychiatry, who has to be trained not only in the medical definitions of psychiatric illness and diagnoses but also on legal definition as well, as the two do not always coincide.

[Nametag]

It's been touched on briefly, but it should be remembered that legal "insanity" is not mental illness, and most mental illness does not constitute legal insanity. Almost all crimes require an element of intent, and the legal definitions of insanity respond to the idea that some people are incapable of forming that intent. A doctor's understanding of insanity does not map well onto the legal usage, and for that reason I don't see value in the OP's proposal.

[Elendil's Heir]

G.K. Chesterton on the great social value of a non-expert jury: http://www.readbookonline.net/readOnLine/20725/

As to expert witnesses in insanity cases, a New Mexico legislator just might have had the right idea: http://blog.lawinfo.com/2012/02/10/w...en-testifying/

[doorhinge]

The basic premise of criminal law is that laws are supposed to be written so that "the people", the common man on the street-type person can undersatnd it. No law degree or medical degree is required to obey the law.

Those same people will be ones who make up a Grand Jury and or Petite Jury.

Appellate court cases are heard by judges who have an understanding of the law because they are deciding the "legal merits" of the case. Should some or all the evidence have been entered or excluded? Is the law actually "Constitutional"? Did the defendant recieve a "fair and impartial" trial? Were some jurors excluded unfairly?

[AHunter3]

Originally Posted by ToeJam

Just a word of caution, this is a rather broad statement, and actually there are many types of psychiatric illnesses that have a biological basis or medical basis and are better understood

Not really, no, not if you're referring to schizophrenia, bipolar disorder, clinical depression, the various anxiety disorders, attention deficit disorders, or obsessive disorders. Despite widespread and long-lasting claims to the contrary, there is a dearth of empirical support for claims of "chemical imbalances in the brain" of various posited sorts. See Anatomy of an Epidemic.

[doorhinge]

A jury is expected to decide if a defendent knows the difference between "right and wrong" based on the evidence presented in court. Guilty but insane, not guilty by reason of insanity, or whatever the proper legal response is based on that State's law.

If someone were to murder a person and then tried to clean up the evidence and hide the body, it's obvious that they knew they had done something "wrong". The legal definition/requirement of insanity would not have been met.

[ToeJam]

Originally Posted by AHunter3

Not really, no, not if you're referring to schizophrenia, bipolar disorder, clinical depression, the various anxiety disorders, attention deficit disorders, or obsessive disorders. Despite widespread and long-lasting claims to the contrary, there is a dearth of empirical support for claims of "chemical imbalances in the brain" of various posited sorts. See Anatomy of an Epidemic.

Well, that's better to be more specific. I was referring to Dementia, Delirium, and various intoxications and substance use for psychiatric illnesses which tend to get called out for Legal "Insanity" vs. Medical "insanity". Those are the some of the more common tricky cases where a brief period of psychosis may have occurred or some aberrant behavior, causing said person to run afoul of the law.

I certainly agree that there are plenty of mental illnesses that aren't explained fully biologically yet, however, I was cautioning of using the brush to paint them all as such.

[JoseB]

Question from someone who (most definitely) is not a lawyer, nor a psychiatrist. As far as I can understand, the legal definition of insanity is "cannot distinguish right from wrong", and that things like trying to hide the murder weapon, or carefully planning ahead, point towards an ability to do so.

Let us consider this hypothetical: someone is deeply paranoid (of the "they are all going to get me" variety) (NB: as I said I am not a psychiatrist; maybe my understanding of paranoia is wrong). He is afraid that he will be killed by someone who is after him, and doesn't dare to go to the police because he is convinced that they are in on the plot.

Anyway -- this person finally goes and kills the person who, in his delirium, he sees as his main "persecutor". But this persecutor is not the only one! There is a shadowy cabal of enemies who, if they were to find out that he (I refer to the paranoid individual here) had killed one of their number, they would undoubtedly take their revenge in force against him!

So, in order to protect himself from this imaginary organization, he does his best to hide the murder, and takes all conceivable steps to plan the murder so that he is not connected to it.

This is, obviously, a contrived situation. Nonetheless, in this hypothetical case, would it be possible to mount a successful insanity defense? Or would the fact that there was planning, premeditation and concealment automatically make that person legally responsible, even though they may have been genuinely in fear of his life? (if only through delirious ideation).

I have no answer, but would like to hear your opinion.

[doorhinge]

Originally Posted by JoseB

.....Let us consider this hypothetical: someone is deeply paranoid (of the "they are all going to get me" variety) (NB: as I said I am not a psychiatrist; maybe my understanding of paranoia is wrong). He is afraid that he will be killed by someone who is after him, and doesn't dare to go to the police because he is convinced that they are in on the plot.

Anyway -- this person finally goes and kills the person who, in his delirium, he sees as his main "persecutor". But this persecutor is not the only one! There is a shadowy cabal of enemies who, if they were to find out that he (I refer to the paranoid individual here) had killed one of their number, they would undoubtedly take their revenge in force against him!

So, in order to protect himself from this imaginary organization, he does his best to hide the murder, and takes all conceivable steps to plan the murder so that he is not connected to it.

This is, obviously, a contrived situation. Nonetheless, in this hypothetical case, would it be possible to mount a successful insanity defense? Or would the fact that there was planning, premeditation and concealment automatically make that person legally responsible, even though they may have been genuinely in fear of his life? (if only through delirious ideation).

A defendant can not claim that they're "CrAzY about that sort of thing" and shouldn't be tried for violating the law. An insanity defense requires testing by experts. If the defendant's state of mind, or the defendant's state of mind at the time of the crime, can convince an expert that they were not "responsible" for their criminal conduct, the expert will either try to convey their reasoning to a jury or the State will confine the defendant to a hospital until they are able to stand trial.

Historically-speaking, first there was the "M'Naughten rule" which was replace by the "Durham Rule" which was replaced by the "Model Penal Code".

"A person is not responsible for criminal conduct if at the time of such conduct as a result of mental disease or defect he lacks substantial capacity to appreciate the wrongfulness of his conduct or to conform his conduct to the requirements of the law" (Model Penal Code § 4.01[1]).

To answer your question, a truly paranoid person who believed that "everyone was out to get them" and believed they had to use lethal force to rid the world of their enemies (which includes everyone) is nuttier than a porta-potty at a peanut farm and should not be allowed to roam free in society. The State can order the defendant to submit to treatment in a State recognized mental heathcare facility until it's believed that they are "sane" enought to stand trial. (Your State's rules may vary.)

[md2000]

Originally Posted by ToeJam

Well, that's better to be more specific. I was referring to Dementia, Delirium, and various intoxications and substance use for psychiatric illnesses which tend to get called out for Legal "Insanity" vs. Medical "insanity". Those are the some of the more common tricky cases where a brief period of psychosis may have occurred or some aberrant behavior, causing said person to run afoul of the law.

I certainly agree that there are plenty of mental illnesses that aren't explained fully biologically yet, however, I was cautioning of using the brush to paint them all as such.

I'm not saying we can't tell if someone is insane (usually) legally or medically. What I mean is there is no test (here, pee into this cup, deeeep breath, please stand in this Xray machine) where we can point to and say "A" has schizophrenia, "B" does not- or almost every other medical mental health problem. We're not even close to that level of understanding. We don't even have real drugs to treat the problem, we just put people into a lethargic haze which minimizes the risk of "attacks". We instead have to rely on people who are fallible, but have dealt with many such cases, who check off a long list of symptoms and say "it's very likely A has this problem."

Educated people in a field have agendas just like you and I. Some are smart and honest and impartial, and some can testify to what is needed for cash, and some are partial to a certain interpretation of the facts.

Determining if a person is legally insane is best done by explaining things to 12 people off the street and see if it passes the sniff test to them, as well as to the experts paid to testify.