Out of all the things I lost, I miss my mind the most.

"The definition of insanity is repeating the same mistakes over and over again and expecting different results," utters the know-it-all guy in the coffee shop offering free "therapy" to his visibly shaken friend. He had all the tell-tale signs of the recently heartbroken, and Mr. Fix-It's platitudes didn't seem to be helping. I resisted the urge to butt in with a resounding "no it's not! That's the definition of perseveration!" but felt that my humbly nerdy correction wouldn't contribute much to the bromantic mood of gingerbread lattes and "who needs women" banter. So instead, I'll tell whoever wants to listen, right here, right now. This is not the definition of insanity. It never has been, and it probably never will be.

The above quote has been mis-attributed to Albert Einstein, Benjamin Franklin, and Mark Twain. In fact, none of these great minds were responsible for such a convincing, yet blatantly incorrect definition. The first time it actually appeared in print was in a 1981 Narcotics Anonymous text (page 11).

The term insane is outdated parlance in the mental health community. No legitimate medical or clinical professional would be caught dead saying it in public. It's a legal term. A defendant may be found not guilty by reason of insanity if his or her lawyer can provide clear and convincing evidence that he/she was suffering from severe mental illness (i.e., psychotic disorders like schizophrenia, bipolar disorders, or organic brain illness) which prevented him/her from knowing that the crime committed was, in fact, an illegal act. Because it is a legal distinction, and not a medical one, although forensic psychologists may offer clinical opinions about the mental health of a defendant, only a judge or jury can make determinations about a defendant's insanity.

The quote above is not the only myth about insanity that's commonly seen in popular psychology. Richard Nixon centered his crime fighting efforts against the insanity defense in 1973, attempting to abolish it entirely. A Wisconsin State Journal article quotes a Justice Department lawyer flippantly claiming that, "It does away with the defense of 'I was insane when I committed the crime, but, wonder-of-wonders, I've recovered.'"

Even presidents aren't immune to mythological thinking about popular science and psychology, especially when it adds ammunition to their political arsenals (surprise, surprise). Did Nixon really think that the insanity defense is a convenient loophole that allows for the most brilliantly nefarious thespians to malinger their ways out of prison and into, who knows, Hollywood? Do you think that the insanity defense is a common ploy in the courtroom? If so, do you think that a significant portion of these "criminally counterfeit" walk away scot free after sentencing?

If the idea of an insanity defense sits like a rock in your stomach, and you worry that it is commonly abused, you're not alone. In a 2007 study, undergraduate students were questioned about their attitudes toward the use of the insanity plea in the United States. Students estimated that the defense was used in approximately 30% of cases and was successful approximately 30% of the time. Sound reasonable?

In fact, the insanity defense is used in only 1% of all criminal proceedings, and its success rate is only 25% of that 1%. Therefore, less than 1 in 400 defendants are found not guilty by reason of insanity in this country. Some studies show this rate as being much lower -- closer to 1 in 1000. Public estimates of the number of insanity acquittals are as high as 81 times the actual number. Furthermore, there appears to be no significant difference in length of time served for murder between incarcerated sane criminals and insane persons who were involuntarily committed.