Many people hear of cases where the defendant is deemed unfit to stand trial because of mental illness. In other cases, mentally ill defendants go to trial and plead insanity instead. What exactly is the difference? If both defendants are mentally ill, why are the cases treated so differently? This is what you should know. 

Mental illness and incompetency are different mental states.

The basic difference between the two types of cases comes from the fact that insanity and competency are actually two different things. Competency refers to the defendant's ability to understand the charges against him or her and the ability to assist with his or her own defense, which is considered part of your Constitutional 6th Amendment rights.

Insanity refers to the state of mind of the defendant at the time the crime was committed—not before or after. Someone may be temporarily insane, unable to appreciate the difference between right and wrong at the time of the crime, but otherwise sane. Similarly, someone with severe mental issues may still understand that their actions are wrong at the time they committed them.

Some can be legally incompetent and suffering from mental illness, but not insane.

Asking the court to declare a defendant mentally incompetent usually only delays the trial, not stops it. Many mentally-ill defendants simply need appropriate treatment and medication. Once they get it, their condition often improves, making it possible for them to be an active participant in their own trial and defense.

In other cases, however, incompetence won't get better through treatment. For example, the judge in the case of Jimmy "Superfly" Snuka has dismissed the murder charges against the former pro-wrestler because he suffers from dementia. While not legally insane, his dementia is severe and seems to be rapidly progressing. Since there's no cure for dementia, it's unlikely that the case will ever be brought back into court again.

Some defendants can be mentally ill but still competent to stand trial.

Mental illness doesn't always equate incompetence, even when it is severe. For example, a schizophrenic who hears voices may very well be capable of understanding any charges against him or her and can appreciate the seriousness of the offense. He or she may also still be quite capable of offering up a defense, even if it is an irrational one.

The problem with insanity defenses is that they are very difficult to achieve. Each state has its own definition of insanity and less than 1% of cases go to trial with an insanity plea. Only 25% of those cases succeed. Most people consider the insanity defense a "defense of last resort," for cases that truly baffle people.

For example, attorneys for one of the girls accused of trying to kill a classmate to appease the fictional character "Slender Man" entered a plea of not guilty by reason of mental disease or defect, which is the technical term for an insanity plea. Only 12 at the time she attempted the murder, she may have genuinely held the belief that the horror character was real and had to be appeased by such a sacrifice. Despite her beliefs, the girl has shown that she was competent to stand trial in several ways, including offering the explanation for her actions and trying to hide what she'd done from authorities.

If you or someone you love is a defendant in a criminal case and mental illness is involved, make certain that your defense attorney is aware of the problem. That may help the attorney craft a stronger defense down the line. Talk to a lawyer like Novak Lee Atty At Law for more information.