Insanity is an informal term denoting mental instability. Today, medical professionals tend to avoid the term “insanity” in favor of “psychopathology.”  Mental disorders that were previously encompassed by the term “insanity” include schizophrenia, bipolar disorder, other types of psychosis and some neurocognitive disorders, such as dementia.

The term “insanity” is still commonly used within legal settings, however. The insanity defense, also called the mental disorder defense, is an attempt to reduce the severity of a charge or sentencing due to the fact that the defendant is not responsible for his actions because of severe mental illness.

Most courts accept major mental disorders, such as psychosis, for an insanity defense, but do not accept depression, anxiety or a less severe personality disorder. One major deciding factor in the insanity defense is whether or not the illness itself interfered with the defendant’s ability to know right from wrong. The insanity defense is used in less than 1 percent of felony cases, and only a fraction of these are actually successful. Those who are found not guilty of a crime due to insanity, are almost always committed to a psychiatric hospital indefinitely.

Example: The judge declared the defendant not guilty because of temporary insanity.