Settled insanity

Settled insanity is defined as a permanent or "settled" condition caused by long-term substance abuse and differs from the temporary state of intoxication. In some United States jurisdictions "settled insanity" can be used as a basis for an insanity defense, even though voluntary intoxication cannot, if the "settled insanity" negates one of the required elements of the crime such as malice aforethought. However, U.S. federal and state courts have differed in their interpretations of when the use of "settled insanity" is acceptable as an insanity defense and also over what is included in the concept of "settled insanity". Early English common law recognized "settled insanity" as a complete defense for a person who is a habitual drunk but is not intoxicated at the time of the offense. A complete defense exonerates the accused and is a verdict of not guilty. Thus a person meeting the criteria of "settled insanity" is not considered responsible for his actions. Under the M'Naghten Rules, the first attempt in criminal law to address the issue of a mentally ill defendant, mental illness (or insanity) can be used as a defense if the defendant was unable to understand the criminal nature of his act or was unable to distinguish right from wrong at that time of the offense. The standard for an insanity defense developed by the American Law Institute requires a showing that the defendant's mental illness prevented him from abiding by the law. Traditionally, under English common law intoxication, no matter to what degree, was not considered grounds for excusing the defendant's criminal behavior. However, over the last half century, there has been a movement toward allowing intoxication as evidence admissible in court to help the jury understand the criminal act and perhaps use it as an excuse or a mitigating factor. Although voluntary intoxication is not considered an excuse for a criminal act, if it can be shown that the defendant was too intoxicated to deliberate or premeditate the wrongful act, (lacking malice aforethought), a defense of diminished capacity, while not excusing the defendant from responsibility for the act, can serve to reduce the charges.