Personality Disorders as an Insanity Defense

Are personality disorders true mental illnesses and  should a person with a personality disorder be entitled to  use the insanity defense after committing a crime?

"It is an ill thing to knock against a deaf-mute, an imbecile, or a minor. He that wounds them is culpable, but if they wound him they are not culpable." (Mishna, Babylonian Talmud)

Some personality disorders are culture-bound. Critics charge that these "mental illnesses" mostly serve as an organizing social principle and are tools for societal control and coercion. But if personality disorders are not objective clinical entities - what should we make of the insanity defense (NGRI- Not Guilty by Reason of Insanity)?

The insanity defense (when a person is held not responsible for his criminal actions) rests on two pillars of evidence:

1. That the accused was unable to tell right from wrong ("lacked substantial capacity either to appreciate the criminality (wrongfulness) of his conduct" - diminished capacity).

2. That the accused did not intend to act the way he did (absent "mens rea") and/or could not control his behavior ("irresistible impulse"). These handicaps are often associated with "mental disease or defect" or "mental retardation".

Still, the "guilty but mentally ill" verdict appears to be a contradiction in terms. All "mentally-ill" people operate within a (usually coherent) worldview, with consistent internal logic, and rules of right and wrong (ethics). The problem is that these private constructs rarely conform to the way most people perceive the world. The mentally-ill, therefore, cannot be guilty because s/he has a tenuous grasp on reality. Mental health professionals prefer to talk about an impairment of a "person's perception or understanding of reality".

Reality, however, is a lot more shaded and complex that the rules that purport to apply to it. Some criminals are undoubtedly mentally ill but still maintain a perfect grasp on reality ("reality test"). They are, thus, held criminally responsible (Jeffrey Dahmer comes to mind). The "perception and understanding of reality", in other words, can and does co-exist even with the severest forms of mental illness. It is, therefore, not very helpful in distinguishing the criminally insane from the merely insane.

This makes it even more difficult to comprehend what is meant by "mental disease". If some mentally ill patients maintain a grasp on reality, know right from wrong, and can anticipate the outcomes of their actions, are not subject to irresistible impulses (the tests set forth by the American Psychiatric Association) - in what way do they differ from us, "normal" folks? Are personality disorders mental illnesses? Can someone with the Narcissistic Personality Disorder (a narcissist) successfully claim the insanity defense? Are narcissists insane?

This is the topic of our next article.

Click on these links to learn more:

The Myth of Mental Illness

The Insanity Defense

Crime and the Never repenting Narcissist

Serial Killers

This article appears in my book, "Malignant Self Love - Narcissism Revisited"


next: Is the Narcissist Legally Insane?

APA Reference
Vaknin, S. (2009, October 1). Personality Disorders as an Insanity Defense, HealthyPlace. Retrieved on 2024, June 15 from

Last Updated: July 5, 2018

Medically reviewed by Harry Croft, MD

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