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Are Personality Disorders Mental Illnesses? The Legal Implications.

Mental illness as a concept is nebulous and far reaching. Depending on context, philosophy and other factors, what constitutes a mental illness is subject to debate. Most would agree, at least, that serious mental illness encompasses disorders like Schizophrenia, Bipolar Disorder and Major Depressive Disorder, although some may argue that others also belong in this category. However, with diagnoses like Generalized Anxiety Disorder, Paraphilias or Posttraumatic Stress Disorder, it is less clear if these constitute major mental illnesses in the same way as the former group (although each can certainly cause major life disruptions).

Personality Disorders vs. Serious Mental Illness

The water gets even murkier with personality disorders – a subject that is immensely complex in its own right and can’t be comprehensively addressed here. Most would agree, at least to some extent, that personality disorders are of a different type and do not constitute mental illness in the commonly understood sense. Put another way, if you ask the average person what mental illness is, they are unlikely to describe the features of a personality disorder.

Mental illness, in the traditional sense, tends to manifest as a major set of obvious and life-disrupting symptoms. Schizophrenia, for example, is characterized by hallucinations, odd beliefs, significant emotional impairment, disorganized behavior and thinking and serious dysfunction across many areas of life. Bipolar Disorder manifests as distinct, severe and longstanding mood states, ranging from erratic and risky behaviors to debilitating depressions that last for months. In these and other major mental illnesses, the symptoms significantly interfere with the person’s functioning , their ability to care for themselves, and is often accompanied by subjective distress. Even less severe mental illnesses have similar manifestations and impacts. For example, the anxiety sufferer may avoid certain events or being in large crowds and the paraphilic may have distressing fantasies or images that they sometimes act upon.

Overall, the key features of these typical mental illnesses are objective symptoms, life dysfunction and subjective distress, each of which can play motivational roles for the patient to desire change and even seek help. Of course, not all sufferers recognize they are ill, nor are all motivated to seek help.

Personality disorders are markedly different. While they certainly have cognitive, emotional and behavioral symptoms as defined by the Diagnostic and Statistical Manual of Mental Disorders – 5th Edition (DSM 5), conceptualizing them only by these symptoms does not capture their true nature and minimizes the actual severity and reality.

The core of the personality disorder is that the manner in which the person relates to all others in the world is fundamentally broken. Each interaction with the world is distorted by the dysfunctional filter that defines their disorder. While one would rightly expect mental illnesses like Schizophrenia or Bipolar Disorder to interfere with the sufferers’ ability to interact appropriately in the world, relationship dysfunction is the key manifestation in the personality disorder.

Although the DSM 5 indicates that significant distress is a defining feature of the personality disorder, this allegation is often undone in the individual descriptions of the disorders. In fact, most personality disorders are marked by the lack of subjective distress and/or awareness that one is “ill.” If a personality disordered person were to admit distress, it would more likely be due to a peripheral problem (e.g. depression after a divorce) or if they sought help, it would be because others pressured them to do so. It would be highly unusual for a truly personality disordered person to seek help due to suspecting they themselves are the problem.

Personality disorders need to be understood as fundamentally different from other mental illnesses. We need to think about the person themselves as being the disorder. While major mental illness are diseases that people have, personality disorders are that diseases that people are. It is the very essence of the person that is disordered, which, in turn, affects every aspect of their life and the lives of those around them.

Implications for the Legal System

What does this mean for legal issues in which mental illnesses, diseases or defects are involved? When a legal statutes invokes “mental disease or defect,” do personality disorders qualify? Are they mental illnesses in the sense that the public, attorneys and courts understand? Legal professionals and juries alike may not give much thought to the distinction between traditional mental illnesses and personality disorders. From the outside looking in, a diagnosis may just be a diagnosis, but the issue could quickly become more complex and have significant impacts on a legal case.

For example, when the insanity defense is invoked, it seems to imply a major defect in reasoning, appreciation and volition; the law sets a high bar in order to render someone not criminally responsible. The language in Illinois’ insanity statute supports this contention: “For purposes of this Section, “mental illness” or “mentally ill” means a substantial disorder of thought, mood, or behavior which afflicted a person…” [§ 720 ILCS 5/6-2(d), 2012; emphasis added]. Personality disorders do not seem to fulfill the spirit of this definition, as significant thought, mood and behavioral disruptions are not the common features.

Additionally, some legal statutes’ definitions forbid the inclusion of mental disorders that render one a chronic criminal offender. For example, in Missouri: “The terms “mental disease or defect”…do not include an abnormality manifested only by repeated criminal or otherwise antisocial conduct, whether or not such abnormality may be included under mental illness, mental disease or defect in some classifications of mental abnormality or disorder…[and] do not include…an abnormality manifested only by criminal sexual psychopathy.” [§ 552.010, 1969]. Illinois uses very similar language in their definition, as do many other states.

Such definitions clearly exclude diagnoses like Antisocial Personality Disorder, which has lawbreaking as a defining feature, but this begs a greater question about the law’s overall intent. While legislatures may not have had what mental health professionals categorize as ‘personality disorders’ in mind when they constructed their statutes, they appear to have had an understanding that all disorders do not have the same impact on one’s thinking, feeling and behavior and, by extension, their ability to appreciate the nature, quality and wrongfulness of their actions. Both law makers and mental health professionals seem to consider at least some personality disorders unique from other mental illnesses, but both groups also struggle with exactly where they fit and how the law should account for them.

When a person with a personality disorder commits a criminal act, a reasonable attorney or forensic mental health professional would need to pause and carefully consider if such a disorder should be factored into a legal defense or the court’s consideration of the crime. As a simple example, if a defendant with Narcissistic Personality Disorder killed their neighbor after feeling insulted by them, could the disorder qualify as a mental disease or defect under the law? NPD is not characterized by a “…substantial disorder of thought, mood, or behavior…” as noted in the Illinois definition. In fact, narcissists, as difficult and obnoxious as they can be, are not often irrational, illogical, prone to violence or severely disordered in the way mental illnesses are traditionally thought to be. However, their grandiosity and entitlement has great potential to wreak havoc on the lives around them and a perceived slight against their greatness could conceivably result in a violent crime. However, it also does not have “…repeated criminal or otherwise antisocial conduct…” as a core feature, as noted in Missouri’s definition; thus, it is not automatically ruled out.

If this defendant invoked the insanity defense, is it arguable that their pathological belief that they are superior to others rendered them unable to appreciate the nature, quality and/or wrongfulness of their murderous act? As it relates to the insanity defense, the same questions that would be examined with any other defendant would need to be considered, but perhaps the most challenging question would be do they qualify under the definition of mental disease or defect? Given the unique place mental illness holds within the law and the fundamental qualities of the personality disorder, it seems unlikely.

The intersection of mental illness and law is already complex for many reasons, including that mental health professionals and legal statutes define mental illness quite differently. Nevertheless, courts ask forensic experts to help them bridge the gap between what the statutes say and what the experts know about the true manifestations of mental illness. It is incumbent upon the expert to understand the nuances of mental illness diagnoses, including and especially the unique subset of personality disorders. Of course, they are not immune from criminal involvement, but more importantly, the court relies on our expertise to flesh out and explain the differences between them and more common understandings of mental illness.

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