Mental Illness and Violence

Posted by Sappho on August 16th, 2013 filed in Bipolar Disorder

How far are people with mental illness more likely to be violent than “normies”? How far does mental illness mitigate responsibility? And how far are people with mental illness, rather, more likely to be victims of violence than perpetrators? In this post, I round up a few links that discuss these issues.

The first thing to note is that the DSM includes many diagnoses, and some of these diagnoses are indeed more associated with criminality, for a particular reason.

… the ones that are more closely linked to criminality include antisocial personality disorder, impulse control disorders (eg, intermittent explosive disorder, kleptomania, pyromania, and pathologic gambling), and paraphilias (eg, voyeurism, exhibitionism, frotteurism, and pedophilia).

However, individuals with these illnesses are not criminals merely because they have the disorder. It is more accurate to say that these disorders are more closely linked to criminality, because the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) criteria for diagnosing these disorders include symptoms that tend to violate the rights of others.[1]

It is essential to keep in mind that most people with mental illness are not violent.[2] A study of psychotic individuals found that those with a mental illness were responsible for only 5% of all violent crimes….

Some disorders that aren’t defined by symptoms that tend to violate the rights of others are, to one degree or another, associated with a greater risk of violence, but the picture is complicated.

Mentally ill people are far more likely to be victims of violence than the general population, to the point where they are more likely to be victims of violence than perpetrators.

An overview of the literature on violence and mental illness reports that

However, although the main risk factors for violence still remain being young, male, single, or of lower socio-economic status, several more recent studies have reported a modest association between mental illness and violence, even when these elements have been controlled

The same overview reports that, when surveyed, people consistently overestimate the risk of violence among the mentally ill, although they correctly identify substance abuse as one of the higher risk factors.

Alcohol abuse/dependence and antisocial personality disorder are the greatest risk factors.

Natasha Tracy (who specializes in writing about bipolar disorder) has a thoughtful piece at Healthline discussing the degree to which bipolar disorder is associated with violence. There is some elevated risk, particularly in mania and mixed states, that is greatly increased if there are comorbid disorders like substance abuse and personality disorders.

The numbers are actually staggering. According to the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), in people without a psychiatric condition aggressive behavior was found in 0.66 percent of persons over the course of their lifetime. In people with bipolar disorder I, the number climbs to a shocking 25.34 percent and in bipolar II the number is 13.58 percent.

(Aggressive behavior is defined as an “overt act intended to harm.”)

The numbers for bipolar disorder represent those with and those without comorbidities (co-occurring disorders). We’ve always known that those with alcohol or drug abuse issues have much higher numbers of violence and other comorbidities like personality disorders also increase the risk of violence, but this doesn’t account for the whole difference.

In those with bipolar disorder without comorbidities, the numbers on violence are:
2.52 percent in bipolar I
5.12 percent in bipolar II

Borderline personality disorder (though, like bipolar disorder, it is still more strongly associated with suicide attempts than with violence) appears to be more strongly associated with violence than bipolar disorder. Here’s a study reporting that

Findings showed that 73% of BPD subjects engaged in violence during the one-year study period, and frequently exhibited co-morbid antisocial personality disorder (ASPD) and psychopathic characteristics.

That percent looks awfully high to me, and single studies should always be treated with caution. Here’s a review of the literature on borderline personality disorder and violence, though, since it’s focused on studying borderline personality disorder in perpetrators, it’s not reporting whatever the picture may be among people with borderline personality disorder who aren’t violent towards others. For instance, this literature review, in contrast, reports that

Results indicate that BPD does not appear to be independently associated with increased risk of violence in the general population. History of childhood maltreatment, history of violence or criminality, and comorbid psychopathy or antisocial personality disorder appear to be predictors of violence in patients with BPD.

(So, if I put the studies together, people with borderline personality disorder aren’t more likely to be violent if they don’t have comorbid antisocial personality disorder, but often have comorbid personality disorder?)

Antisocial personality disorder (unsurprisingly, since antisocial behavior is baked into the definition of the disorder) is the biggest risk factor for violence, of the personality disorders.

Antisocial personality disorder increases the risk over 10-fold in men and over 50-fold in women.

At any rate, the overall picture appears to be that, yes, mental illness does increase the risk of violent behavior, but no, for most mental illnesses that increase in risk probably isn’t nearly as much as most people think, and that most of it involves young men with a mix of substance abuse and antisocial personality disorder.

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