# Is there a link between mental illness and violence? **URL:** \ **Category:** Great Debates\ **Created:** [September 1, 2017, 10:30pm UTC](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275 "2017-09-01T22:30:05Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![protoboard](https://avatars.discourse-cdn.com/v4/letter/p/fbc32d/32.png) [@protoboard](https://boards.straightdope.com/u/protoboard)\ **Post date:** [September 1, 2017, 10:30pm UTC](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275/1 "2017-09-01T22:30:05Z")
I’ve heard conflicting reports. Obviously, the politically correct idea is that violence is caused by people’s free choices and rarely if ever by mental illness. However, mental illness is known to be connected to at least one violent act - suicide. Some researchers say that mental illness has absolutely no link to violent behavior, and when mentally ill people are violent drug use is usually involved. Of course, it’s also likely mentally ill drug abusers are more mentally ill than mentally ill people who are sober, so how much of it is the drugs is debatable. I’ve heard others say however that schizophrenia can lead to violent behavior in certain situations (even without substance abuse), and there are individual cases where mental illness clearly _did_ lead to violence, for example the Greyhound bus beheading in Canada. My guess would be that certain forms of mental illness could lead to violence in some individuals, but that overall the link between mental illness and violence, while not non-existent, is overestimated by the general public. ---
**Author:** ![sweat209](https://avatars.discourse-cdn.com/v4/letter/s/9fc348/32.png) [@sweat209](https://boards.straightdope.com/u/sweat209)\ **Post date:** [September 1, 2017, 10:53pm UTC](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275/2 "2017-09-01T22:53:07Z")
> [@protoboard](#): > > I’ve heard conflicting reports. Obviously, the politically correct idea is that violence is caused by people’s free choices and rarely if ever by mental illness. However, mental illness is known to be connected to at least one violent act - suicide. > > Some researchers say that mental illness has absolutely no link to violent behavior, and when mentally ill people are violent drug use is usually involved. Of course, it’s also likely mentally ill drug abusers are more mentally ill than mentally ill people who are sober, so how much of it is the drugs is debatable. > > I’ve heard others say however that schizophrenia can lead to violent behavior in certain situations (even without substance abuse), and there are individual cases where mental illness clearly _did_ lead to violence, for example the Greyhound bus beheading in Canada. > > My guess would be that certain forms of mental illness could lead to violence in some individuals, but that overall the link between mental illness and violence, while not non-existent, is overestimated by the general public. In old days people thought mental illness where possessed by evil spirits is what caused mental illness. Now days people think chemical imbalance or childhood experiences is cause mental illness. Some people today even hold other view so called weak character or immoral person. No one knows what causes ADHD, split personality disorder, phobia, anxiety,fear, obsessive compulsive, social deviant, antisocial personality disorder, alcoholism, addiction, drug addiction, manic, personality disorder just to name some. In the old days person should be locked up in mental hospital, exorcism done on him or her or hole cut in the person brain to allow evil spirits out or worse burning at the stake because they are evil person? There no test to even say you have this mental illness!!! It base on symptoms alone!!! No blood work or scan!!! Some people say physiology is pseudoscience because cause of most mental illness is unknown. ---
**Author:** ![Kimera757](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kimera757/32/3765_2.png) [@Kimera757](https://boards.straightdope.com/u/Kimera757)\ **Post date:** [September 1, 2017, 11:51pm UTC](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275/3 "2017-09-01T23:51:48Z")
From what I’ve read, the mentally ill are more likely to be violent but _much_ more likely to be victims of violence. Here’s a link about the latter: [https://news.ncsu.edu/2014/02/wms-desmarais-violence2014/](https://news.ncsu.edu/2014/02/wms-desmarais-violence2014/) Of course, there’s such a wide variety of mental illnesses that the studies don’t tell us much. I’m sure people suffering from many mental illnesses are _less_ likely to be violent, and people suffering from certain mental illnesses are more likely to be violent. ---
**Author:** ![Reddy\_Mercury](https://avatars.discourse-cdn.com/v4/letter/r/43a26b/32.png) [@Reddy\_Mercury](https://boards.straightdope.com/u/Reddy_Mercury)\ **Post date:** [September 2, 2017, 1:00am UTC](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275/4 "2017-09-02T01:00:09Z")
It depends on the mental illness. I really doubt someone suffering from major depression for example would be inclined to do violence to anyone except perhaps themselves. A person who is suffering from paranoid schizophrenia and hearing voices might be more inclined. I think it’s a sad stigma of the mentally ill that a person with a mental illness is viewed with suspicion, basically as being someone to wear kid gloves around. ---
**Author:** ![igor\_frankensteen](https://avatars.discourse-cdn.com/v4/letter/i/839c29/32.png) [@igor\_frankensteen](https://boards.straightdope.com/u/igor_frankensteen)\ **Post date:** [September 2, 2017, 8:08pm UTC](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275/5 "2017-09-02T20:08:40Z")
> [@protoboard](#): > > I’ve heard conflicting reports. Obviously, the politically correct idea is that violence is caused by people’s free choices and rarely if ever by mental illness. However, mental illness is known to be connected to at least one violent act - suicide. > > Some researchers say that mental illness has absolutely no link to violent behavior, and when mentally ill people are violent drug use is usually involved. Of course, it’s also likely mentally ill drug abusers are more mentally ill than mentally ill people who are sober, so how much of it is the drugs is debatable. > > I’ve heard others say however that schizophrenia can lead to violent behavior in certain situations (even without substance abuse), and there are individual cases where mental illness clearly _did_ lead to violence, for example the Greyhound bus beheading in Canada. > > My guess would be that certain forms of mental illness could lead to violence in some individuals, but that overall the link between mental illness and violence, while not non-existent, is overestimated by the general public. There is far more confusion than coherence within and behind this question. Short answer: no, there is no “link” such as you clearly imagine, between mental illness and violence. And by the way, it has nothing whatsoever to do with"political correctness," it has ENTIRELY to do with accurate use of words, and accurate understanding of facts, and accurate understanding of science. Some hints: - are all mentally ill people violent? No. - are all violent people mentally ill? No. - has science determined a specific way to PHYSIOLOGICALLY identify all mental illness? No. - is mental illness defined differently in law, than in medicine? Yes. - and so on. ---
**Author:** ![monstro](https://avatars.discourse-cdn.com/v4/letter/m/ba9def/32.png) [@monstro](https://boards.straightdope.com/u/monstro)\ **Post date:** [September 2, 2017, 8:49pm UTC](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275/6 "2017-09-02T20:49:19Z")
I don’t know if there is a link, but I would not be surprised if there is. I believe that mental illness is a real thing. But it’s not clear-cut. Is someone with a personality disorder sick in the same way that someone with generalized anxiety disorder is? I think they are, but many people don’t agree. Do people with ADHD or autism suffer from a mental illness? Or do they suffer from a neurological disorder? Personally, I don’t see why it matters, but lots of people think it is an important distinction. If someone is suffering from a chronic mental illness that prevents them from keeping a job and they end up turning to armed robbery to support themselves, do we blame their untreated mental illness? Or poverty? Futhermore, I think there are a lot of people with “issues” out there who commit acts of violence, but don’t meet any formal diagnosis. Like, I think my father has an unusually quick temper. When I was a kid, any little thing would set him off, sometimes violently. I don’t believe he’d fit any DSM-V diagnosis, but is he mentally “healthy”? I don’t know. In short, I think “mental illness” is too broad of a term to be useful. ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [September 2, 2017, 9:37pm UTC](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275/7 "2017-09-02T21:37:00Z")
It depends on the mental illness. Anorexia or Depression? Probably not likely to be violent. Intermittent explosive disorder or borderline personality disorder? Probably more likely. FWIW, the seriously mentally ill are more likely to be victims of violence because they engage in socially inappropriate behavior, and society doesn’t really value their safety. ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [September 2, 2017, 10:48pm UTC](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275/8 "2017-09-02T22:48:17Z")
> [@sweat209](#): > > Some people say physiology is pseudoscience because cause of most mental illness is unknown. Those people who say that are idiots. Physiology is well-documented via the scientific method. There’s more to learn, but it’s hard science. ---
**Author:** ![igor\_frankensteen](https://avatars.discourse-cdn.com/v4/letter/i/839c29/32.png) [@igor\_frankensteen](https://boards.straightdope.com/u/igor_frankensteen)\ **Post date:** [September 3, 2017, 12:40am UTC](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275/9 "2017-09-03T00:40:34Z")
Well, let me backtrack just a little. If you are one of those horrible people who believes it every time someone publishes a story claiming there is a “statistical link” between two seemingly unrelated factors, even when you learn that the “statistical link” is a less-than-one-percent-correlation, then the answer for you, would be “yes, there is a link between violence and mental illness.” Unfortunately, the same statistics could be read to claim that there is a “statistical link” between violence and ice cream sales as well. Though I wouldn’t be surprised if there really IS a statistical link between road rage incidents, and the price of gasoline. ---
**Author:** ![Sage\_Rat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sage_rat/32/399_2.png) [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)\ **Post date:** [September 3, 2017, 1:38am UTC](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275/10 "2017-09-03T01:38:01Z")
[http://www.treatmentadvocacycenter.org/evidence-and-research/learn-more-about/3695](http://www.treatmentadvocacycenter.org/evidence-and-research/learn-more-about/3695) > **[Care of the Mentally Ill in Prisons: Challenges and Solutions](https://jaapl.org/content/35/4/406)** > > So, where did all the \[state hospital\] patients go?—Emanuel Tanay, MD\[1\]\[1\] Jails and prisons have become the mental asylums of the 21st Century—CNN\[2\]\[2\] > > The United States has the highest rate of adult incarceration among the developed countries,... The thing about statistics is that they don’t work the way people think. Consider these two statements: 1. You’re almost 20x more likely to be attacked by a person with NO mental illness than one who has one. 2. People with mental illnesses are 5x more likely to be violent than a person with no mental illness. In our minds, these statements are in direct conflict. And let me note, real quick, that while the cites above are real cites, the two statements above are just manufactured for the sake of illustration and are unrelated to the cites. But so let’s say (again, using manufactured numbers) that 1 in 100 people are mentally ill. In a population of 10,000 people, there would be 9,900 people with no mental illnesses and 100 people with a mental illness. We’ll say that 1 in 100 normal people might act in a criminally violent manner during their life. So from our population of 9,900 people, that would be 99. The rate of mentally people, who are 5x more likely to be violent, would be 5 in 100. So, that would mean that there are 5 criminally violent people in our population of 10,000 people. In statement 1, I said that you’re more likely to be attacked by a mentally stable person. Well yes, 99 mentally stable people will have been violent compared to 5 mentally instable people who were, so this is true at an almost 20x rate. And, obviously statement 2 is true, since it’s how we arrived at our numbers to begin with. At the end of the day, I don’t know what the real numbers are, but based on the prison rates and noting that it does not match the general population, I think it’s reasonable to say that a mentally ill person is more likely to be violent than a mentally stable person. But that does not mean that a mentally ill person is likely to be violent, nor that they are a significant percentage of all violent persons. ---
**Author:** ![PastTense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pasttense/32/14550_2.png) [@PastTense](https://boards.straightdope.com/u/PastTense)\ **Post date:** [September 3, 2017, 1:39am UTC](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275/11 "2017-09-03T01:39:05Z")
> [@](#): > > From the Department of Justice’s Survey of Inmates in State and Federal Correctional Facilities (2004) and Survey of Inmates in Local Jails (2002) indicate that the rate of mental health problems differ by the type of correctional facility. In this study a mental health problem was defined as receiving a clinical diagnosis or treatment by a mental health professional. Inmates in local jails had the highest prevalence of mental problems, **with nearly two thirds of jail inmates (64.2 percent) satisfying the criteria for a mental health problem currently or in the previous year**. > **[Statistics](https://www.nimh.nih.gov/health/statistics)** > > NIMH statistics pages include statistics on the prevalence, treatment, and costs of mental illness for the population of the United States, in addition to information about possible consequences of mental illnesses, such as suicide and disability. ---
**Author:** ![coffeecat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/coffeecat/32/3405_2.png) [@coffeecat](https://boards.straightdope.com/u/coffeecat)\ **Post date:** [September 3, 2017, 3:00am UTC](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275/12 "2017-09-03T03:00:11Z")
That could be because the stress of jail drives people crazy, or even because mentally ill criminals are less able to avoid arrest and/or conviction. ---
**Author:** ![Beckdawrek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beckdawrek/32/3647_2.png) [@Beckdawrek](https://boards.straightdope.com/u/Beckdawrek)\ **Post date:** [September 3, 2017, 11:08pm UTC](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275/13 "2017-09-03T23:08:19Z")
My father was in the management business of rental properties…some were subsidised by the government…so the y had to lease to mentally ill with no discrimination…it was understood (under the table)to never lease an upper floor apartment to schizophrenic people.dont know why tho’ ---
**Author:** ![protoboard](https://avatars.discourse-cdn.com/v4/letter/p/fbc32d/32.png) [@protoboard](https://boards.straightdope.com/u/protoboard)\ **Post date:** [September 4, 2017, 7:13am UTC](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275/14 "2017-09-04T07:13:34Z")
> [@igor\_frankensteen](#): > > - are all mentally ill people violent? No. > > - are all violent people mentally ill? No. I don’t think anyone who posits a link between mental illness and violence would make such a bold claim. There could be a link if certain kinds of mental illness make violence more likely. Obviously that doesn’t mean all mentally ill people are doomed to be violent. ---
**Author:** ![sweat209](https://avatars.discourse-cdn.com/v4/letter/s/9fc348/32.png) [@sweat209](https://boards.straightdope.com/u/sweat209)\ **Post date:** [September 4, 2017, 9:06pm UTC](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275/15 "2017-09-04T21:06:09Z")
> [@monstro](#): > > I don’t know if there is a link, but I would not be surprised if there is. > > I believe that mental illness is a real thing. But it’s not clear-cut. Is someone with a personality disorder sick in the same way that someone with generalized anxiety disorder is? I think they are, but many people don’t agree. Do people with ADHD or autism suffer from a mental illness? Or do they suffer from a neurological disorder? Personally, I don’t see why it matters, but lots of people think it is an important distinction. If someone is suffering from a chronic mental illness that prevents them from keeping a job and they end up turning to armed robbery to support themselves, do we blame their untreated mental illness? Or poverty? > > Futhermore, I think there are a lot of people with “issues” out there who commit acts of violence, but don’t meet any formal diagnosis. Like, I think my father has an unusually quick temper. When I was a kid, any little thing would set him off, sometimes violently. I don’t believe he’d fit any DSM-V diagnosis, but is he mentally “healthy”? I don’t know. > > In short, I think “mental illness” is too broad of a term to be useful. **But that thing!!!** people that are born have free choice to make choice in life be it good or bad. If some one has mental illness that could interfere with free will. If I tell you that if you rob a bank is bad and you could go to prison!! You have free will? But people who have mental illness like ADHD, split personality disorder, phobia, anxiety,fear, obsessive compulsive, social deviant, antisocial personality disorder, alcoholism, addiction, drug addiction, manic, personality disorder just to name some. DON’T REALLY have free will because the mental illness could interfere with the free will. ---
**Author:** ![MLS](https://avatars.discourse-cdn.com/v4/letter/m/919ad9/32.png) [@MLS](https://boards.straightdope.com/u/MLS)\ **Post date:** [September 4, 2017, 9:54pm UTC](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275/16 "2017-09-04T21:54:16Z")
I am just now finishing up the book [The Brain Defense](https://www.amazon.com/Brain-Defense-Manhattan-Neuroscience-Courtrooms/dp/1594206333/ref=sr_1_1?s=books&ie=UTF8&qid=1504561926&sr=1-1&keywords=the+brain+defense) by Kevin Davis. It’s a well-researched exploration of neuroscience and criminal justice. The short answer? Sometimes. ---
**Author:** ![Guinastasia](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guinastasia/32/5751_2.png) [@Guinastasia](https://boards.straightdope.com/u/Guinastasia)\ **Post date:** [September 4, 2017, 11:30pm UTC](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275/17 "2017-09-04T23:30:11Z")
> [@sweat209](#): > > **But that thing!!!** people that are born have free choice to make choice in life be it good or bad. If some one has mental illness that could interfere with free will. > > If I tell you that if you rob a bank is bad and you could go to prison!! You have free will? But people who have mental illness like ADHD, split personality disorder, phobia, anxiety,fear, obsessive compulsive, social deviant, antisocial personality disorder, alcoholism, addiction, drug addiction, manic, personality disorder just to name some. > > DON’T REALLY have free will because the mental illness could interfere with the free will. I believe ADHD is neurological, not a mental illness. ---
**Author:** ![sweat209](https://avatars.discourse-cdn.com/v4/letter/s/9fc348/32.png) [@sweat209](https://boards.straightdope.com/u/sweat209)\ **Post date:** [September 5, 2017, 11:18pm UTC](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275/18 "2017-09-05T23:18:09Z")
> [@Guinastasia](#): > > I believe ADHD is neurological, not a mental illness. Well mental illness or not it still asks if these people really have free will and should be in jail or not for crime they done. Some one that steals, break enter, robbery, assault or hurt some some and so on how much free will do they really have. Some one one who have really bad alcoholism that get DUI charge do they really have free will. If their body is really sick and need the booze to deal with the sickness. Some one who have anger management problems that burst out at tiny bit of problem how much free will do they have. ---
**Author:** ![elfkin477](https://avatars.discourse-cdn.com/v4/letter/e/a9a28c/32.png) [@elfkin477](https://boards.straightdope.com/u/elfkin477)\ **Post date:** [September 7, 2017, 12:19am UTC](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275/19 "2017-09-07T00:19:44Z")
> [@Guinastasia](#): > > I believe ADHD is neurological, not a mental illness. Oh, me too…but I have it so I’m not unbiased. The thing is though that the line between mental illness and neurological disorder is blurrier than most people assume. For example, the brains of people who have early onset schizophrenia show distinct neurological differences from the brains of “typical” people, and few people argue against schizophrenia being considered a mental illness. ---
**Author:** ![monstro](https://avatars.discourse-cdn.com/v4/letter/m/ba9def/32.png) [@monstro](https://boards.straightdope.com/u/monstro)\ **Post date:** [September 7, 2017, 3:24am UTC](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275/20 "2017-09-07T03:24:54Z")
The mental illness/neurological disorder divide isn’t helpful, in my opinion. People with neurological disorders (autism, ADHD, Tourette’s Syndrome, Parkinson’s, Huntington’s Disease) very frequently have psychiatric problems (depression, mania anxiety, obsessive-compulsiveness, psychosis, impaired impulse control). Neurological disorders are often treated with psychiatric drugs. You can see brain abnormalities in sufferers of mental illness, while the brains of sufferers of neurological disorders can look “normal”. People with schizophrenia, OCD, autism, and Tourette’s share similar neurological [soft signs](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4980894/). [And depression, autism, and schizophrenia share genetic links](http://www.npr.org/2013/03/01/173271247/-study-depression-autism-and-schizophrenia-share-genetic-links). Moreover, practitioners aren’t really good with diagnosis. Women with autism are frequently misdiagnosed as having borderline PD. Late-onset Huntington’s can look a whole lot like “craziness” than motor disorder. Is someone with Parkinson’s depressed because they are bummed out over their medical issues? Or are they depressed because they are deficient in dopamine? To me, it’s kind of crazy to put boxes around these disorders. We tend to think that neurological disorders are problems with hardware while mental disorders are more like software bugs. But I think we’re a lot more complicated than this. [Next page](https://boards.straightdope.com/t/is-there-a-link-between-mental-illness-and-violence/795275.md?page=2)