In the 1830s, jails were an all-purpose solution for a lot of issues. Inmates lived in squalor and people truly did not want to be there so there was a lot less crime. The downside was that nobody really cared about the people who did not belong there, like those with 'retardation' who had been abandoned, or people who were mentally ill but not criminals.

Dorothea Dix was the activist whose efforts led to the first generation of American mental asylums. At the age of 39, she happened to visit a local jail to do a Sunday school sermon for female inmates. She found that criminals, retarded people and the mentally ill all lived together in terrible, unheated conditions. When she asked why, she was told  "the insane do not feel heat or cold"(Viney&Zorich, 1982). Not exactly evidence-based.

She had no interest in defending criminals but she began a radical campaign to stop treating mental illness as a crime. She went to court to get conditions improved and won. Then she went to the legislature and convinced them that mentally ill people were not criminals and could be fixed with proper treatment. She succeeded, so then she went to more states and then she went to the US Congress to lobby for federal oversight. Then she went to Europe and did the same thing there. Her work resulted in taking mental health patients out of jails and putting them in hospitals, which was obviously a good thing. She did not believe mental illness could not be fixed.

Today, the cultural scenario is much different. Experts in the 20th century began to say that asylums, a dramatic improvement over jails, were the problem. Horror stories about abuse led to a 90% reduction in mental health facilities, instead the trend became outpatient care and drugs. In 1955, there were almost 560,000 patients in mental hospitals and now there are about 35,000. What also happened after the decline in asylums? Mentally ill people are convicted of crimes and end up in jails, just like when Dorothea Dix first visited a local facility in 1841. 

Asylums are mostly known about due to horror movie imagery and click-bait stories about "chilling" institutions. As a result, mentally ill people end up in jail, and somewhere in psychology heaven Dorothea Dix is doing a giant facepalm. Danvers State Insane Asylum, Massachusetts. Closed since 1992. Link:

But the reasons now are different. Mental illness has become such an exculpatory part of the American cultural landscape that it is used to absolve all kinds of things - pleading mental illness is a common defense. Some even now contend that many criminals are not actually criminals but are instead mental health patients - that we have gone back to the time of Dorothea Dix, when mentally ill people were just thrown in jail. A recent report from Treatment Advocacy Center says there are 10 times more people with mental illness in state prisons and county jails (207,000 and 49,000, respectively) than there are in state mental hospitals (35,000). A jail is the largest single “mental institution” in 44 of 50 states while beds in mental hospitals have declined in the last 60 years. 

That's a provocative claim, it was dutifully rehashed by people who want to feel like they care about the mentally ill, in the spirit of Dorothea Dix. Few stated the painfully obvious sociological aspects of this, they just took those numbers at face value and used it as cultural criticism. The real issue is a bigger problem because it doesn't impact just the 0.1% who may or may not be criminals that would not be criminals if they had proper mental health care. 

Dorothea Dix. Link:

What curves match the increase in prisoners with psychological diagnoses, real or not, in the last 50 years? The trend toward everyone having a psychological diagnosis. Psychology has become less scientific and more about creating new diagnoses than solving mental health problems - that has meant it's been easy to find a psychologist willing to testify that a criminal has a mental health disorder, which attorneys have been happy to exploit if it is remotely plausible. Even if they don't get their clients absolved, the diagnosis is still part of the public record and therefore shows up in claims about how most criminals instead belong in a mental health hospital. Medicine stopped using symptom-based diagnosis 50 years ago yet it is still common in psychology and psychiatry.

Given the willingness to diagnose someone as mentally ill, how do we know the difference between criminals and people who aren't inclined to commit crime with treatment? That is the problem, we don't. There's no way to know how many of the people in jail with mental health issues actually have them - beyond the fact that engaging in rape, murder, assault and robbery is not something mentally healthy engage in - because almost everything can be a mental illness. The loose definition of autism spectrum disorder alone means an overwhelming majority of criminals have it. Parents of most children with autism can't imagine their children being violent criminals - they inherently lack the ability to be mean, in a lot of cases - yet a confirmed criminal is absolved of guilt if they are portrayed as mentally ill.

Without clear definitions, and not a DSM 5 mishmash of constituency consensus lobbying by people who want more things covered by health insurance, we can't make any progress in helping those with mental illness. Real definitions would tell us things that could actually help, like if young men or minorities are in jail more because of underlying issues that can't be blamed on the president's economic policies or the NRA's gun policies or everything else invoked by partisan groups.

Dr. Thomas Insel, M.D., head of the National Institute of Mental Health, believes that a return to asylums are not the answer, though he clearly has respect for Dorothea Dix and her efforts to create asylums, but the other institutional solutions, hospitals and jails, require people there to become a 'jack of all trades' and try to solve one of psychology's most vexing puzzles - criminal behavior. Advocates say criminals with a mental illness diagnosis should be released and have managed care, but how can we determine which people are safe for society? Since homelessness correlates strongly with mental illness, aren't people freed from jail likely to fall into that grouping where, without medication, things could get even worse?

We have so many more mental patients in jails not because we have returned to the America of the 1830s, where the mentally ill are just thrown in jail so we don't have to think about them, but because mental illness has been turned into a scientifically subjective loophole and therefore part of a cultural agenda.