Ten years ago the MacArthur Violence Risk Assessment Study sought to
understand the relationship between mental illness and perpetration of
The principal finding—that there was no significant difference
between the prevalence of violence by patients with mental illness who were
without symptoms of substance abuse and the prevalence of violence by others
living in the same neighborhoods who were also without symptoms of substance
abuse—has been cited by mental health advocates as "proof"
that the popular conception that mentally ill individuals are prone to
violence is a myth.
Since then, additional articles, book chapters, and a book about the
MacArthur study have appeared, adding new data about a topic that engages the
attention of professionals, policymakers and the general public.
While many mental health advocates have championed the report for
demonstrating that patients are not more dangerous than the general
population, the study has also drawn critics. Among these are psychiatrist
Fuller Torrey, M.D., and attorney Jonathan Stanley, J.D., who engage in a
printed "debate" in this month's Psychiatric Services
with MacArthur study authors John Monahan, Ph.D., and Henry Steadman, Ph.D.,
and their co-authors (see Major Problem Often Overlooked When Linking
Torrey and Stanley raised "six points of interest"—about
methodology, interpretation, and generalizability of results—to which
Monahan and Steadman responded in turn.
In the six points, and during an interview with Psychiatric News,
Torrey emphasized that data about the value of treatment were not included in
the original study—though they appeared later in book form—and
that mentally ill individuals who receive and are compliant with treatment are
not more dangerous than others in the population.
But he said that untreated mental illness is a matter of legitimate concern
for public safety.
"The authors of the MacArthur study can't be faulted for the way some
people have interpreted the results, but it has been popularly cited as
evidence that the mentally ill are not more dangerous than the general
public," Torrey told Psychiatric News. "In this way, some
advocates hope to reduce the stigma surrounding mental illness.
"But in our view, it's the violence that causes the stigma," he
Torrey is executive director of the Stanley Medical Research Institute and
president of the Treatment Advocacy Center, an organization that advocates for
laws permitting involuntary treatment of patients with severe mental
In the Psychiatric Services article, Torrey and Stanley pointed
out that in the MacArthur sample of 951 psychiatric patients, three patients
killed six people—a rate much higher than the 5.6 homicides per 100,000
in the U.S. general population.
Monahan and Steadman responded that selecting a few individual cases is not
a systematic assessment of violence rates.
In an interview with Psychiatric News, Monahan reasserted his
confidence in the study's findings, though he believes that some aspects of
the study have been "overstated" by those advocating one or
another policy position.
"The study has been cited by some advocates as proof that the
mentally ill are no more dangerous than the general population, and as proof
by other advocates that treatment reduced violence," Monahan said."
We think both positions overstate what the study shows."
"What we found is that violence among the mentally ill is mediated by
substance abuse," Monahan said. "We have confidence in the
validity of our original findings."
Past APA President Paul Appelbaum, M.D., who was also a member of the
MacArthur study group, said he believes interpretation of the MacArthur
findings are typically a function of one's beliefs about how best to deal with
the problem of stigma.
"There are some facts about violence and mental illness that everyone
can agree on," Appelbaum told Psychiatric News. "People
with mental illness account for only a small percentage of violence in this
country—2 percent, maybe 3 to 5 percent. But no one has ever suggested
that it might be more than 5 percent. That means at least 95 percent of the
violence is not committed by mentally ill people. Some patients become violent
but most do not.
"The rate of violence among the population of people who are mentally
ill is greater than among the general population, and the risk of violence is
greater with substance abuse," Appelbaum said. "Some studies have
found that if you control for substance abuse, there is no difference, but
other studies have done that and found that while they have some decline, it
doesn't completely explain the variance.
"About these facts everyone conversant with the data can
agree," he continued. "The disagreement comes from differences of
opinion about how the findings should be used for policy purposes. Some people
believe we can get more funding for treating mental illness by emphasizing the
potential for violence. These people tend to believe that voluntary treatment
for severe mental illness is not enough and that we need to have an increase
in coercive methods."
Appelbaum said he was "dubious" about the long-term effect of
emphasizing violence. "It increases stigma of mental illness and compels
people to want to spend money on containment but not on treatment and
Regarding the value of treatment, Appelbaum said he believed it was
generally true that treatment diminishes the risk of violence.
"But you can't draw that conclusion from the MacArthur study, because
the study wasn't a randomized, controlled trial," he said."
Although people who got more treatment had lower rates, one can't rule
out that what we are looking at is not causal. Those who are 'good actors' are
more likely to be compliant, and those who are the 'bad actors'—who may
be more likely to be violent—may also be less likely to be
Data from the MacArthur Violence Risk Assessment Study was first
published in May 1998 in "Violence by People Discharged From Acute
Psychiatric Inpatient Facilities and by Others in the Same
Neighborhoods," posted at <http://archpsyc.ama-assn.org/cgi/content/abstract/55/5/393>.