Though violent behavior is the exception rather than the rule among people
with schizophrenia, one large study found that positive psychotic symptoms
such as persecutory ideation and grandiosity were associated with an increased
risk of serious violence.
In contrast, negative symptoms such as passivity and social withdrawal were
associated with a decreased risk of violent behavior.
"I think these findings reinforce the view that violence risk
reduction should be an important goal and component of community-based
treatment for schizophrenia and that risk reduction needs to focus on clinical
as well as nonclinical factors that may contribute to violence," one of
the study's investigators, Marvin Swartz, M.D., told Psychiatric
News. Swartz is a professor and head of the Division of Social and
Community Psychiatry at Duke University Medical Center.
Nonclinical factors related to violence in the sample included residing in
restrictive housing (such as a halfway house, psychiatric hospital, or jail)
or with family, not feeling "listened to" by family members, and a
recent history of police contact.
Data came from baseline interviews of 1,410 people with schizophrenia
enrolled in the National Institute of Mental Health Clinical Antipsychotic
Trials of Intervention Effectiveness (CATIE) study.
The CATIE study was a randomized trial conducted between January 2001 and
December 2004 at 56 clinical sites in 24 states to investigate treatment
effectiveness and outcomes among patients with schizophrenia.
Each study site screened inpatients and outpatients for study eligibility.
Those who were deemed to be appropriate for participation had adequate
decision-making capacity and were receiving suboptimal treatment with
antipsychotic medications due to problems with efficacy or tolerability.
During a baseline assessment and before the patients were randomized to
experimental treatments for the CATIE study, lead investigator Jeffrey
Swanson, Ph.D., and colleagues assessed the patients for violent behavior in
the prior six months. He is an associate professor in the Department of
Psychiatry and Behavioral Sciences at Duke.
To assess the generalizability of the sample, Swanson compared participants
with a "quasi-random" sample of 1,413 patients enrolled in the
Schizophrenia Care and Assessment Program, an observational study of
schizophrenia treatment in the United States.
Though the CATIE sample had a lower proportion of minority patients, the
two samples were similar in other demographic characteristics, age, and a
variety of clinical characteristics.
The similarities provide "some confidence that the CATIE project's
randomized, controlled-trial design did not result in a biased selection of
more severely ill and impaired patients," the authors noted.
They used the MacArthur Community violence Interview to measure minor and
serious violence. Researchers defined minor violence as a simple assault
without injury or weapon use (shoving or slapping another person, for example)
and serious violence as assault using a lethal weapon or resulting in injury,
threat with a lethal weapon, or sexual assault.
Researchers gathered information on violent acts by the subjects through
patient self-reports and family collateral information (when available).
Researchers also assessed patients at baseline for factors such as
available social support, severity of illness, and awareness of mental health
problems, among others. They also used the Structured Clinical Interview for
Axes I and II of DSM-IV Disorders—Patient Edition to confirm
schizophrenia diagnoses and assess childhood conduct problems.
In addition, they used the Positive and Negative Syndrome Scale (PANSS) to
rate severity of psychotic symptoms.
Among the 1,410 patients, the six-month prevalence of any violence was 19.1
percent: 219 patients (15.5 percent) reported minor violence, while 51 (3.6
percent) reported serious violence.
Swanson found that serious violence was associated with several clinical
and nonclinical factors.
For instance, those who scored above the median on the PANSS for positive
psychosis symptoms had 2.71 times the risk for serious violence as those with
Patients who scored above the median for negative psychotic symptoms had
about a quarter of the risk as those who scored below this point.
People with suspiciousness and persecutory delusions also had an increased
risk of engaging in serious violence (odds ratio 1.46, p<.001), as did
those who responded to hallucinations (odds ratio 1.43, p<.001).
Also, serious violence was significantly associated with grandiosity (odds
ratio 1.31, p=<.001) and excitatory symptoms (odds ratio 1.30, p=.02).
In addition, the findings showed that 27.5 percent of those who committed
serious violence were arrested, and 16.1 percent of those with minor violence
were arrested for some crime in the previous six months. Arrest data were
gathered by self-report.
Swanson told Psychiatric News that he thought that positive
psychotic symptoms may lead to violence in several ways: "A person with
a severe thought disturbance may hear voices directing him or her to attack
someone else," he said. With persecutory delusions, "a person may
act on a false perception of threat of harm from someone" in which case"
a violent act might seem like self-defense from the distorted
perspective of the person with psychosis."
Younger age, childhood conduct disorder problems, and a history of arrests
were nonclinical factors associated with serious violence, the researchers
Nonclinical factors associated with minor violence included limited or no
vocational activity, residing in "restrictive" housing with
family, and not feeling "listened to" by family members.
"Studies show that when violent behavior occurs, it tends to involve
family members and acquaintances much more often than strangers,"
Swanson noted. "People with severe mental illness may also experience
emotional conflict within family relationships.. .that can contribute to the
risk of violence."
He speculated that a "cause-and-effect connection" might play a
role in the link between minor violence and lack of a job. "Being
unemployed and having no meaningful work to do—especially over a long
period of time—can be stressful and may indirectly increase risk of
assaultive behavior in people with schizophrenia."
Swanson emphasized that the majority of patients with schizophrenia have
positive psychotic symptoms but do not engage in violent behavior.
He acknowledged that "serious violence [among people with
schizophrenia] may be unlikely, but it's a bad thing when it happens"
and that clinicians and advocates for patients' rights may have different
interpretations of the study findings.
"Psychiatrists worry about patient violence not because it's
especially common, but in part because of clinicians' legal liability for
adverse, but rare, outcomes of their treatment decisions."
In contrast, patients' rights advocates, who often oppose involuntary
treatment, may be concerned because national surveys have shown that the"
majority of the public believes (erroneously) that mentally ill people
are generally dangerous," and this belief could be used to justify legal
strategies for overriding people's right to refuse mental health treatment,
He noted that homicides or other serious violent acts committed by a person
with schizophrenia usually become "banner headlines" in newspapers"
even if other potential factors are involved" in the violent act."
you will not read a companion story about the thousands of other people
with mental illness in the same city who never did anything
The findings, he continued, "reinforce the view that violence
risk-reduction should be an important goal of community-based treatment for
schizophrenia" and that "risk reduction needs to focus on clinical
and nonclinical factors that may contribute to violence."
Further research in this area, he said, should focus on studying violence
in people with mental illness from a developmental perspective, "taking
into account the complex interactions between social environment, features of
psychiatric illness, and personal characteristics of individuals as they
change over time."
The study was funded by the Foundation of Hope, an organization in Raleigh,
N.C., that promotes research into causes and treatments of mental illness.
An abstract of "A National Study of Violent Behavior in
Persons With Schizophrenia" is posted at<http://archpsyc.ama-assn.org/cgi/content/abstract/63/5/490>.▪