New analyses of violent behavior in patients with schizophrenia have traced
propensity for violent behavior in certain patients to childhood conduct
problems before psychotic symptoms emerged.
A study published June 30 in the online version of Law and Human
Behavior by Jeffrey Swanson, Ph.D., an associate professor of the
Department of Psychiatry and Behavioral Sciences at Duke University, and
colleagues suggests a pathway to violent behavior in schizophrenia linked to a
developmental pattern of early antisocial characteristics.
The authors reviewed data on 1,445 adult schizophrenia patients from the
Clinical Antipsychotic Trials for Intervention Effectiveness (CATIE) study and
looked for associations between their history of childhood conduct problems
and prevalence of violent behavior within the six months before study
The definition of violent behavior included both minor (simple battery
without injury or weapon use) and serious violence (assault using a lethal
weapon or resulting in injury, any threat with a lethal weapon in hand, or any
sexual assault). History of childhood conduct problems before age 15 was
defined as positive response to at least two of the six questions designed to
assess defiant antisocial characteristics in children.
The rate of violence within the preceding six months was 28.2 percent among
the 488 patients who had a history of childhood conduct problems. This was
twice the rate of violence (14.4 percent) among the 956 patients without a
history of childhood conduct problems (none or one positive response to the
six assessment questions); the difference was statistically significant.
CATIE was a national study of the cost-effectiveness of antipsychotic
medications conducted from 2001 to 2004 at 56 sites across the United States
and funded by the National Institute of Mental Health (Psychiatric
News, April 6, March 16). The patients studied were adults aged 18 to 65
who met DSM-IV criteria for schizophrenia, were not experiencing the
first episode of schizophrenia, and were treated with oral medications.
Additional analyses of the correlation between violence and childhood
antisocial characteristics revealed risk-factor patterns associated with
violence in the two patient groups.
In the patients with childhood conduct problems, for example, there was a
statistically significant association between violence and substance use as
well as a substance abuse or dependence disorder, but not between violence and
positive psychotic symptomatology as measured by higher Positive and Negative
Syndrome Scale positive scores. (Substance use, as opposed to abuse or
dependence, refers to alcohol or illicit drug use that does not cause
significant impairment, according to a study of CATIE data by the same
researchers in the May 2006 Archives of General Psychiatry).
In the patients without childhood conduct problems, violence was
statistically significantly associated with substance abuse or dependence
disorder only and with positive psychotic symptomatology, but not with
substance use. The two groups of patients did share several other risk factors
also significantly associated with violence, including younger age, lack of
substantial vocational activity, residing with family or other relatives, and
recent involvement with the police.
The researchers discussed two theories that may explain the findings.
First, the childhood antisocial tendency may be an early sign of an underlying
pathology in a subgroup of schizophrenia patients prone to violence in
adulthood. Or it may be that a subtype of patients has characteristics of
comorbid antisocial personality disorder separate from psychosis.
"This study is an important contribution to the understanding of
pathogenesis of violent behavior in schizophrenia patients. It is consistent
with previous observations that violent patients with schizophrenia have high
ratings on the psychopathy scale and that only about 20 percent of violent
incidents in psychotic inpatients is directly attributable to positive
symptoms," commented Jan Volavka, M.D., Ph.D., a professor emeritus of
psychiatry and a research professor of psychiatry at New York University
School of Medicine and the author of the book Neurobiology of
"The study indicates that much of the violence in schizophrenia is
not directly related to psychosis. It is therefore not likely to respond to
antipsychotic medication," Volavka said. Although treatment for violent
behavior in this subpopulation is not well established, he pointed to previous
studies that suggest long-term, cognitively based, behavioral treatment may be
helpful to some schizophrenia patients with persistent violent behavior not
directly related to psychotic symptoms.
An abstract of "Alternative Pathways to Violence in Persons
With Schizophrenia: The Role of Childhood Antisocial Behavior Problems"
is posted at<www.springerlink.com/content/c718739702076675/?p=0d39f6b1aa8847eab14d224ef6969fa1&pi=5>.▪