New info from Medscape:
violent episodes in schizophrenics associated with drug abuse
August 31, 2009 — An excess risk for violence and violent crime, including homicide, in individuals with schizophrenia and other psychoses is not primarily attributable to the mental illness itself, but rather to comorbid substance abuse, a new meta-analysis suggests.
The systematic review, which is the first of its kind, looked at 20 studies comparing the risk for violence or violent crime in individuals with schizophrenia and other psychoses and in that in the general population. In all, there were 18,423 patients with schizophrenia and other psychoses and 1,714,904 individuals from the general population.
"The main reason we undertook this meta-analysis, which includes all of the studies that look at this issue to date, is because there has been a great deal of uncertainty about whether the relationship between violence and schizophrenia is causal or related to other factors," study investigator Martin Grann, PhD, from the Centre for Violence Prevention, Karolinska Institutet, in Stockholm, Sweden, told Medscape Psychiatry.
"When you look at these 20 studies combined, the pattern is clear that in people with schizophrenia with no alcohol or drug misuse, the risk of violence is insignificant compared with the general population. But when alcohol and drug abuse are added to the equation, then you have a problem," added Dr. Grann.
The study was published online August 11 in PloS Medicine.
People With Schizophrenia Not Dangerous
Among individuals with schizophrenia and other psychoses, 1832 (9.9%) were violent; among the general population, 27,185 (1.6%) were violent. When pooled data from the 2 groups were compared, researchers found that men with schizophrenia had a pooled odds ratio for violence ranging from 1 to 7, compared with those without mental illness.
In women, the odds ratio for violence ranged from 4 to 29 in those with schizophrenia and other psychoses, compared with their counterparts without mental illness.
The effects of comorbid substance abuse was marked with the random-effects odds ratios of 2.1 without comorbidity and an odds ratio of 8.9 with comorbidity, the authors report. Importantly, said Dr. Grann, risk estimates of violence in individuals with substance abuse but without psychosis were similar to those in individuals with psychosis and comorbid substance abuse. The risk for homicide was increased in individuals with psychosis — with or without comorbid substance abuse.
Dr. Grann described the increased risk for violence and homicide among individuals with severe mental illness without substance abuse as "very modest," compared with the general population.
"People with schizophrenia are not dangerous. Individuals without schizophrenia with drug and alcohol abuse are more likely to be violent than individuals with schizophrenia who also have abuse problems. In other words, if a person is an alcoholic or a drug addict, he is less likely to be violent if he also has schizophrenia. So, in this context, you could say schizophrenia is actually protective," said Dr. Grann.
This review, he added, highlights the "critical need" for clinicians to address issues of substance and alcohol abuse in this patient population, an issue he said is often neglected.
Lack of Integrated Care
Asked by Medscape Psychiatry to comment on the findings, Jeffrey A. Lieberman, MD, Lawrence E. Kolb professor and chair of psychiatry at the Columbia University College of Physicians and Surgeons and director of the New York State Psychiatric Institute in New York City, agreed that the study underlines the importance of addressing substance abuse in these patients.
He agreed with Dr. Grann that current management of substance abuse in patients with severe mental illness is not optimal. One of the barriers to effective treatment in the United States, said Dr. Lieberman, is a lack of integrated care.
"Diagnosis is not really a problem. However, as far as treatment is concerned, there is a systemic problem because frequently substance-abuse treatment isn't available in mental healthcare clinical settings, and vice versa. This makes it difficult to provide a broad array of treatments in a single clinical setting, and it is similarly difficult to get patients to go to 2 separate centers for treatment, "he said.
One of the study's limitations, said Dr. Lieberman, is the fact that it did not examine the issue of treatment adherence, which can be a risk factor for violence.
"The features that tend to characterize violence in patients with mental illness are psychotic disorders, treatment nonadherence, and substance abuse. Another influencing factor is homelessness, but the triad of psychotic illness, treatment nonadherence, and comorbid substance abuse point to the highest risk for violent behavior in mentally ill people," he said.
Both Drs. Grann and Lieberman said that more research is needed to determine whether treatments used to address a primary diagnosis of substance abuse are effective in individuals with psychosis who have comorbid substance abuse, and whether such treatments lower the risk for violence.
1: PLoS Med. 2009 Aug;6(8):e1000120. Epub 2009 Aug 11. Links
PLoS Med. 2009 Aug;6(8):e1000112.
Schizophrenia and violence: systematic review and meta-analysis.Fazel S, Gulati G, Linsell L, Geddes JR, Grann M.
Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, United Kingdom. firstname.lastname@example.org
BACKGROUND: Although expert opinion has asserted that there is an increased risk of violence in individuals with schizophrenia and other psychoses, there is substantial heterogeneity between studies reporting risk of violence, and uncertainty over the causes of this heterogeneity. We undertook a systematic review of studies that report on associations between violence and schizophrenia and other psychoses. In addition, we conducted a systematic review of investigations that reported on risk of homicide in individuals with schizophrenia and other psychoses. METHODS AND FINDINGS: Bibliographic databases and reference lists were searched from 1970 to February 2009 for studies that reported on risks of interpersonal violence and/or violent criminality in individuals with schizophrenia and other psychoses compared with general population samples. These data were meta-analysed and odds ratios (ORs) were pooled using random-effects models. Ten demographic and clinical variables were extracted from each study to test for any observed heterogeneity in the risk estimates. We identified 20 individual studies reporting data from 18,423 individuals with schizophrenia and other psychoses. In men, ORs for the comparison of violence in those with schizophrenia and other psychoses with those without mental disorders varied from 1 to 7 with substantial heterogeneity (I(2) = 86%). In women, ORs ranged from 4 to 29 with substantial heterogeneity (I(2) = 85%). The effect of comorbid substance abuse was marked with the random-effects ORs of 2.1 (95% confidence interval [CI] 1.7-2.7) without comorbidity, and an OR of 8.9 (95% CI 5.4-14.7) with comorbidity (p<0.001 on metaregression). Risk estimates of violence in individuals with substance abuse (but without psychosis) were similar to those in individuals with psychosis with substance abuse comorbidity, and higher than all studies with psychosis irrespective of comorbidity. Choice of outcome measure, whether the sample was diagnosed with schizophrenia or with nonschizophrenic psychoses, study location, or study period were not significantly associated with risk estimates on subgroup or metaregression analysis. Further research is necessary to establish whether longitudinal designs were associated with lower risk estimates. The risk for homicide was increased in individuals with psychosis (with and without comorbid substance abuse) compared with general population controls (random-effects OR = 19.5, 95% CI 14.7-25.8). CONCLUSIONS: Schizophrenia and other psychoses are associated with violence and violent offending, particularly homicide. However, most of the excess risk appears to be mediated by substance abuse comorbidity. The risk in these patients with comorbidity is similar to that for substance abuse without psychosis. Public health strategies for violence reduction could consider focusing on the primary and secondary prevention of substance abuse. Please see later in the article for Editors' Summary.
PMID: 19668362 [PubMed - in process]