The blog depression introspection has an entry about this unfortunate post by the Treatment Advocacy Center, an advocacy organization that basically wants to paint some serious mental disorders as medical illnesses and demonize them (in order to increase access to medical treatments for them, yeah, that makes a lot of sense to us too).
When people make outrageous statements like this one,
The CATIE violence study found that patients with schizophrenia were 10 times more likely to engage in violent behavior than the general public (19.1% vs. 2% in the general population).
–TAC
it really makes me mad. It’s clear the author has never actually read the study he’s commenting on (as few people actually bother to read the research, instead preferring to read other people’s summaries of the research, or an abstract). If you’re going to make statements about research, one of the requirements is that you actually read the study you’re commenting on.
As researchers in psychological disorders know, the connections between violence and mental disorders is complex. It’s not a simple, “Well, if you have X diagnosis, you’re Y times more likely to commit violence.” It’s not that at all.
Lots of people like to point to the Swanson (2006) study in the Archives of General Psychiatry as some sort of gold standard in answering the question, “Are people with schizophrenia more violent than others?” It is not. It has specific sampling issues that suggest the sample they had was not a representative sample at all. For instance, here are the exclusion criteria (e.g., these folks were excluded from the study):
Patients were excluded if they were in their first episode of schizophrenia; had a diagnosis of schizoaffective disorder, mental retardation, or other cognitive disorder; had past serious adverse reactions to any of the proposed treatments; had a history of treatment resistance, defined by persistence of severe symptoms despite adequate trials of one of the proposed treatments or prior treatment with clozapine for treatment resistance; were pregnant or breastfeeding; had had a myocardial infarction in the previous 6 months; had a history of or a current QTc prolongation; had uncompensated congestive heart failure; had sustained cardiac arrhythmia, a first-degree heart block, or complete left bundle branch block; or had another serious and unstable medical condition.
That’s a lot of people. Anybody newly diagnosed? Nope, don’t want you. Don’t respond to past treatments? Nope, don’t want you either. Have other mental disorder diagnoses? Generally, we don’t want you. This is not a representative sample. It is what we call a “biased sample.” What influence the bias has in the final results, nobody can say. Except to say that if you start with dirty data, you’re results are going to also be dirty (e.g., biased). The researchers’ sampling methods resulted in 17% of the people screened not being a part of the study for these reasons. That 17% could’ve completely changed the findings of the study (which the researchers acknowledge, “The third limitation is that participants in the CATIE project may not be representative of all persons with schizophrenia”).
A whopping 36% of the study participants had a substance abuse issue. More about this in a moment.
The researchers had baseline violence data on just 42% of their subjects.
Swanson and his colleagues conveniently “redefined” how the assessment measure they used, the MacArthur Community Violence Interview, describes violence. The Interview uses two categories — “violence” and “other aggressive acts.” This is an important distinction, because the researchers who developed the Interview had a clear theoretical construct they pursued and put into an objective interview format. Swanson and his colleagues redefined these two categories to reflect “severe violence” and “minor violence.”
Simple Semantics? Not so, because “other aggressive acts” was a category specifically designed to exclude the concept of “violence” by the original MacArthur researchers. By changing this wording, Swanson and his colleagues could arrive at the astounding 19.2% figure they find (and emphasize) by the end of the study. But this is smoke and mirrors — the 19.2% is an inaccurate representation of the researchers’ own data.
Now, keep in mind that the vast majority of Swanson’s violence indicators come from the patients themselves, without family corroboration — in other words, self-report. How reliable is self-report amongst people with schizophrenia?
It’s also not clear that the study differentiated domestic or family violence from other violence (something most other studies into violence prevalence and incidence generally do). This is an important differentiator, since it has significant policy and public health implications. Should we be increasing domestic and family violence monitoring, treatment and support for this population of people, or should we be cutting off all access to a Constitutional right for all people in this population?
Coming back to the substance abuse question and the sampling issues, the researchers write:
Additional analyses revealed that the sex effect in the final model was influenced by a subgroup of younger women with substance abuse problems and history of arrest. Women in the sample were also more likely to live with family, thereby presumably having more opportunities for physical fights with social network members.
As the researchers themselves note, a small group of people in a sample can create significant results in the data. We’ve long known that people who substance abuse and alcohol abuse issues tend to be more violent than the general population, but this has little to do with traditional mental disorders. (Although classified as such, they are often treated in different facilities by different professionals with specific training.) And the fact they attribute these findings to basically access to family members in order to perpetrate their violence is telling.
At the end of the study, what they did find is that 3.6% of their biased sample self-reported violence (not simply “aggressive acts”). Some have then compared this number to the 30-year-old data gathered from 1980-1985 from the NIMH’s Epidemiologic Catchment Area study, suggesting that data demonstrated a 2% incidence of violence in people without mental disorders. A lot could change in 30 years in terms of incidence of anything in the general population, but we don’t know if that’s still a valid number 30 years later (I’d suggest it’s not). More importantly, the criteria for measuring what is “violence” is different between the two studies — it’s like comparing apples to oranges. You can do it, but it’s not a valid comparison. Just because an anonymous person from the NIMH’s press office did it doesn’t make it valid.
So there you have it. A difference of 1.6% between a biased-sample study and that of 30-year-old data. Significant? Hard to say. I think Swanson and colleague’s words sum it up quite nicely:
Nonclinical variables, such as family coresidence, may affect violence risk in complex ways, either preventing or provoking violent behavior, depending on whether the family environment serves as a protective matrix or an opportunity for aggressive interactions. Consistent with some previous reports, our study presents a complex picture of the linkage between violence, social contact, and social support.
The words of Paul S. Appelbaum (2006) are also appropriate to consider:
The relationship between mental disorders and violence is complex. Among the variables that have been identified as increasing the risk of violence, in addition to psychotic symptoms and substance abuse, are socioeconomic status and even the neighborhoods in which persons with mental disorders reside. No single approach to reducing the risk is likely to be completely effective. And given the relatively modest contribution to the overall risk of violence by persons with mental disorders, the likelihood and magnitude of adverse effects from any intervention must be carefully considered before it is embodied in law.
References
Appelbaum, P.S. (2006). Violence and mental disorders: Data and public policy. Am J Psychiatry 163:1319-1321.
National Institute of Mental Health (1985). Epidemiologic Catchment Area Study, 1980-1985.
Swanson, J.W.; Swartz, M.S.; Van Dorn, R.A.; Elbogen, E.B; Wagner, H.R.; Rosenheck, R.A.; Stroup, T.S.; McEvoy, J.P. & Lieberman, J.A. (2006). A National Study of Violent Behavior in Persons With Schizophrenia. Arch Gen Psychiatry, 63:490-499.
25 comments
[…]Nonclinical variables, such as family coresidence, may affect violence risk in complex ways, either preventing or provoking violent behavior, depending on whether the family environment serves as a protective matrix or an opportunity for aggressive interactions. Consistent with some previous reports, our study presents a complex picture of the linkage between violence, social contact, and social support. […]
Your author writes that The Treatment Advocacy Center is “an advocacy organization that basically wants to paint some serious mental disorders as medical illnesses and demonize them (in order to increase access to medical treatments for them, yeah, that makes a lot of sense to us too).” Are you kidding me? Is the writer suggesting schizohprenia is NOT a “medical illness?” If not, what is it? Demonic possession? Bad parenting? This is 19th Century thinking by a psychologist seeking to legitimize his the esitence of his profession by defaming medical doctors and researchers trying to help victims of severe mental illness and their families. Shame on you.
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Shame on anyone who takes complex concepts, like “schizophrenia” or “bipolar disorder,” and tries turning them into overly simplistic, child-like “brain chemical imbalances,” a theory that’s pretty much already been debunked. There’s no widely available or accepted laboratory test for these disorders, because they are not “medical illnesses” as the term is typically used and defined by physicians and researchers.
They are, however, serious mental disorders which do often require serious attention to treatment issues as well as strong social support systems — things that treat people as the individuals they are.
Have you read the research on the fledgling diagnostic tests for schizophrenia? Not perfect, but very encouraging.
first- some observations. The term ‘violence’ involves a range of behaviors- some continuous with accepted definitions of non-pathological behavior. More refinement in specifying ‘violent behavior’ appears warranted. Are those with mental illness (for example, a psychotic diagnosis) more likely to exhibit sudden physical (behavioral) reaction to a frustrating stimulus? How do we measure the reactions of internalizers? Are physiological and simple behavioral measures adequate to the research question?
Arguing about about medical versus psychological bases for a particular diagnosis (noting that the application of a particular diagnosis is a socially defined activity to begin with) will tend toward treading on well tilled ground. At no time has a particular and specified activity in the brain been ineluctably associated with a particular complex behavior. Perhaps in a future setting, the tiresome distinction between medical and psychological will be broken down- and they (our intellectual descendants) will look back and wonder why we persevered for so long with broken down conceptual machinery …
Do we still need a mind-body distinction?
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I agree. And we should have more recent, up-to-date data about the prevalence of these various kinds of “violence” in the general population, too, because our current datasets are outdated and frankly, not relevant to comparison.
Grohol,
You kicked ass. Thanks for elaborating on it and taking it to the max.
An insightful analysis. Thanks for this.
1. Our CATIE study obtained baseline violence data on about 97% of participants, not 42% as stated by Grohol (and repeated by Erickson.)
2. Regarding generalizability of the sample, we clearly state in the article: “The study excluded first episode patients (who might have been less violent) and wholly treatment-refractory patients (who might have been more violent) and, thus, the findings cannot generalize to such patients . . . 7% of screened patients were excluded for this (or any other) eligibility criterion†(Swanson et al., 2006).
However, that’s not the whole story. We were concerned enough about generalizability that we went to the trouble to systematically compare CATIE participants with a quasi-random sample of 1413 patients enrolled in the Schizophrenia Care and Assessment Program (SCAP), an observational noninterventional study of schizophrenia treatment in usual-care settings in the United States — a study without the exclusion criteria that Grohol mentions. As we explain in the article, the two samples were very similar in their demographic and clinical characteristics — variables that might be considered risk factors for violence. In any event, this issue was addressed to the satisfaction of several demanding independent peer reviewers and editors for the Archives of General Psychiatry.
3. Regarding comparisons of violence rates across different studies: It’s important to note that the ECA violence measure (Swanson et al., 1990; Swanson 1994) included what the MacArthur study would have termed “other aggressive acts” as well as “violence.” Specifically, the ECA measure combined items indicating less serious acts (e.g. ” . . hit or throw things at your wife/husband/partner”) and more serious acts (e.g. “. . . used a weapon like a stick, knife or gun in a fight”). Using this measure, our ECA study found that 13% of persons with schizophrenia residing in the community had been violent within 1 year, compared with 2% of those without mental disorder. The ECA findings are not directly comparable to the CATIE findings, as Grohol notes. However, if one is going to compare them anyway (as Grohol does), the most correct comparison would be between CATIE’s 6-month prevalence rate for schizophrenia patients with any violence (19%), and the ECA’s 1-year rate for community respondents with schizophrenia with any violence (13%). Grohol’s assertion that there is a “difference of [only] 1.6%” between the CATIE schizophrenia and ECA general-community violence rates is specious; this is comparing serious violence in the former with all (minor + serious) violence in the latter. (Forget about apples and oranges; this is more like comparing a grape to a watermelon.)
Grohol also questions the ECA’s “magically low 2% figure” for the general population’s violence rate. Instead, he recommends using the MacArthur study’s “more recent and accurate data — research that uses the exact same violence measure — is readily available via Steadman et al. (1998).” Well, as I’ve noted above, the measures are not, in fact, the “exact same” (although I do think they’re fairly comparable — that is, if one includes “other aggressive acts” in the measure as we did in the CATIE combined index of “any violence”.) But if one insists, as Grohol does, that CATIE and ECA are NOT comparable measure of violence (notwithstanding that he compares them himself, when convenient), then MacArthur and ECA are not comparable either — for the same reason. You can’t have it both ways. (I think Grohol has opened himself to the charge of statistical sophistry here, though perhaps not the more serious crime of intentional academic mendacity!)
But the much bigger problem with using the MacArthur study to estimate the general community violence rate was clearly stated by the study authors themselves:
“Care should also be taken in making patient-community comparisons. We sampled from the census tracts in which the patients resided after discharge. Many of these neighborhoods were disproportionately impoverished and had higher violent crime rates than the city as a whole. We sampled in this manner to control for exposure to environmental opportunities for violence between the patient and the comparison groups. The comparison group was not intended to be an epidemiologically representative sample of the general population of Pittsburgh.†(Steadman et al., 1998).
That’s probably why the MacArthur study found such high rates of “violence” and “other aggressive acts only” in their community sample — 4.6% and 15.1%, or 19.7% combined, in a 10-week period. (Quite a bit higher, actually, than the schizophrenia sample in the ECA, let alone the non-mentally-ill sample.)
In contrast, the ECA violence study used a truly representative sample of community residents in 3 US communities, with a combined sample size of about 10,000. The MacArthur study enrolled 519 community residents from patient-matched census tracts in Pittsburgh. And the subjects were enrolled from acute inpatient units and followed in the community after discharge. About 17% of the MacArthur study subjects had a primary diagnosis of schizophrenia, while 24% had a primary diagnosis of substance use disorder. The point is this: the MacArthur study was never designed as an epidemiological survey of the prevalence of violence in persons with and without mental disorder in the community. That’s just not what it was, thought it’s often cited as such. Rather, it was designed to study violence risk assessment for patients discharged from acute psychiatric facilities. (As long as we’re talking about representativeness. . .)
4. Regarding our use of terminology in the CATIE study, let’s just consider the primary, ordinary-language definition of “violence” in the dictionary: “exertion of physical force so as to injure or abuse” (MerriamWebster.com). That would include stabbing somebody or shoving them against the wall. And of course there’s a difference between these kinds of two acts; that’s why we coded one as “serious” and the other as “minor” violence in CATIE. But also consider that the Bureau of Justice Statistics defines battery as a violent crime. And battery is mainly what we’re talking about — that is, acts that would qualify as battery if reported to the police. So if you want to know about all violence, we think the threshold should be set there.
Here is another way of looking at it: “Choking” is one of the behaviors the MacArthur violence interview asks about. So imagine that Smith and Jones both attempt to choke their respective spouses. Same intent, same reason — the only difference is that Smith is a robust 35-year-old-man, and Jones is a 75-year-old-woman with arthritis; Mrs. Smith receives a visible bruise to the throat and requires medical attention, while Mr. Jones is uninjured and just needs a cough drop. Now, the MacArthur study would reserve the term “violence” for what Mr. Smith did, but would not apply it to what Mrs. Jones did. We, along with the dictionary and the Bureau of Justice Statistics, would use the term violent to describe both acts, when speaking in general terms, while making appropriate distinctions between them when speaking specifically about severity and consequence.
The distinction between serious violence and minor violence is important, but so is the distinction between absolute risk, relative risk, and attributable risk. You can use the same epidemiological data (our ECA study) to support any of the following three statements: (1) The large majority of people with mental illness do not commit violent acts; (2) People with mental illness are more than 3 times as likely to commit violent acts as people without mental illnes; (3) About 3 percent of the violent acts committed in the community are attributable to mental illess as a risk factor net other causes or risk factors (Swanson, 1994). (Which of these statements you choose to emphasize may depend on the rhetorical point you’re trying make.)
5. Speaking of rhetorical points, finally, let’s consider the statement that Grohol quotes from a Treatment Advocacy Center spokesperson: “The CATIE violence study found that patients with schizophrenia were 10 times more likely to engage in violent behavior than the general public (19.1% vs. 2% in the general population).” The TAC statement seems to imply that our CATIE study enrolled a comparison sample of the general public and compared them to schizophrenia patients in an epidemiological study. We did not do so. Taken out of context, then, the TAC statement could indeed be misleading.
— Jeff Swanson
Steadman HJ, Mulvey EP, Monahan J, Robbins PC, Appelbaum PS, Grisso T, Roth LH, Silver E. Violence by people discharged from acute psychiatric inpatient facilities and by others in the same neighborhoods. Arch Gen Psychiatry. 1998;55:393-401.
Swanson JW. Mental disorder, substance abuse, and community violence: an epidemiological approach. In: Monahan J, Steadman H, eds. Violence and Mental Disorder. Chicago, Ill: University of Chicago Press; 1994:101-136.
Swanson JW, Holzer CE, Ganju VK, Jono RT. Violence and psychiatric disorder in the community: evidence from the Epidemiologic Catchment Area surveys. Hosp Community Psychiatry. 1990;41:761-770.
Swanson, JW, Swartz MS, Van Dorn RA, Elbogen EB, Wagner HR, Rosenheck RA, Stroup TS, McEvoy JP, & Lieberman JA. A National Study of Violent Behavior in Persons With Schizophrenia. Arch Gen Psychiatry, 2006;63:490-499.
Thank you Jeff Swanson.
I think you just proved why it is always good to get both sides of an argument from the sides themselves.
what cause the teen have violence in relationship?
Great reply Jeff. I’m glad I took the time to read it. It just goes to show how easy it is to misread study data. In addition, one study is just that, one study. Of course there should be follow ups to determine the validity of your results.