Risk factors for violence and death are not restricted to schizophrenia

By Laura Cowen, medwireNews Reporter

Drug-use disorders, criminality and self-harm increase the risk for violent crime and premature death not only in patients with schizophrenia, but also in their unaffected siblings, researchers report.

“Therefore, a combination of population-based and targeted strategies might be necessary to reduce the substantial rates of adverse outcomes in patients with schizophrenia and related disorders”, suggest Seena Fazel (University of Oxford, UK) and colleagues in The Lancet Psychiatry.

The 38-year study included 24,297 Swedish people with schizophrenia and related disorders, 26,357 of their unaffected siblings, and 485,940 controls from the general population who were matched to the patients by age and gender.

Within 5 years of first diagnosis, 10.7% of men with schizophrenia and related disorders were convicted of a violent offence, 2.3% died from suicide and 3.3% died prematurely (before the age of 56 years). The corresponding figures for women were 2.7%, 1.5% and 2.0%.

Compared with the general population, men with schizophrenia were 6.6 times more likely to commit a violent crime, 18.3 times more likely to commit suicide and 8.1 times more likely to die prematurely, while female patients were 14.9, 31.1 and 8.1 times more likely to have each of these adverse outcomes, respectively.

Eric Elbogen and Sally Johnson, from the University of North Carolina-Chapel Hill School of Medicine, USA, highlight these findings in an accompanying comment. They point out that there was “a substantially stronger link between schizophrenia and suicide than between schizophrenia and violence”, even though “news coverage of schizophrenia and other psychiatric disorders often focuses on violence and crime.”

They add: “This study is perhaps the first to directly report data showing that in people with schizophrenia and related disorders, self-directed violence is a greater problem than is violence directed towards others.”

Drug use disorders, a history of violent crime and self-harm typically increased the risk of all three adverse outcomes for patients with schizophrenia and their unaffected siblings, compared with the general population. The hazard ratios for these events ranged from 1.3 to 7.2 and were generally higher in the siblings than in the patients.

However, the researchers point out that many other risk factors, such as relationship status and family income, were not shared across the different outcomes but were specific to individual outcomes in men or women. This suggests that “risk assessment and management might have to be carefully tailored for specific outcomes”, Fazel and co-authors remark.

The team also observed that the rate of violence and suicide increased more rapidly over the study period in the patients with schizophrenia than in their unaffected siblings, when compared with the general population. At the same time, the number of inpatient nights per year decreased and this decrease appeared to be associated with increased violence, but not with suicide or premature death.

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