The lifetime risk of suicide among persons diagnosed with schizophrenia is
about half of the rate routinely quoted in the psychiatric literature,
according to a meta-analysis of 61 studies.
Rather than the conventional estimate that 10 percent of those with
schizophrenia will die by suicide, the new study estimates that 5.6 percent
will commit suicide during their lifetime, with most deaths occurring shortly
after the onset of illness, said Brian A. Palmer, M.D., M.S., M.P.H., V. Shane
Pankratz, Ph.D., and John Michael Bostwick, M.D., of the Mayo Medical School
in Rochester, Minn. The results remained the same regardless of whether newer
(DSM-III or later) or older diagnostic criteria were applied.
The previous estimate was based on the number of suicides listed as the
cause of death among the total number of people with schizophrenia who died
during the course of follow-up, reported the researchers in the March
Archives of General Psychiatry. That simply gave the proportionate
mortality—the percentage of dead people who had schizophrenia and died
by suicide. Such an approach works only when all subjects are observed until
they die—a practical impossibility—or if suicides as a proportion
of all deaths occur at the same rate over time, which they do not. Most
suicides among persons with schizophrenia occur in the first few years
"Proportionate mortality provides information only about the
dead," they said. "The direct use of proportionate mortality
rates... assumes a constant rate of suicide over a lifetime and will therefore
overestimate suicide risk."
Using the proportionate mortality method among new-onset cases resulted in
a suicide rate of 30.6 percent, a "dramatic" overweighting of
lifetime risk. A more meaningful number would be the case fatality rate, the
percentage of the total sample who killed themselves, according to the
They initially estimated a suicide rate of 4.9 percent. However, after
factoring in the length of the studies included in the meta-analysis, they
concluded that 5.6 percent of persons with schizophrenia will commit suicide
at some point following diagnosis, explained Pankratz, the statistician among
the authors. "This number is a better reflection of the true percentage
of schizophrenics who will suicide, as it accounts for differences in the
length of the various studies."
While using a statistical sword to cut the expected suicide rate in half
may seem like an important accomplishment, a 5 percent rate still represents a
major risk, said Carol A. Tamminga, M.D., a professor of psychiatry at Texas
Southwestern Medical Center in Dallas. She added that epidemiological studies
like this deserve attention.
"These new methodologies are needed because the use of suicide rates
was not truly scientific before," she said. "Sometimes people used
the 10-percent figure to simply underscore the importance of the
Palmer, Pankratz, and Bostwick reviewed the medical literature using online
databases (MEDLINE and PsychInfo) and hand searching bibliographies. Out of
632 relevant papers, they found 32 studies of 25,578 patients with
schizophrenia who were enrolled at various times in the course of their
illness and 29 studies of 22,598 patients who were identified at either
illness onset or at first hospital admission.
"First-admission and new-onset studies more accurately estimate
suicide risk because they include the initial years of the illness when death
by suicide is most likely," they said.
While welcoming the meta-analysis, Tamminga would like to see further
research examining the effects of variables other than age, including gender,
comorbidities, medication use, and care setting.
For instance, she said, it would be helpful to see whether the use of
second-generation antipsychotic drugs were associated with lower suicide
rates, or whether there were differences between patients in hospital and
those in community care, where more lethal means of suicide were available, or
why more people without a diagnosis of schizophrenia who commit suicide are
depressed but incidence of depression is lower among people with
"People with schizophrenia who commit suicide are not necessarily
depressed but see themselves in a psychosocial situation that seems hopeless
to them," said Tamminga. "Clinicians must help them find meaning
and purpose in their lives rather than demoralization."
Since suicide is concentrated in the early course of schizophrenia, wrote
Palmer, Pankratz, and Bostwick, "intervention and prevention efforts are
therefore best directed toward [patients in] the early stages of the
"The Lifetime Risk of Suicide in Schizophrenia" is
posted online at<http://archpsyc.ama-assn.org/cgi/content/full/62/3/247>.▪
Arch Gen Psychiatry200562247