[spiritual_emergency]

Elsewhere in the blogosphere, I recently became involved in a discussion where the issue of suicide and schizophrenia was raised and a rate of 10% was introduced as fact. I'd always questioned that number as based on the following...

Quote

Schizophrenia is reported to occur in approximately 1% of the population. America has roughly 300,000,000 people. If the stated rate of 1% is correct we should anticipate 3,000,000 of those people carry a diagnosis of schizophrenia. If 9-13% were killing themselves and we rounded that number off to that aforementioned 10%, we should anticipate that 300,000 schizophrenic Americans will kill themselves.

In 2005, the number of Americans who committed suicide was 32,637 (*). The data provided doesn't tell us how many of them were schizophrenic but it seems reasonable to conclude the percentage of "schizophrenics" would not have been 100%.

(* This figure is similar to previous years.)

One of the problems with statements such as "10% of people with schizophrenia commit suicide" is that it doesn't tell us the time frame during which that rate was determined. For example, if 10% of "schizophrenics" committed suicide on one specific day (i.e. Columbus Day), that would be a very different piece of information as opposed to something like the rate of risk over a lifetime.

I went searching for some more refined answers and came across the following two studies that are worthy of sharing...

Quote

...From each of about 60 studies information was collected on number of patients, deaths, suicides, and length of follow up.

Results
Twenty-nine cohorts observed schizophrenics from date of admission or illness onset, and another 32 were composed of any type of patient. The studies were as small as a few tens of patients, to over 9,000. Most involved several hundred patients, followed up for two to 22 years.

For those studies that examined patients from first admission or new onset (22,598 patients), the case fatality estimate (percentage of original sample who died by suicide) was 2.9% (95% CI 4.3 to 5.6%). Of all deaths, 31% were deaths by suicide. Among studies using mixed samples (25,578 patients), the case fatality estimate was 2.3% (1.5 to 3.5%) and 6% of all deaths was by suicide.

Analysis according to time of follow up suggested that suicide risk was greater sooner rather than later after diagnosis or onset. The estimate of lifetime suicide prevalence in those observed from first admission or illness onset was 5.6% (95% confidence interval, 3.7% to 8.5%). Mixed samples showed a rate of 1.8% (95%CI, 1.4% to 2.3%). Case fatality rates showed no significant differences when studies of patients diagnosed with the use of newer criteria were compared with studies of patients diagnosed under older criteria. ...

About 1 in 20 schizophrenics will commit suicide during their lifetimes, more often near illness onset. The findings of the meta-analysis do seem to be borne out by other studies published since the meta-analysis was completed. For instance, there were 78 completed suicides in 4237 acute inpatients with schizophrenia admitted between 1985 and 2000 in Taiwan [3]. That is a rate of 2%, and half of the suicides occurred within four years of first admission, but Taiwan may well have lower rates of some important risk factors, particularly drug misuse. Rates of suicide in mainland China [4] in the late 1990s averaged 0.7% of the schizophrenic population annually (28,737 suicides in people with schizophrenia out of 4.25 million people with schizophrenia in China). If half of the suicides were in the first few years, that would equate to a lifetime risk of almost 6%. These two large studies in east Asia confirm the overall estimate of between 2% and 5% lifetime risk of death by suicide.

Source: Schizophrenia and Suicide

Quote

Schizophrenia's Suicide Risk May Be Less Than Thought
Aaron Levin

A new meta-analysis estimates that 5.6 percent of people with schizophrenia will commit suicide—half the rate usually reported in the psychiatric literature.

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...

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 following diagnosis.

"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 researchers. ...

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 issue."

Source: Psychiatric News April 15, 2005

[ScaredSad]

Very interesting. Thanks for sharing. I have only known one individual with schizophrenia who chose suicide so I don't really have enough experience to speak one way or other but it's interesting to read.