October 13, 2011 — Patients with any major psychiatric disorder are at significant risk for suicide after their first hospital visit, according to new research.
In a Danish registry study of more than 175,000 individuals who were followed-up for up to 36 years, investigators found that among men, those with bipolar disorder or unipolar affective disorder had the highest absolute risk for suicide. Schizophrenia, followed closely by bipolar disorder, represented the highest risks for women.
Comorbidities were also significant risk factors for both sexes, and the cooccurrence of deliberate self-harm increased the risk by 2-fold.
"The steepest increase in suicide incidence occurs during the first years after first contact," write lead author Merete Nordentoft, MD, from the Psychiatric Center Copenhagen and Copenhagen University in Denmark, and colleagues.
The investigators note that the absolute risk for suicide varied between 2% and 8% for the different psychiatric disorders studied.
"Our estimates are lower than those most often cited, but they are still substantial and indicate the continuous need for prevention of suicide among people with mental disorders," the authors write.
The study appears in the October issue of the Archives of General Psychiatry.
The researchers report that a frequently cited study published in 1977 by Charles P. Miles, MD, and colleagues estimated that among individuals with unipolar affective disorder, alcoholism, and schizophrenia, suicide rates would be 15%, 15%, and 10%, respectively.
However, that review "was based on rather small studies with selected samples and a rather short follow-up, and several authors later concluded that, for different reasons, Miles' estimates were most likely too high," write the investigators, noting that several recent studies have found much smaller estimates.
For the current study, investigators evaluated data on 176,347 people from the Danish Civil Registration System who were born between 1955 and 1991 and had their first contact with a mental health professional after the age of 15 years. All participants were followed-up until death, emigration, or the end of 2006, for a maximum of 36 years.
In addition, 5 healthy control patients from the registry with no diagnosis of psychiatric illness were matched for each participant.
The registry was linked with the Danish Registers of Causes of Death to glean suicide information, as well as with the Danish Psychiatric Central Register.
The participants were separated into subgroups based on classifications from the International Statistical Classification of Diseases, 8th or 10th Revision: schizophrenia, schizophrenia psychoses, bipolar affective disorder, unipolar affective disorder, substance abuse, and anorectic disorder.
They were also examined for comorbidities and for whether or not they participated in deliberate self-harming actions.
Results showed that the absolute risk for suicide was highest for bipolar disorder (7.77%), unipolar affective disorder (6.67%), and schizophrenia (6.55%) for the men.
Among the women, schizophrenia (4.91%), bipolar disorder (4.78%), and schizophrenia-like disorders (4.07%) were the highest risk factors.
Comorbid unipolar affective disorder significantly increased the risk for suicide for all diagnostic groups, as did comorbid substance abuse, except for the men with schizophrenia.
The cooccurrence of deliberate self-harm across all the groups doubled the risk for suicide, and the most at-risk of all the groups were men with bipolar disorder who also deliberately self-harmed themselves (17.08%).
In the nonpsychiatric/healthy controls, the risk for suicide was 0.72% for men and 0.26% for women.
"[I]t is beyond doubt that the risk of suicide is high in all the investigated mental disorders, and suicide preventive measures should be a mandatory part of treatment programs," write the investigators.
"The fact that the steepest increase in suicide risk occurs during the initial years after first contact with mental health services can serve as an argument for intensive early-intervention services," they add.
Direct Measure of Risk
"This is a really important study because there's been a lot of debate and a lot of numbers thrown out in terms of what percent of people with psychiatric disorders go on to die by suicide," Eric D. Caine, MD, chair of the Department of Psychiatry at the University of Rochester Medical Center, New York, and codirector of the Center for the Study and Prevention of Suicide, told Medscape Medical News.
"We know that it's a lot higher than the general population, but the numbers that have been out there are really radically different. So this is important because it gives a real direct measure of something that was asserted a few years back," he said.
Noting that the national registry used "is really quite incredible," Dr. Caine said that the data are important to the world at large because they are so complete.
"If we assume that the general clusters of psychiatric disorders diagnosed there are roughly comparable, then the information that comes out of Denmark can be very, very valuable. And even though it's really focused here on the psychiatric population, it teaches us about the burden of suicide across much of the life course," he noted.
Some of the concerns he voiced included that "some people were only tracked a few years and others were tracked since the 1950s," that the investigators used changing diagnostic systems, and that 3 definitions of self-harm were used over the course of the study.
Dr. Caine noted that although rates of suicide were less than what other researchers have estimated in the past, they were still quite substantial.
"I think this study really teaches us that all those prior results were in the right direction, but we're now seeing much more clearly what the proper magnitude is, and what the burden of suicide is."
"You can also clearly see that the suicide risk continues to climb over years. Certainly there's a steep climb in the first year after hospitalization, but it continues to climb. So, this isn't something you think about just the first day or week or month. This is something you think about for years," he concluded.
The study was supported in part by the Stanley Medical Research Institute. The study authors and Dr. Caine have disclosed no relevant financial relationships.
Arch Gen Psychiatry. 2011;68:1058-1064. Abstract
Authors and Disclosures
is a freelance writer for Medscape.
Deborah Brauser has disclosed no relevant financial relationships.