Bipolar Disorder, Substance Abuse Disorder
Linked To Greater Suicide Risk

 

Veterans with bipolar disorder (BD) are at a significantly increased risk for suicide compared with their counterparts with other mental health conditions, new research suggests.

Although all psychiatric diagnoses examined (including schizophrenia, substance use disorders, depression, posttraumatic stress disorder [PTSD], and other anxiety disorders) showed elevated suicide risks, BD was associated with the highest risk for the overall patient population, report investigators.

In fact, 9% of the veterans who committed suicide had been diagnosed as having this disorder. In addition, BD was the highest suicide risk factor for the subgroup of male-only veterans.

"Our findings that [BD] is a risk factor is pretty consistent with the literature, but there really hasn't been any way in the past to see how it might compare to other psychiatric conditions," principal investigator Mark A. Ilgen, PhD, from the Ann Arbor Veterans Affairs Healthcare System and the Department of Psychiatry at the University of Michigan, told Medscape Medical News.

"I was actually surprised that in this sample, [BD] came out a stronger predictor than the other disorders, particularly schizophrenia," added Dr. Ilgen. "This makes it particularly appropriate for targeted intervention efforts."

Substance use disorder was found to be the highest risk factor for the subgroup of female-only veterans, followed closely by BD.

Dr. Ilgen said that, overall, he would recommend carefully monitoring symptoms and conducting a comprehensive suicide assessment in patients with any psychiatric disorder. "Even in our lowest risk conditions, people with those conditions were almost twice as likely to die by suicide as those without."

The study is published in the November issue of the Archives of General Psychiatry.

Suicide Research "Difficult"

Although suicide is "1 of the most common causes of preventable mortality" in the United States, the crude rate of suicide in this country is only about 23 per 100,000 men and 6 per 100,000 women, the researchers note.

However, past autopsy studies estimate that 90% to 98% of those who die by suicide have at least 1 psychiatric disorder.

"This study is part of a number of projects we've undertaken to look at the risk factors for suicide in veterans, but it's very difficult because suicide is a rare event," said Dr. Ilgen.

"Even though as a psychologist I've learned a set of indicators considered high risk in most patients, the research basis for that is still emerging. It's just not as well established as, say, research on the risk factors for heart disease.

"So for this study, we wanted to look at a set of psychiatric conditions and how each contributed to risk of suicide — and how they compared with one another," he added.

The researchers examined computerized records of patients who received any treatment from the Department of Veterans Affairs (VA) during fiscal year (FY) 1999 (n = 3,291,891).

They also examined data from the Centers for Disease Control and Prevention's National Death Index. All patients were alive at the start of FY 2000.

"Psychiatric diagnoses were obtained from patient treatment records in FY 1998 and 1999 and used to predict subsequent death by suicide during the following 7 years in sex-stratified survival analyses controlling for age," report the investigators.

High Risk for All Conditions

Results showed that 25.6% of the veterans had at least 1 type of psychiatric diagnosis. This included 26.5% of men and 17.3% of women.

Depression was the most common diagnosis overall (14.5%) and in the male-only (14.7%) and female-only subgroups (12.7%).

This was followed by substance use disorders at 10% overall (10.7% of men, 3.2% of women). BD was the least common diagnosis (2.9% of the overall population, of men, and of women).

There were 7684 overall deaths by suicide during the 7 years of follow-up (7426 men, 258 women). Of these, 46.8% had at least 1 psychiatric condition.

Noting that that figure is less than the over 90% typically found in autopsy studies for those who die by suicide, the study authors write that this was probably due to stigma, especially among men with military experience, which may have kept patients from reporting their mental health symptoms to physicians.

"This probably means that VA treatment providers are not picking up on the psychiatric condition in a lot of individuals," added Dr. Ilgen. "I think this speaks to the importance of screening, to be on the look-out for signs of psychiatric problems.

"Among individual psychiatric conditions, [BD] had the strongest association with suicide, with the lower limit of its 95% CI [confidence interval] being greater than the upper limit of the 95% CI associated with any other psychiatric conditions," write the investigators.

Overall, the next highest risks for suicide came from a diagnosis of depression, followed by substance use disorders, schizophrenia, other anxiety disorders, and PTSD. This was the same order of risk for the men-only subgroup.

For the women, the highest risk was for those with substance use disorders, followed by BD, schizophrenia, depression, PTSD, and other anxiety disorders.

Table. Association Between Psychiatric Conditions and Risk for Suicide

Psychiatric Condition	HR (95% CI) for All Patients	HR (95% CI) for Men Only	HR (95% CI) for Women Only
Any psychiatric diagnosis	2.60 (2.47 – 2.74)	2.50 (2.38 – 2.64)	5.18 (4.08 – 6.58)
Substance use disorders	2.47 (2.30 – 2.64)	2.27 (2.11 – 2.45)	6.62 (4.72 – 9.29)
Bipolar disorder	3.19 (2.94 – 3.46)	2.98 (2.73 – 3.25)	6.33 (4.69 – 8.54)
Depression	2.70 (2.56 – 2.85)	2.61 (2.47 – 2.75)	5.20 (4.01 – 6.75)
Other anxiety	2.21 (2.05 – 2.39)	2.10 (1.94 – 2.28)	3.48 (2.52 – 4.81)
PTSD	1.93 (1.79 – 2.08)	1.84 (1.70 – 1.98)	3.50 (2.51 – 4.86)
Schizophrenia	2.33 (2.15 – 2.52)	2.10 (1.93 – 2.28)	6.08 (4.35 – 8.48)

CI = confidence interval, HR = hazard ratio, PTSD = posttraumatic stress disorder

"Because of the lower number of women than men who use [VA health] services and the lower rate of suicide among women, the CIs were wider," explain the investigators.

They note that their overall results differ from a recent study that found similar rates of suicide in those with depression, schizophrenia, and BD. However, that study focused on diagnoses during psychiatric inpatient stays, which "would identify individuals with a more severe presentation of the disorder.

These findings highlight the importance of improved identification, diagnosis, and treatment of psychiatric diagnoses...of all health care system users.

"It is possible that risk of suicide in those with more severe depression...more closely resembles the risk associated with more severe bipolar disorder," they add.

However, because those who use VA services tend to be in poorer general physical and mental health compared with the general US population, the study authors urge caution in generalizing these results to nonveterans.

"When you think about suicide risk in the general population, you're often trying to draw a conclusion from very specific subgroups and trying to figure out how they relate to the overall US, and it's tough to do," said Dr. Ilgen.

Nonetheless, "these findings highlight the importance of improved identification, diagnosis, and treatment of psychiatric diagnoses...of all health care system users," the investigators write.

Continued Monitoring Vital

"I've worked for the VA for about 20 years, and I have to say that I'm very proud that it has the type of computerized healthcare system that allows this type of work to be done," Keith A. Young, PhD, vice chair of research in the Department of Psychiatry at Texas A&M Health Science Center in Temple and core leader for Neuroimaging and Genetics at the VA Center of Excellence for Research on Returning War Veterans in Waco, Texas, told Medscape Medical News.

"It's really only one of the very few places in the world where you could have done a study like this. Suicide is a relatively rare event and therefore kind of difficult to study. So having a great computerized system has really been a boon to this kind of research," said Dr. Young, who was not involved with this study.

I don't believe there's any indication that it's just in veterans that [BD] has a high suicide risk. The veteran population was chosen as a sample of convenience, having a record on different psychiatric diagnoses and on suicide.

However, "this particular study didn't really find anything that surprising as we all suspected that people with [BD] have a high risk of committing suicide," he said. "But I do want to add that in no way was this study indicating anything special about veterans. I don't believe there's any indication that it's just in veterans that [BD] has a high suicide risk. The veteran population was chosen as a sample of convenience, having a record on different psychiatric diagnoses and on suicide."

Dr. Young also said he wasn't sure he agreed with the investigators that there was "a markedly increased rate" of suicide in BD over the other disorders.

"There's a slight increase over schizophrenia and depression. But clinically, it's not very significant. I'm hoping that this paper doesn't get interpreted as a reason to really focus on [BD] at the risk of not paying attention to other psychiatric illnesses. The high risk comes with all those other disorders and was almost as high for some of them," he said.

"What I did find interesting, and it was surprising, was that PTSD was one of the least likely conditions to be associated with suicide. It almost goes against what we see in the clinic and I'm not sure how to explain that finding. Although it was still an increased risk factor, it was not up there with the leaders."

When asked if the reason some veterans didn't get diagnosed as having a mental health disorder was because they were not comfortable providing this information, Dr. Young said that may have been "particularly true" in the early stages of this study.

"I would say that we've done a better job in the last 5 years of getting veterans to come out with their mental health needs. You can see this in the increase of newer veterans coming to the VA for mental health care. And I think that if we were to redo this study in the next 10 years, I think we'd find that we're going to be doing an even better job of catching these folks," he said.

Overall, "this study gives us even more data on how important it is to monitor our psychiatric patients for suicide risk and that would include those treated for substance abuse and drug use. We can treat to prevent suicide with both drugs and other treatments. This is a reversible condition," concluded Dr. Young.

This study was funded by the Veterans Affairs Office of Mental Health Services, Patient Care Services, and the Health Services Research and Development Service Merit Review Entry Program Award. The study authors and Dr. Young have disclosed no relevant financial relationships.

Arch Gen Psychiatry. 2010;67:1152-1158.

Journalist

Deborah Brauser is a freelance writer for Medscape. She has disclosed no relevant financial relationships.

-From Medscape Medical News: “Bipolar Disorder Linked to Greater Suicide Risk vs Other Mental Disorders”, by Deborah Brauser, November 3, 2010, http://www.medscape.com/viewarticle/731870 retrieved 11/8/10.

 

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