No Benefit, Possible Harm From Routine Depression Screening

Fran Lowry

September 23, 2011

September 23, 2011 — Routine screening for depression in primary care, as recommended by organizations in the United States and Canada, has not been shown to be beneficial, and may even be harmful, according to new research published online September 19 in the Canadian Medical Association Journal. In addition, in this era of fiscal restraint, this screening is a waste of precious healthcare dollars, the authors write.

"Canadian and US task force recommendations suggest screening, and there are many places in Canada where there is screening going on, or healthcare bodies are putting in place provisions to screen patients for depression. Essentially they assume that it's a good thing, but there is no evidence that it is," lead author Brett D. Thombs, PhD, from McGill University, Montreal, Quebec, Canada, told Medscape Medical News.

"In fact," he added, "it's pretty clear when you do screening, whether you do cancer screening or any other kind of screening, that you are going to harm some people."

In Canada right now, more people are taking antidepressants than actually have depression, and the same is true for the United States, Dr. Thombs said.

"In Canada, 7% to 8% of adults over the age of 35 are on an antidepressant, whereas the estimated rate of depression in the population is 4%. In the United States, 15% of adults over 35 are on antidepressants, and this far exceeds the rate of depression in that country, so we're putting more people on medication than actually need it," he said.

In this analysis, Dr. Thombs and other experts "took a good hard look at the evidence" for screening recommendations in primary care settings in the United States, Canada, and the United Kingdom.

They came to the conclusion that although the prevalence of depression and the availability of relatively easy-to-use screening instruments make it "tempting" to endorse widespread screening, they could find no benefit in the practice.

Not Responsible Practice

They could find no trials that showed patients who underwent screening had better outcomes than those who did not when the same treatments were available to both groups.

Dr. Thombs said his research turned up only a single documented attempt to screen and provide care for depression in a clinical setting. In this study, 1687 patients at high risk for depression were invited to complete a questionnaire.

Of these patients, 780 returned the screening questionnaire, and of them, 226 (28.9%) showed positive for depression. Of patients who screened positive for depression, 173 patients were further assessed by a diagnostic interview, which detected 71 patients with major depression. Of these patients, 36 were already having their depression treated, and 18 did not attend their appointment or declined treatment.

Only 17 of the original 1687 patients (1.0%) eligible for screening started treatment for their depression.

"Put another way, about 100 people had to be invited to be screened for 1 person to receive treatment for depression," Dr. Thombs said.

"At this point, it's hard to understand how it would be responsible to screen patients for depression," he said. "Before we can start screening patients, we need some better randomized controlled trials that would find evidence of benefit."

In the meantime, physicians should educate their patients about depression.

"They should make sure patients are aware that depression can be a problem that affects their health in many ways, and let them know that this is something that a physician can work with them to improve. This is very different from mechanistically screening with a questionnaire and basing decisions on a point total."

Better to Screen Subgroups?

Commenting on this study for Medscape Medical News, Anton P. Porsteinsson, MD, William B. and Sheila Konar professor of psychiatry at the University of Rochester School of Medicine and Dentistry, New York, said he was concerned about the conclusion reached by the study's investigators.

"It is very well known that depression is associated with multiple negative outcomes. There is lower compliance with treatment, and depression may also be an early harbinger of dementia. So we should be looking for it," he said.

Still, he agreed that widespread, routine screening probably is not necessary.

For him, it would be better to look for depression in older individuals.

"Screening all comers may not make much sense. But this doesn't mean that there aren't some groups that should be looked at further. Other medical conditions are more common in older people, and screening and detection may help prevent worse outcomes in terms of their illness load and risk of death," he said.

"General screening of anyone who comes into a primary care practice might not be high yield enough, but in certain subgroups it may make sense to screen. The importance of early recognition and treatment in these groups may be higher."

Dr. Thombs and Dr. Porsteinsson have reported no relevant financial relationships.

CMAJ. Published online September 19, 2011.