If you or a loved one feels sad or excessively tired or is having sleep problems, you may assume depression is to blame. But experts say many conditions mimic depression — and doctors can get it wrong.
In fact, about 26 to 45 percent of patients referred for “depression” do not meet the diagnostic criteria for the illness, according to an article in Current Psychiatry. One analysis of 118 studies found that general practitioners correctly identified depression in only 47 percent of cases, and that they often diagnose it in people who don’t have it.
The challenge for physicians is that there is no single, definitive test for depression, says psychiatrist Jonathan E. Alpert, M.D., chair of the Council on Research at the American Psychiatric Association.
“We can’t send someone for a blood test or an MRI to make the diagnosis of depression,” says Alpert, who is also chair of psychiatry and behavioral sciences at Montefiore Medical Center and the Albert Einstein College of Medicine.
Instead, to get a depression diagnosis, guidelines call for patients to have at least five of nine specific symptoms (see box) for more than two weeks. Health care providers should also rule out other conditions, Alpert says.
Experts say it’s especially important to consider other possible diagnoses in older adults. While it’s certainly true that people over 50 can experience depression, most people first experience the condition in early life. In addition, older adults are more likely to have atypical symptoms or other conditions that can cause depression or be mistaken for it.
“It’s often challenging to diagnose depression because the symptoms may overlap with chronic medical conditions, early dementia, hearing and vision loss, and medication side effects,” says Meredith Gillam, M.D., a geriatrician and medical director of the University of North Carolina Geriatrics Clinic in Chapel Hill. “It takes time and patience for family and clinicians to work through what is really going on.”
The biggest danger of a misdiagnosis is that you might have a serious condition — cancer or dementia, for example — that would benefit from early treatment.
Here are some of the most common conditions that can mimic or cause depression:
1. A thyroid disorder
Thyroid issues are a common disorder that can be mistaken for depression, says Joseph Lai, a general practitioner at Novant Health in Charlotte, North Carolina.
The thyroid is a butterfly-shaped gland that regulates important body functions, like your heart rate and energy level. The risk of a thyroid problem increases as you age.
“The thyroid is one of those little organs that has its fingers in everything,” Lai says. “If not working properly, it can definitely mimic depression.”
A thyroid problem can cause fatigue, feelings of sadness and irritability — all symptoms that overlap with depression.
However, weight gain or swelling, intolerance to cold and extreme fatigue can point to an underactive thyroid rather than depression, Alpert says. Someone who is depressed may feel unmotivated or uninterested in doing things, while someone with an underactive thyroid may feel like they just don’t have the energy, he says.
Overactive parathyroid glands, a different thyroid disorder that creates high calcium levels in the blood, can also cause depression-like symptoms.
About 20 million Americans have some form of thyroid disease, and as many as 60 percent don’t know it, according to the American Thyroid Association. If you suspect a thyroid problem, consider asking a health care professional to test for it.
