07/11/2025
Mental illness is often difficult to diagnose.
At least 1/3 of people diagnosed with depression may have something else.
According to a 2012 article in Current Psychiatry, 26 to 45 percent of patients referred for âdepressionâ did not meet the diagnostic criteria for a depressive illness. A 2009 study discovered that general practitioners can only correctly identify depression in 47.3% of casesâand shockingly many doctors diagnose depression in people who actually donât have it.
Here are four conditions commonly mistaken for depression:
1. Bipolar disorder
Like depression, bipolar disorder involves periods of intense lows. During these lows, people with bipolar disorder experience the same symptoms found in depression. They may feel hopeless, worthless, or even suicidal. However, people with bipolar disorder also experience high periods, or mania, in which they feel confident, productive, or on top of the world. Sometimes this manic phase is so pleasant that people with the disorder are unable to recognize it as part of their illness, and so they only seek help during their low periods.
According to a study published in The British Journal of Psychiatry, up to 22 percent of people with bipolar disorder are mistakenly diagnosed with depression. Another study found that people with bipolar disorder experience an average gap of 10 years before they receive the proper diagnosis. But recognizing the difference between bipolar disorder and depression is vital because the medications used to treat depression can often worsen the symptoms of bipolar.
2. Hypothyroidism
In this condition, the thyroid gland does not release a sufficient amount of hormones. Because these hormones are necessary for the brain and body to function, people with this disorder typically experience fatigue, diminished concentration, and a low moodâall characteristics of depression.
3. Diabetes
People often develop Type 2 diabetes without recognizing it. They may suddenly find themselves losing weight, feeling fatigued, and growing irritable. Because all of these symptoms are also associated with depression, people may fail to recognize that their body is having problems with insulin. One precursor to Type 2 diabetes, insulin resistance, has been significantly linked to depression. Individuals with diabetes are also at risk for âdiabetes distress,â a condition that mimics depression. A 2014 study found that people diagnosed with both diabetes and depression experienced reduced depression symptoms after receiving interventions to help manage diabetes.
In other words, their symptoms were not due to depression, but the stress of living with a chronic illness. Because depression is measured with scales that are symptom-based and not tied to cause, in many cases these symptoms may actually reflect the distress that people are having about their diabetes, and not a clinical diagnosis of depression.
4. Chronic fatigue syndrome
Also known as myalgic encephalomyelitis or systemic exertion intolerance disease, this condition is characterized by extreme fatigue that has no apparent cause. Chronic fatigue syndrome also involves difficulty concentrating, muscle pain, and problems with sleepâall symptoms associated with depression as well, which is why people with chronic fatigue syndrome are so frequently misdiagnosed. A study published in The Primary Care Companion to the Journal of Clinical Psychiatry found that chronic fatigue syndrome is underdiagnosed in more than 80 percent of the people who have it, with depression being the most common misdiagnosis.
Depression is a very real and very serious illness that affects millions of people each year. The majority of individuals who are diagnosed with depression are diagnosed correctly and are able to recover with proper therapy and medication.
Still, a misdiagnosis is always possible. If you are being treated for depression but arenât feeling better, it is entirely possible that you have a disorder that mimics the condition.
