If you are being treated for depression but still aren’t feeling like yourself, you might have one of these often-misdiagnosed illnesses.

Misdiagnosed Health Depressed Woman Blue Abstract Illustration 

Every year, thousands of moms walk out of their doctor’s office with a prescription for an antidepressant. And there’s a good reason for that: Clinical depression is one of the most common mental disorders in the United States—and it can hit new mothers particularly hard, as exhaustion, hormonal shifts, and a major sense of “What happened to my old life?” takes hold. But women who feel this way aren’t always clinically depressed—often there is something else going on.

“Doctors tend to jump to the depression diagnosis first,” says Michelle Riba, M.D., professor of psychiatry at the University of Michigan in Ann Arbor. “However, if you look in any medical textbook, you’ll see pages of conditions that can masquerade as a mood disorder.” Landing on an accurate diagnosis is the key to getting better.

It took decades for Amanda Cullinan, a mom from Summerfield, North Carolina, to figure out why she had felt sad and anxious for almost as long as she could remember. Even in elementary school, she felt sensitive around other people. After starting a family, she was often so overwhelmed that she’d spend the entire day in bed after she got her kids off to school. Although Cullinan was always making to-do lists, she rarely checked off any tasks. Two doctors diagnosed her with depression and prescribed meds that “took the edge off” but failed to fix her problems.

Finally, three years ago, Cullinan had a breakthrough—courtesy of her son. “My 9-year-old was diagnosed with ADHD (attention deficit hyperactivity disorder), and as soon as he started taking medication for it, he had a complete turnaround. I thought, ‘His symptoms are similar to mine—could his problem be genetic?'” After going through a series of tests, Cullinan was herself diagnosed with ADHD, putting decades of suffering into perspective. “I started to cry, because everything finally made sense,” Cullinan says. She began taking a prescription stimulant the next day, and her life changed. “The anxiety and depression are gone. I can focus on my kids without getting frazzled and depressed,” she says.

Get to know five conditions that can be mistaken for depression, starting with the one that stumped Amanda Cullinan and her doctors.

1. ADHD

When you hear the acronym ADHD, the first image that pops to mind is probably an energetic little boy who can’t sit still. But ADHD is not confined to childhood: A study in The American Journal of Psychiatry estimates that about one in every 20 Americans ages 18 to 44 has the condition. “Adult women with ADHD aren’t usually hyperactive,” says Edward Hallowell, M.D., coauthor of Delivered From Distraction. “Their mind wanders, and they can’t pay attention long enough to complete a task.” That lack of focus and follow-through can lead to an overriding sense of shame that they can’t get anything done, and that shame can cause depression, Dr. Hallowell adds.

Women who experienced mild, undiagnosed ADHD symptoms during childhood sometimes find that the many stresses and demands of motherhood kick the condition into overdrive. The most common and clinically-proven prescription stimulants are Vyvanse and Adderall, which release chemicals that calm you down and improve focus and mood, Dr. Hallowell explains. Cognitive behavioral therapy and stress management can also help women gain control over their symptoms.

2. Hypothyroidism

A common cause of depressive symptoms in women can be traced to a little butterfly-shaped gland in the neck that produces hormones affecting every organ in the body. “The thyroid is like the gas pedal for the body, including the brain,” explains endocrinologist Antonio Bianco, M.D., Ph.D., professor of internal medicine at Rush University Medical Center, in Chicago. If the thyroid produces too much hormone (called hyperthyroidism), it can make you jumpy and anxious. But if it produces too little (known as hypothyroidism), everything in your body slows down, making you tired, unable to concentrate, and, yes, depressed. One in eight women will develop a thyroid disorder in her life, and up to 60 percent are unaware of their condition.

The most common cause of underactive thyroid is Hashimoto’s disease, in which the immune system attacks the gland, preventing it from making hormones. Postpartum thyroiditis, a condition similar to Hashimoto’s, strikes up to 10 percent of women after pregnancy. “If you have low energy and are feeling depressed at your postpartum checkup, ask your doctor to give you a simple blood test to check thyroid levels,” recommends Dr. Bianco. In most women, the condition goes away on its own within a year to 18 months, but for some moms it can become a life-long problem. Hypothyroidism can be managed by taking a synthetic hormone (levothyroxine) to replace the one your thyroid has stopped making.

3. Fibromyalgia and 4. Chronic Fatigue Syndrome

Long considered one of the hallmarks of depression, insomnia is also one of the telltale symptoms of these two disorders. “If you lie awake all night and also suffer from brain fog, pain, and exhaustion, there’s a good chance you have chronic fatigue syndrome (CFS) or fibromyalgia,” says Jacob Teitelbaum, M.D., author of The Fatigue and Fibromyalgia Solution. “One of the big differences is that with depression, you lose interest in activities you used to love. With CFS or fibromyalgia, you still wish that you could do them, but you’re just too tired.”

While no one is certain about the causes of these conditions, physical and emotional stresses may play a role. Dr. Teitelbaum says that any number of untreated infections (including Epstein-Barr and oral herpes) or hormonal problems could also trigger them. As many as 2.5 million Americans suffer from chronic fatigue syndrome, yet many health-care providers mistake it for a mental-health issue or consider it a figment of the patient’s imagination, according to a report from the Institute of Medicine. Fibromyalgia is similar to CFS, with the added “bonus” of widespread muscle pain.

Treatments for the two conditions include antidepressants, sleep meds, pain relievers, and lifestyle changes such as moderate exercise (though it can be a tall order for someone who’s perpetually exhausted).

5. Lyme Disease

This potentially debilitating illness is spread by ticks carrying the bacterium Borrelia burgdorferi. The CDC estimates that 300,000 people in the U.S. are diagnosed per year, but Lyme experts say that because blood tests can be unreliable and symptoms may go unnoticed, the number of infections may exceed 1 million. It can manifest as an entire textbook of neuropsychiatric symptoms, including brain fog, confusion, obsessive-compulsive disorder, psychosis, panic, and severe depression. “Lyme is known as ‘The Great Imitator,’ because it mimics so many other conditions,” says Richard Horowitz, M.D., author of How Can I Get Better? An Action Plan for Treating Resistant Lyme & Chronic Disease.

The Lyme infection releases inflammatory molecules called cytokines that travel to the brain, making circuits go haywire. “It’s like a fire inside the body,” Dr. Horowitz says. If not correctly diagnosed, a patient may be told she’s imagining her symptoms, which can send her into a deep depression. When Lyme is caught early (say, as soon as you spot a tick bite or its bull’s-eye rash) and is treated with antibiotics, it can be cured roughly 75 percent of the time. But some patients’ symptoms can linger for months or years. This is known as post-treatment Lyme disease syndrome. The hallmarks are good days and bad days when the symptoms—muscle and joint pain, tingly sensations that migrate throughout the body—change in intensity. Says Dr. Horowitz, “They may get worse around a woman’s menstrual cycle or get better or worse if she’s on antibiotics.”