Tired All the Time? It Might Not Be Depression

Symptoms That Could Point to Another Illness

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Sometimes symptoms that seem to point to depression can actually be pointing to something else entirely. Here, we look at illnesses that have similar symptoms to depression.

Illnesses that cause depression-like symptoms
Verywell / Nusha Ashjaee

Depression-Like Symptoms

Imagine that you have the following complaints:

  • You are tired all the time
  • You have no motivation for things you once enjoyed
  • You've had a change in your eating habits (either eating more or lost your appetite)
  • You lack energy
  • You are sleeping a lot (or you have trouble sleeping)
  • You are depressed or anxious

While these symptoms are often caused by depression, they could be caused by several other conditions. For example, thyroid problems and chronic fatigue syndrome can also result in these symptoms. It's even possible, although probably less likely, that you have fibromyalgia, sleep apnea, or an autoimmune disorder, such as rheumatoid arthritis or lupus.

Thyroid Problems

Thyroid problems can lead to either weight loss and feelings of anxiety, or weight gain and feelings of depression. They can also result in a complex mix of symptoms that don't seem to make sense. Other common symptoms of hypothyroidism include those that are also common in depression, such as difficulty concentrating, sluggishness, and fatigue. 

While they are separate conditions, depression can often be a symptom of hypothyroidism. The traditional model of thyroid function suggests that hypothyroid (underactive thyroid) results in depression and weight gain, while hyperthyroid (overactive thyroid) results in anxiety and weight loss.

Research suggests that nearly 70% of people who are diagnosed with hypothyroidism experience symptoms of depression.

The traditional treatment involves medications that bring your body chemistry under control. Symptoms of depression may get better or go away once the underlying thyroid condition has been treated appropriately with medication.

In order to determine what is going on, your doctor will use blood tests to confirm the presence of a thyroid condition. These tests look at the levels of thyroid hormones including thyroxine and thyroid-stimulating hormone (TSH).

However, standard blood tests may sometimes miss T3 and T4 hormone levels, which can also be indicators of thyroid functioning. If you are having symptoms of depression, talk to your doctor about the possibility of a thyroid condition.

Chronic Fatigue Syndrome

Chronic fatigue syndrome (CFS) is a condition that is characterized by severe fatigue that interferes with your everyday life, as well as several other symptoms such as memory problems, headaches, and muscle and joint aches. The underlying cause of chronic fatigue syndrome hasn't yet been discovered, and treatment may involve certain medications or alternative therapies.

Because chronic fatigue syndrome shares symptoms with other medical and psychiatric illnesses, it is not uncommon for it to be misdiagnosed as depression or some other condition. People may also experience both CSF and depression at the same time.

One important distinction between the two conditions is that while individuals with depression feel disinterested in doing the things they used to enjoy, those with chronic fatigue usually still have an interest in activities but lack the energy to do them.

Talk to your doctor if you have symptoms such as severe fatigue so that you can be evaluated to determine if it is CSF, depression or some other factor causing your exhaustion.


Fibromyalgia seems to overlap with chronic fatigue, but people with this disorder also have chronic pain all over their bodies. The disorder is usually diagnosed by tender points in certain muscles which respond with pain when touched a certain way. Sleep disturbance is common in chronic fatigue and fibromyalgia.

Research is ongoing into the causes of fibromyalgia and treatment often involves a multi-pronged approach.

Estimates suggest that 40% of people with fibromyalgia also have a co-occurring major depressive disorder.

Like depression, there is no specific test that can diagnose fibromyalgia. Instead, doctors must rely on an assessment of your health history and symptoms. While fibromyalgia shares some common symptoms with depression, diagnosis of the condition requires the presence of widespread pain and tenderness the body.

Treatment for fibromyalgia usually involves a combination of treatments, therapies, and lifestyle changes. Pain medications and antidepressants are often used to control some of the symptoms of this condition.

Autoimmune Disorders

Autoimmune disorders involve the immune system attacking the body. Rheumatoid arthritis and lupus are examples of autoimmune disorders. Autoimmune processes have also been implicated in diabetes and multiple sclerosis (MS). These disorders almost always involve a complex symptom picture, which can include depression. They aren't nearly as common as depression, but they can present with some similar symptoms.

One study found that autoimmune disorders may play a role in triggering the onset of depression. The study found that having an autoimmune disorder increased the risk of subsequent depression by 45%. 

Depression may be linked to autoimmune conditions for biological reasons, but dealing with chronic illness can also contribute to symptoms of depression. Research has found that depressive symptoms typically emerge over the course of an autoimmune condition and are associated with psychosocial factors, chronic pain, and long periods of disablement.

Sleep Disorders

Sleep disorders, such as obstructive sleep apnea, can also cause many symptoms similar to those of depression.

Sleep apnea is a type of sleep disorder that causes people to stop breathing in their sleep. It can make sleep difficult and lead to daytime fatigue. Past research has shown that sleep disturbances can have a serious impact on mood.

One study found that approximately 46% of people with sleep apnea have symptoms of depression.

If you snore or if you feel that your sleep is disturbed, speak with your doctor about the possibility of further testing. Your doctor will evaluate your health history and look for symptoms of sleep apnea or another sleep disorder. These symptoms may include snoring, excessive daytime tiredness, dry mouth, difficulty sleeping, and repeated nighttime waking.

A Word From Verywell

Depression remains the more common cause of most of these symptoms. It is important to remember that people can have more than one diagnosis at a time, too. There are certainly people who have both clinical depression and hypothyroidism, for example.

Some symptoms are more common in one disorder than the other and help in clarifying the diagnosis. People with hypothyroidism, for example, frequently gain weight. This can happen in depression, of course, but it is even more common with low thyroid. People with chronic fatigue can be depressed, but it is also common for them simply to be very tired and not the least bit sad.

Your best bet is to work with your health care provider in exploring your symptom picture. Lab tests can help make a definitive diagnosis in some cases.

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