A common perception of someone suffering from depression is a person who's sad and/or crying. Although you certainly may feel this way if you're depressed, the illness may also present itself in more subtle ways that you might not expect.

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Depression is a very common illness, with about 16 million adults in the U.S. having at least one major episode of depression in the past year. Despite there being many different types of treatment available, about two-thirds of people with major depression never seek treatment.

Sometimes they think they'll "snap out of it" on their own or they may be too embarrassed to address the condition. But delaying treatment could have devastating effects in every area of your life, and at its worst, could result in suicide.

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The following five signs are solid indicators that it could be time to talk to your doctor about depression.

Your mind seems foggy

If you have trouble concentrating or making decisions on an almost-daily basis, Health's website says, this could be a sign of depression. It can cause fuzzy, unfocused thinking that can affect your memory and ability to make good decisions. This could make you forget work deadlines as well as tasks you need to complete at home. At its most extreme, it could even lead you to engage in unhealthy, risky behavior.

You tend to get angry

Although most people probably associate depression with sadness, it can also cause you to feel irritated or angry over things that you would normally shrug off. If you find yourself raging at little things at work and home, you may actually be depressed. This can be especially true of men, Reader's Digest says, who may find it more socially acceptable to express anger rather than sadness when they go through something such as divorce.

You have unexplained pain

The Mayo Clinic says that unexplained pain such as back pain or headaches can sometimes be the first or only sign of depression. In fact, pain and depression can create a vicious cycle. If your depression is causing pain, this can make you further depressed, which increases your pain. In addition, depression-related pain that continues over time can create additional problems such as stress, low self-esteem and difficulty sleeping. Some forms of treatment can help with both pain and depression, while others treat only one condition, so you and your doctor can talk about what's best in your particular case.

Your eating habits have changed

Depression can affect many aspects of your life, including your eating habits. Health says you may experience a loss of appetite as well as a decreased interest in food and cooking. It can also have the opposite effect, making you more likely to try to soothe yourself by binge eating on unhealthy food. In addition, if you normally eat a healthy diet, but find yourself suddenly turning to junk food, you may want to talk to your doctor about depression.

You sleep too much -- or too little

Crawling into bed and escaping into sleep is behavior that may be associated with depression, according to Health. You may find yourself wanting to stay in bed and also escaping into naps when you can during the day. Depression can also cause you to stay awake late at night as you toss, turn and worry. And like many symptoms of depression, sleeping too much or too little can create a vicious cycle. You can feel tired and sluggish from too much sleep, so you may feel even worse, which can make you likely to sleep more or have more trouble getting to sleep at night.

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Getting help

The National Alliance of Mental Illness (NAMI) recommends the following tips for getting help:

  • Call 911, go to your local emergency room, or call the National Suicide Prevention Lifeline at 1-800-273-8255 if you're feeling suicidal.
  • If you think your condition is mild to moderate, make an appointment with your primary care physician.
  • If you think your condition is moderate to severe, make an appointment with a specialized doctor such as a psychiatrist.
  • Seek out community support groups, which can serve as valuable tools for help and to know you're not alone in suffering from depression. NAMI can help you find support in your area.