Lana Barhum, freelance writer, has lived with rheumatoid arthritis and fibromyalgia since 2008. She uses her experiences to share expert advice on living successfully with chronic illness.

Anxiety is characterized by feelings of worry, nervousness, and unease, typically about an imminent threat or uncertain outcome. Like other emotions, anxiety is experienced in varying degrees. Moderate anxiety is typically a normal and even healthy reaction to stressful events. However, intense anxiety can become unhealthy and difficult to manage. While everyone experiences some degree of anxiety now and then, the symptoms and their intensity vary from person to person.

An anxiety disorder is different from everyday anxiety. “Anxiety disorder” is a general term applied to several different mental conditions that cause chronic fear, apprehension, nervousness, and worry. Anxiety disorders disrupt how people feel and behave and present physical symptoms too.

Defining anxiety

Kaplan & Sadock's Comprehensive Textbook of Psychiatry describes normal anxiety as a "diffuse, unpleasant, vague sense of apprehension, often accompanied by autonomic symptoms such as headache, perspiration, palpitations, tightness in the chest, mild stomach discomfort, and restlessness, indicated by an inability to sit or stand still for long."

In addition to the psychological symptoms mentioned above, anxiety may cause poor concentration, irritability, and sleep issues. Additional physical symptoms may include tremors and muscle tension. With severe anxiety, hyperventilation (over-breathing) may give rise to chest discomfort, dizziness, faintness, and numbness and tingling in hands and feet.

Some anxiety can be beneficial

Normal anxiety isn’t necessarily an enemy to be avoided. Often, anxiety kicks in just when you need it. You may find yourself anxious before making an important decision or when faced with a problem at work, for example. Moderate anxiety can help you cope with such difficult situations. Anxious feelings increase adrenaline in your bloodstream, boosting your strength and energy. You may also feel more alert.

A study reported in the British Journal of Psychology finds people with good memories who become anxious do better taking tests. The leader researcher, Dr. Matthew Owens, said, "The findings . . . suggest that there are times when a little bit of anxiety can actually motivate you to succeed.”

Other researchers believe worry and intelligence go hand in hand. One study, published in the journal Frontiers in Evolutionary Neuroscience, finds that “while excessive worry is generally seen as a negative trait and high intelligence as a positive one, worry may cause our species to avoid dangerous situations, regardless of how remote a possibility they may be. In essence, worry may make people ‘take no chances,’ and such people may have higher survival rates. Thus, like intelligence, worry may confer a benefit upon the species,” explained by Dr. Jeremy Coplan, the study’s author.

When is anxiety a problem?

Normal anxiety is sporadic and expected based on stressful circumstances. Harmful anxiety, conversely, is chronic, unfounded, and interferes with daily life, causing work, home, and social difficulties.

Events such as meeting your significant other's parents for the first time or facing a big exam that is worth half your grade may understandably bring on anxiety, but it goes away once the event has passed. Where normal, healthy anxiety can temporarily sharpen you physically and mentally, harmful anxiety impairs functioning and causes well-being to suffer.

Harmful anxiety can eventually become an anxiety disorder, where the anxiety doesn’t go away and gets worse over time. People with anxiety disorders are almost always anxious. Their fears are unreasonable. Even though the anxious person knows this, they struggle to control it. As the disorder worsens, the American Psychiatric Association says it may cause significant social or occupational difficulties.

Talk to your doctor

If you believe your anxiety is keeping you from enjoying life, don’t put off talking to your doctor. Anxiety disorders are treatable. In fact, some experts say they are the most treatable of all emotional disorders. Treatment typically involves medication, talk therapy, or both.

Also, it can help to know that you are not alone: anxiety is the most common of all mental disorders in the United States. The National Alliance on Mental Illness reports that an estimated 40 million American adults, or 18 percent of the population, have an anxiety disorder. With proper diagnosis and treatment, most people manage anxiety disorders and live healthy and fulfilling lives.

What helps you cope with anxiety? Together we can help one another in the community. Take a moment to comment below and share your advice.