What is depression?

Just like a rash or heart disease, depression can take many forms. Definitions of depression and the therapies designed to ease this disease's grip continue to evolve. These shifts will continue to percolate through the field as more research flows in.

This special report addresses three main categories of depression:

major depression

dysthymia (a lasting, low-level depression)

bipolar disorder, previously called manic-depressive illness.

These terms don't begin to describe the tremendous variation in people's experiences of depression. Still, while the labels sometimes seem overly simple, they do help clinicians and researchers study depression and exchange information about its various forms. The categories have many overlapping characteristics, but each has its own distinguishing features.

What is major depression?

Major depression may make you feel as though work, school, relationships, and other aspects of your life have been derailed or put on hold indefinitely. You feel constantly sad or burdened, or you lose interest in all activities, even those you previously enjoyed. This holds true nearly all day, on most days, and lasts at least two weeks. During this time, you also experience at least four of the following signs of depression:

a change in appetite that sometimes leads to weight loss or gain

insomnia or (less often) oversleeping

a slowdown in talking and performing tasks or, conversely, restlessness and an inability to sit still

loss of energy or feeling tired much of the time

problems concentrating or making decisions

feelings of worthlessness or excessive, inappropriate guilt

thoughts of death or suicide, or suicide plans or attempts.

Other signs can include a loss of sexual desire, pessimistic or hopeless feelings, and physical symptoms such as headaches, unexplained aches and pains, or digestive problems. Depression and anxiety often occur simultaneously, so you may also feel worried or distressed more often than you used to.

Although these symptoms are hallmarks of depression, if you talk to any two depressed people about their experiences, you might well think they were describing entirely different illnesses. For example, one might not be able to summon the energy to leave the house, while the other might feel agitated and restless. One might feel deeply sad and break into tears easily. The other might snap irritably at the least provocation. One might pick at food, while the other might munch constantly. On a subtler level, two people might both report feeling sad, but the quality of their moods could differ substantially in depth and darkness. Also, symptoms may gather over a period of days, weeks, or months.

Despite such wide variations, depression does have certain common patterns. For example, women are almost twice as likely as men to suffer from depression. And while major depression may start at any time in life, the initial episode occurs, on average, during the mid-20s.

Depression or hopelessness may feel so paralyzing that you find it hard to seek help. Even worse, you may believe that treatment could never overcome the juggernaut bearing down.

Yet nothing could be further from the truth. The vast majority of people who receive proper treatment rebound emotionally within two to six weeks and then take pleasure in life once again. When major depression goes untreated, though, suffering can last for months.

Furthermore, episodes of depression frequently recur. About half of those who sink into an episode of major depression will have at least one more episode later in life. Some researchers think that diagnosing depression early and treating it successfully can help forestall such recurrences. They suspect that the more episodes of depression you've had, the more likely you are to have future episodes, because depression may cause enduring changes in brain circuits and chemicals that affect mood (see "The problem of recurrence"). In addition, people who suffer from recurrent major depression have a higher risk of developing bipolar disorder than people who experience a single episode.

What is dysthymia?

Mental health professionals use the term dysthymia (dis-THIGH-me-ah) to refer to a low-level drone of depression that lasts for at least two years in adults or one year in children and teens. While not as crippling as major depression, its persistent hold can keep you from feeling good and can intrude upon your work, school, and social life. If you were to equate depression with the color black, dysthymia might be likened to a dim gray. Unlike major depression, in which relatively short episodes may be separated by considerable spans of time, dysthymia lasts for an average of at least five years.

If you suffer from dysthymia, more often than not you feel depressed during most of the day. You may carry out daily responsibilities, but much of the zest is gone from your life. Your depressed mood doesn't lift for more than two months at a time, and you also have at least two of the following symptoms:

overeating or loss of appetite

insomnia or sleeping too much

tiredness or lack of energy

low self-esteem

trouble concentrating or making decisions

hopelessness.

Sometimes an episode of major depression occurs on top of dysthymia; this is known as double depression.

Dysthymia often begins in childhood, the teen years, or early adulthood. Being drawn into this low-level depression appears to make major depression more likely. In fact, up to 75% of people who are diagnosed with dysthymia will have an episode of major depression within five years.

It's difficult to escape the grasp of untreated dysthymia. Only about 10% of people spontaneously emerge from it in a given year. Some appear to get beyond it for as long as two months, only to spiral downward again. However, proper treatment eases dysthymia and other depressive disorders in about four out of five people.

What is bipolar disorder?

Bipolar disorder always includes one or more episodes of mania, characterized by high mood, grandiose thoughts, and erratic behavior. It also often includes episodes of depression. During a typical manic episode, you would feel terrifically elated, expansive, or irritated over the course of a week or longer. You would also experience at least three of the following symptoms:

grandiose ideas or pumped-up self-esteem

far less need for sleep than normal

an urgent desire to talk

racing thoughts and distractibility

increased activity that may be directed to accomplishing a goal or expressed as agitation

a pleasure-seeking urge that might get funneled into sexual sprees, overspending, or a variety of schemes, often with disastrous consequences.

Between episodes, you might feel completely normal for months or even years. Or you might experience faster mood swings (known as rapid cycling). Bipolar disorder actually takes many forms. For example, symptoms of depression and mania may be mixed during cycles. Or you might not have full-blown mania; instead, you could have a milder version known as hypomania.

Is pain a symptom of depression or a cause?

Pain is depressing, and depression causes and intensifies pain. People with chronic pain have three times the average risk of developing psychiatric symptoms — usually mood or anxiety disorders — and depressed patients have three times the average risk of developing chronic pain. When low energy, insomnia, and hopelessness resulting from depression or anxiety perpetuate and aggravate physical pain, it can be impossible to tell which came first or where one leaves off and the other begins.

Pain slows recovery from depression, and depression makes pain more difficult to treat. For example, depression may cause patients to drop out of pain rehabilitation programs. So it often makes sense to treat both pain and depression; that way they are more likely to recede together.

Brain pathways

Normally, the brain diverts signals of physical discomfort so that we can concentrate on the external world. When this shutoff mechanism is impaired, physical sensations like pain are more likely to become the center of attention. Brain pathways that handle pain signals use some of the same chemical messengers (neurotransmitters) that are involved in the regulation of mood. (See "Nerve cell communication" for more information.)

When these pathways start to malfunction, pain is intensified, along with sadness, hopelessness, and anxiety. And as chronic pain, like chronic depression, takes root in the nervous system, the problem perpetuates itself. The mysterious disorder known as fibromyalgia may be an example of this kind of biological process linking pain and depression. Its symptoms include widespread muscle pain and tenderness at certain pressure points, with no evidence of tissue damage. Brain scans of people with fibromyalgia show highly active pain centers, and the disorder is more closely associated with depression than most other medical conditions. This leads some experts to speculate that the pain sensitivity and emotional storminess of fibromyalgia result from faulty brain pathways.

Treating pain and depression in combination

In pain rehabilitation centers, specialists treat both problems together, often with the same techniques, including progressive muscle relaxation, hypnosis, and meditation. Physicians prescribe standard pain medications — acetaminophen, aspirin, ibuprofen, and other nonsteroidal anti-inflammatory drugs (NSAIDs), and in severe cases, opiates — along with a variety of psychiatric drugs. Almost every drug used in psychiatry can serve as a pain medication (see "Medications used for depression and bipolar disorder"). By relieving anxiety, fatigue, or insomnia, these medications also ease any related pain. In addition, antidepressants — sometimes given in low doses — may relieve pain in ways unrelated to their antidepressant effects.

Exercise and psychotherapy are commonly used at pain centers, too. Physical therapists help patients perform exercises not only to break the vicious cycle of pain and immobility, but also to help relieve depression. Cognitive and behavioral therapies teach pain patients how to avoid fearful anticipation, banish discouraging thoughts, and adjust everyday routines to ward off physical and emotional suffering. Psychotherapy helps demoralized patients and their families tell their stories and describe the experience of pain in its relation to other problems in their lives.

Bipolar disorder usually starts in early adulthood. It's equally common among women and men, although certain variations of it strike one sex more than the other. Hypomania, for example, occurs more often in women. Women are also more likely to experience major depression as their first episode and to have more depressive episodes over all. Men, on the other hand, typically experience manic episodes first and tend to have more of them than depressive cycles.

Bipolar disorder is a recurring illness. Nine out of 10 people who have a single manic episode can expect to have repeat experiences. Suicide rates in people who have bipolar disorder are higher than average. Successful treatment, however, can cut down on the number and intensity of episodes and reduce suicide risk.

What are your symptoms?

Identifying your symptoms can be a useful first step toward gaining a deeper understanding of how depression, dysthymia, or bipolar disorder affects you. It may help you open a discussion with a doctor or therapist, too.

Be aware, however, that self-tests like this one cannot diagnose depression or any other mental illness. Even if they could, it's easy to dismiss or overlook symptoms in yourself. It may help to have a friend or relative go over this checklist with you. Also, remember that your feelings count far more than the number of check marks you make. If you think you are depressed or if you have other concerns or questions after taking this test, talk with your doctor or therapist.

Depression checklist

Start by checking off any symptoms of depression that you have had for two weeks or longer, or that you've noticed in the family member or friend you're concerned about. Focus on symptoms that have been present almost every day for most of the day. Then look at the key below. (The exception is the item regarding thoughts of suicide or suicide attempts. A check mark warrants an immediate call to a doctor.)

I feel sad or irritable.

I have lost interest in activities I used to enjoy.

I'm eating much less than I usually do and have lost weight, or I'm eating much more than I usually do and have gained weight.

I am sleeping much less or more than I usually do.

I have no energy or feel tired much of the time.

I feel anxious and can't seem to sit still.

I feel guilty or worthless.

I have trouble concentrating or find it hard to make decisions.

I have recurring thoughts about death or suicide, I have a suicide plan, or I have tried to commit suicide.

Manic episode checklist

Check off any symptoms you've noticed for a week or longer in yourself or the person you're concerned about. Focus on symptoms that are present almost every day during most of the day.

I feel extremely elated, uninhibited, or irritable.

I have ideas or plans that will have a big impact on myself or on others.

I have a continuous stream of thoughts racing through my brain.

I am sleeping far less than I normally do.

I am talking far more than I normally do.

I feel quite distracted and find it hard to focus.

I am energetically pursuing my goals, or I feel agitated and unable to sit still.

I am actively pursuing pleasures that may have negative consequences, such as buying whatever I want or entering into sexual liaisons or business schemes.

Scoring the test

Depression and dysthymia. If you checked a total of five or more statements on the depression checklist, including at least one of the first two statements, you (or your loved one) may be suffering from an episode of major depression. If you checked fewer statements, including at least one of the first two statements, you may be suffering from a milder form of depression or dysthymia.

Manic episode. Checking off four statements on the manic episode checklist, including the first statement, suggests possible bipolar disorder. Note that hypomanic symptoms (milder manic symptoms) may last for as little as four days, not a full week or longer.

Review Date: 2008-04-01

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