Say no to depression.

Possibly the saddest fact about depression is that most of the suffering is unnecessary. Many people simply do not seek treatment, although even those with severe forms can be helped by medication and talk therapies that ease the pain and alter moods.

One reason treatment may be avoided is that many people consider mental illness to be different from physical illness. In a poll by the National Institute of Mental Health, nearly half of all respondents viewed depression as a "personal weakness" rather than the health problem it is.

All of us have bad days and even bad weeks. Do mild forms of depression need to be treated at all? The answer is yes--if usual sources of pleasure lose their meaning, and sadness or despair pervade one's life for weeks on end, says John Rush, M.D., director of the Mental Health Research Center at the University of Texas in Dallas.

Not just the blahs. Clinical depression should not be confused with the everyday "blahs" that most people encounter at one time or another. How can anyone tell the difference between the blahs, which are often overcome by getting more exercise or spending more time with friends and family, and depression serious enough to warrant professional help?

"They have the same basis and similar symptoms," says Douglas Jacobs, M.D., psychiatrist at Harvard Medical School, who has devised national screening programs. "But they differ in severity and usually last much longer."

Depression is "whole body" illness, affecting the way you eat and sleep, how you feel about yourself, and the way you look at life. It's not the same as a passing blue mood. "People with depressive illness cannot `pull themselves together' and get better," explains Jacobs.

Rule out physical illness. Researchers don't know exactly what causes depression. They do know that a single cause is unlikely. Rather, depression seems to stem from many psychological and biological roots.

The first step is a complete examination to rule out physical illness. Some drugs, including contraceptives and sleeping pills, are often contributing factors. A medical history will include questions about whether other family members have been treated for depression.

Treatment choice will depend on the outcome of the evaluation. Some people do well with talk therapy, and some with antidepressants. Others benefit from combined treatment: medication to gain quick symptomatic relief and psychotherapy to learn more effective ways to deal with life's problems.

Even when successfully treated, depression recurs at some later time in half of all patients. But fast intervention--within four weeks of onset--with combined therapy shortens the length of a second episode dramatically, says David Kupfer, M.D., psychiatrist at the University of Pittsburgh School of Medicine.

Kupfer believes that many people don't seek treatment because they think depression will fade. "The truth is that once someone has two depressive episodes, there's almost a 90 percent chance it will return," he says.

But no form of treatment should go on for too long if the patient is not improving, says Kupfer. "If medication or psychotherapy has not resulted in marked improvement in three months, then either the treatment or the therapist has to be changed."

Drugs not the only answer. "Depression is clearly responsive to a lot of drugs," says Dr. John Nemiah, M.D., psychiatrist at Dartmouth Medical School and editor of the American Journal of Psychiatry. "But that doesn't mean it's not important to sit down and talk with patients and see what their depression is all about."

Talk therapy, whether individual or in a group, is most useful with people whose personalities and life experience are the main causes of their illness. And it can range from informal counseling to the more structured approaches of cognitive or interpersonal therapy.

Antidepressants and lithium are most often used to treat depression. Of these, Prozac (fluoxetine hydrachloride) has become the drug of choice among doctors who are not psychiatrists--and who treat half of all clinically depressed people.

Peter Kramer, M.D., psychiatrist at Brown University and the author of Listening to Prozac (Viking, 1993), admits that for some patients Prozac goes beyond treating depression and alters personality traits. The problem is whether it will become the approved feel-good drug. Prozac seems "to give social confidence to the habitually timid, to make the sensitive brash, to lend the introvert the social skills of a salesman," worries Kramer.

Antidepressants appear to work by prolonging the message-relaying ability of neurotransmitters involved in mood swings--serotonin and norepinephrine. But there are several nondrug approaches to pry you loose from an unwanted blue mood. Next time you get the blahs, try one of these antidotes:

* Exercise. Of all the mood-altering self-help techniques, exercise seems to be the most efficient cure for a bad mood.

* Socialize. People with depression feel lonely and isolated. Balance those feelings by staying connected to other people.

* Think positive. People are often depressed when their thought patterns are negative and distorted.

* Be kind. Examine how you feel, think, and speak about yourself. If you're too critical, the result may be low self-esteem and deep depression.

* Mood foods. Scientists have reported a basic link between food and mood. "Carbohydrates stimulate the brain's production of serotonin, responsible for making us feel calm and relaxed," explains Harvey Ross, M.D., psychiatrist and author of The Mood Control Diet (Prentice Hall, 1990).

* Dream. Sleep can lift a blue mood by relieving exhaustion and allowing us to benefit from one of the oldest forms of mental therapy--dreaming. Treating sleep disturbances may also prevent depression, as insomnia is often an early symptom. Get help. If none of these six work, join a support group or get professional counseling.

Norman Brown is a freelance writer from Providence, Rhode Island, who writes on many topics, including business, health, and fitness.