Maggie Scheie is getting married in May.

So what? you may ask. So are lots of other bright, attractive young women.

Maggie Scheie, who is 32, has a degree in psychology and is working on her master's, at the same time holding down a full-time job.

Big deal, you say.

But for Maggie Scheie it is a very big deal. Because for the past decade or so, Maggie Scheie has had depression. It wasn't just that she was depressed. She was, of course, but that was only a part of it. Maggie Scheie had the illness called depression. Eventually it became manic-depression, the double-edged mood disorder that cycles between hopeless, unremitting, unending depression and a frenetic, buzzing, agitated high, then plummets again into the bleakest depths.

Scheie hospitalized herself on four occasions and, she said recently, "I was really convinced I was going to spend my life in a mental institution in some back ward, just completely forgotten."

"If we had it to do over," said Dr. Robert M.A. Hirschfeld, chief of the affective and anxiety disorders branch of the National Institute of Mental Health, "we would certainly call depression something else. I like to use the term 'clinical depression,' because the term 'depression,' per se, can refer to all different kinds of things. The carpenters think of it as something you eradicate with a plane. Economists think it is a very serious problem indeed.

"You use the term 'depression' and people say, 'Oh yeah, I know what that's like, that's the way I felt last week or when I had trouble with my job, my marriage, my life.'

"But that is not necessarily true."

Having depression is not having the blues.

However, there are enough things in common between depressive illness and having the blues that virtually everyone can identify with it to some extent.

And that makes depressive illness an especially good metaphor for mental illness in general, at least in the public mind, said Dr. Frederick K. Goodwin, director of scientific and intramural research at NIMH.

"One of the interesting things about depression is that it provides the easiest access for teaching people about psychiatric problems," he said, "and that is because the concept of depression is innately understandable to people because most people have had experiences that are somewhat . . .[like] the full depressive illness.

"Almost everybody knows what it is like to wake up in the middle of the night and not be able to go back to sleep because of an obsessive worry or preoccupation; most everybody knows what it feels like to lose your capacity for pleasure; most everybody knows what it feels like to have slowed thinking, to be unable to concentrate because of some depressing thought.

"What most of us don't know is what it is like to have those symptoms, relentlessly, week after week. Still, we know enough about it to be able to connect to it . . .

"So as a teaching tool, and a way to destigmatize mental illnes, education about depression is a very important way to decrease the sense of strangeness about psychiatric illness."

The basic difference, Goodwin said, between depression-the-blues and depression-the-illness "is the duration of the symptoms and how many are occurring at the same time." And of course the most distinguishing characteristic of depressive illness is the degree to which it impairs the normal functioning of its victim. Plenty of people can walk around, go to work, do pretty much what they need to do while they are, a la Pagliacci, crying on the inside. The truly clinically depressed person, likely as not, wouldn't have been able to get out of bed, much less function in the real world.

On the basis of a recent major survey conducted by the National Institute of Mental Health, it is now estimated that about 14 million Americans are suffering from a clinical depression.

The survey also disclosed that fewer than half of them are seeking professional help, even though treatments can help 80 percent of those with depression and manic-depression, at least temporarily.

Most studies indicate that twice as many women as men suffer from clinical depression, but manic-depressive illness strikes males and females equally. Nor are children immune from these disorders. It has been estimated that psychiatric disorders including depressions affect up to 12 percent of nonadults, from toddlers on up.

Depressive disorders cost this country about $20 billion a year.

Scheie's first episode of depressive illness occurred when she was a freshman at the University of Iowa. She had gone off to college full of promise and hope -- on three scholarships, fulfilling the hopes of her family and of herself. She dropped out after her freshman year.

"When I came home I was in a severe state of depression and anxiety, and my family was at a complete loss. I felt very isolated, unable to communicate. I felt I had let them down incredibly and I had this tremendous guilt.

"But I couldn't talk to them. I felt like my brain wasn't functioning. I had a hard time just carrying on a conversation. The depression," she said, "was really scary, because I felt that some incredible, horrible thing had happened to me, but there were no signs on the outside. I couldn't explain to people that inside I was completely different. I felt estranged, bizarre, weird. My thoughts were much slower. It was terrifying to be in college and sit through a whole lecture and be unable to remember a word of what the professor had said. Or I'd sit down to read the textbook and I couldn't absorb any of it.

"It felt like some bizarre trick of fate, that something terribly wrong had happened to me on the inside, but nobody would ever understand."

In just a few sentences, Maggie Scheie had listed several of the specific symptoms mental health workers use to distinguish and diagnose major depressive illness. Her mood was one of abject misery, and it lasted for months. Her feelings of guilt and self-blame are typical. Her slowed thinking is considered a key symptom in major depression, as was her inability to function -- in her case, as a student.

According to the third edition of the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM-III), the diagnostic bible of virtually all mental health professionals, four of eight common symptoms of major depression -- in addition to subjective feelings of gloom -- must be present for at least two weeks for a diagnosis of major depression to be made. These include:

*Eating too much or too little.

*Sleeping too much or too little.

*Too much restlessness or too much lethargy.

*Loss of interest or pleasure in usual activites, including decrease in sex drive.

*Overwhelming fatigue.

Feelings of worthlessness and self-reproach. Inappropriate guilt.

*Feelings of diminished ability to think or concentrate.

*Recurrent thoughts of death or suicide, or actual suicide attempts.

Depressive illness has been, and still is, called various things -- starting with melancholia, which means "black bile," one of the "humors" the Greeks believed controlled emotions. Black bile, the Greeks believed, caused depression.

There is also affective (mood) disorder, manic-depressive illness, illnesses that are unipolar (recurrent depression alone) or bipolar (depression alternating with mania). Then there is endogenous depression (coming from within, with possible genetic bases), exogenous or neurotic or psychotic depression (associated with life events or environmental factors), not to mention dysthymia, a milder kind of chronic, ongoing blue funk, and cyclothymia, a milder cousin to manic-depression. Seasonal affective disorder (SAD) appears to be a subtype of manic-depressive illness, with its subjects reflecting many of the symptoms of clincial depression during the winter and kicking into hypomanias (mild manic episodes) during the summer.

Never mind.

As Goodwin put it, there was a period in the world of psychiatry when things got "over-dichotomized."

And now, for the most part, psychiatrists and psychiatric researchers are beginning to see depressive illness on a spectrum, distinguishing distinct subtypes, but also distinguishing between clinical depressions -- those which require professional help -- and a host of personality characteristics once classified as "neuroses."

"Depression is a syndrome," Hirschfeld said, "a collection of diseases and disorders with different etiologies [causes] and sometimes different treatments."

Goodwin, who has been involved in the treatment of and research on clinical depressions for the past two decades, sees three distinct recent "revolutions" in the characterization and treatment of these disorders.

Before the development of drugs that affected mood and emotions, therapists did not need to know very much about the details of a patient's symptoms, whether or not the episodes of depression or depression and manias were recurrent, whether or not there was a family history of depression. This was the heyday of the "talk therapies."

"The primary goal of a therapist was to get to know the individual patient," Goodwin said. "And the fact that he had a depression was almost secondary to what kind of life he led, the kind of family he had, the kind of person he was."

Then, with the explosion of research on the brain, and the development of psychoactive drugs, it all changed. Anti-depressant drugs be- came available; lithium worked extraordinarily well on manias.

"It is," Goodwin said, "perhaps the best example of the way in which the unanticipated development of a practical treatment forces a conceptual refocusing of a whole field." Suddenly, he said, "it forced people mental health professionals to think more carefully about distinguishing among subtypes of depression, because for the first time it made a difference in what you did."

The clear success of drug therapies was followed by a period of "rethinking fundamental assumptions," in which, he said, "it was predictable that there would be an acceptance by some that certain patients who were more severely ill and more functionally disabled could, in fact, respond to these medications when they were not responding to psychotherapy.

"So we went from a diagnostic scheme that was based on emphasis on individual characteristics and life events to a scheme that was initially over-dichotomized, in which we had 'reactive' and 'endogenous' depressions, 'reactive' versus 'endogenous,' or 'neurotic' versus 'psychotic.'

"This," said Goodwin, "was a transitional phase in which psychiatry was, in effect, saying: 'Well, we've got this group of people who really have a biological illness, and it is endogenous and treatable by drugs. Moreover, it involves biological and genetic factors. Then on the other side we have everybody else, with a disorder which is simply a reaction to life events and treatable exclusively by psychological efforts.' "

Now, Goodwin believes, psychiatry is "moving into the third phase, which is more realistic and, in effect, there is a rapprochement, in which we now have a recognition of the spectrum of depression and a recognition that the biological underpinnings extend to some degree through a broader range of depressive syndromes than was originally thought. And at the same time, the psychosocial factors are important across a broader range than we thought."

Indeed, Goodwin said, the newest research indicates that a combination of psychotherapy and drugs seems to be the most effective treatment for many depressions. "Basically, the studies have shown that the more physiological, functional aspects of the depression sleeping and eating disorders, gastrointestinal upsets, for instance respond only to the medications, so that a person on an antidepressant drug begins to sleep better, eat better and so forth, whereas the self-esteem, interpersonal relationship aspect of the depression responds primarily to psychosocial intervention talk therapy .

"People getting psychosocial intervention alone," he said, "can be shown to improve in self-esteem and interpersonal relations, but they'll still wake up in the middle of the night," manifesting the biological symptoms.

There are some still newer studies from a group at the University of California in Los Angeles demonstrating that bipolar, or manic depressive, patients on a treatment program combining lithium with a "particularly focused" kind of psychotherapy had, Goodwin said, "an eightfold improvement in outcome at a six-month follow-up compared to those who had lithium alone."

Emil Kraepelin, the German psychiatrist who identified manic-depressive illness as a separate entity back in the 1920s, believed the illness was inherited. There is considerable evidence tending to support that hypothesis -- for instance, the clustering of mood disorders in families of patients with depressive or manic-depressive illness, especially in those with the most serious symptoms.

Basic genetic research, much of it conducted under Goodwin's aegis at NIMH, has been devoted to finding a genetic marker in depressive or manic-depressive illness. There have been tantalizing hints, but so far no breakthrough.

Nevertheless, the new breed of psychiatrist, mostly trained in the past decade or so, is finding that certain people are more vulnerable than others to having a life event -- a major disappointment or a major loss -- kick into a genuine, major depression. But once this happens, especially in bipolar illness, the recurrences, the cycles seem to take on a life of their own, with manias and depressions alternating in some cases as often as every 48 hours. Suicide is a genuine risk in this patient population -- or it was, until the advent of lithium.

Manic-depression accounts for less than a quarter of major depressive illnesses, but it is by far the most serious.

Maggie Scheie started having manic episodes about six years after her depression started. She was fortunate in that she had sought help early, but, she recalled, although she was put on one drug or another, "in spite of all the things I took -- well, they might have helped some -- I never felt really good. I would get better or worse, but never really good.

"I was kind of glad about the manic episode, because in the first place, it was a lot more fun not to be depressed. I started having energy for the first time in years, feeling like I could accomplish something. But then it got extreme. I felt like I knew everything, and I was very impatient with people who couldn't see things the way I saw them."

By then, Scheie was sleeping about 45 minutes a night, going on buying sprees, living on junk food. As the manic cycle began to wind down, she began to have thoughts of suicide -- but, she said, "I was afraid to take action because I thought that maybe there was a hell and it would be worse than this."

People at the height of a manic episode feel as though they have endless energy, boundless creativity and are certainly all-knowing and probably all-powerful. They can often hallucinate, and somehow those parts of the brain -- or chemicals in the brain -- that normally inhibit behavioral excess are simply not working. Typically, these people indulge in bouts of reckless driving or might invest a life's savings in hopelessly foolish schemes.

Sometimes, when the manias are less severe, people can indeed be highly creative. Composers Georg Frideric Handel and Gustov Mahler were known for their flip-flopping moods, for example, and are often cited as manic-depressives. However, Dr. Norman Rosenthal, a staff psychiatrist at NIMH who has used full-spectrum lights to successfully treat SAD -- seasonal affective disorder -- notes that Handel did virtually all of his composing during the summer months. So did Mahler, and both may have been suffering from the milder seasonal disorder that cycles with the length of the days.

With the discovery that lithium could prevent the manic-depressive cycling, and a finding that in some vulnerable patients anti-depressant drugs could set off a manic episode, there came yet another revolution for the psyciatric community, according to Goodwin.

Researchers discovered the "recurrent nature of affective disorders."

The phenomenon was noticed first in Europe, where populations tend to stay in one place. But in mobile America, it wasn't until the advent of psychoactive drugs and the attendant need to study psychiatric histories that it became clear that major depressions as well as manic-depression were recurrent illnesses.

"My basic point," said Goodwin, "was that the discovery of an effective prophylactic treatment has put clinicians into the position of needing to think about recurrence, needing to count episodes, needing to estimate cycling. They are not delivering good care if all they are doing is treating the episode and saying to the patient, 'Come back if you get sick again.' "

Goodwin estimates that perhaps as many as 80 percent of all major depressive illnesses will recur sometime in a patient's lifetime, a larger figure than most specialists will venture, but based on Goodwin's own review of world literature.

The answers to the causes of these disorders are still elusive, but most of even the most recalcitrant depressions and manias will respond to treatments already at hand, including electroconvulsive therapy for some unremitting or suicidal depressions and an antiseizure drug called carbamazepine for those manic-depressives who do not respond to or cannot tolerate lithium.

Maggie Scheie's psychiatrist put her on lithium as soon as her manic phases came on. From then on, she said, "I found I was able to maintain a lot more stability, to feel a lot more like myself."

Scheie now works for the National Alliance for the Mentally Ill, a support group for mental patients, former mental patients and their families. Her therapy has been officially ended, and she is eager to help others who may be experiencing the same things she went through.

"In the beginning," she said, "it is hard to accept that nobody can wave a wand and make things get better. So even when you agree to accept help, and then you find the help doesn't necessarily have the answers, that's real hard.

"But even just to have somebody to see once a week, somebody who is there to give you hope and support, that is enormously important . . . One thing I would say, no matter how dark it seems, time does change things. And even if it looks hopeless now, the darker the winter, the brighter the spring. That may sound like a cliche, but it was really true for me."