As we exited through the back alley of the theater, we saw her sitting on the ground, flanked by two garbage cans. Dan Aykroyd had just ended "The Twilight Zone" by asking John Lithgow (whose visions of a blue monster on the airplane wing had already landed him in a straitjacket): "Do you want to see something really scary?" I wondered briefly if this was what Aykroyd had in mind.

I recognized her as one of St. Elizabeths Hospital's rejects, a woman with the biochemical abormalities in her brain we call schizophrenia. She chatted easily with herself, seemingly unaware of the sudden influx of passers-by who had interrupted her scavenging efforts. Her dress was the latest in bag-lady fashion, bizarrely arranged and collected, and three Safeway bags ensured her full membership in the wandering sorority.

She is one of several hundred schizophrenics who roam the streets of Washington as bag ladies and grate gentlemen. Nobody knows their number because nobody has bothered to count. The total number of homeless persons living on the streets and in shelters in the nation's capital has been estimated at between 2,000 and 5,000. The percentage of these with schizophrenia is at least 25 percent, and a survey in Philadelphia found it to be 44 percent. New York City is estimated to have 36,000 homeless, and they are part of the urban moonscape in almost every American city--Atlanta, Detroit, Phoenix, Seattle, Columbus, New Haven, San Jose.

She had not, of course, always been a bag lady. She may have been, as were other schizophrenic bag ladies I have examined, formerly a housewife with three children, a head nurse on a hospital ward, or a college student. But that was before the disease began, the illogical thinking and delusions, auditory hallucinations and social withdrawal that are the hallmarks of the disease. That was also before her initial treatment by private psychiatrists who recommended intensive psychotherapy, now known to be useless for treating schizophrenia. And before her stays in the state hospitals and encounters with psychiatrists from other countries whose knowledge of psychiatry was only slightly better than their halting English. Eventually she just gave up, and her family gave up, and she wandered off to join the legion of the inner-city damned.

When she had been discharged from the state hospital she had not been as sick. She was in fact one of the lucky ones who was given an appointment at the local community mental health center for a follow-up visit. But she could not find the center, and when her anti-psychotic medicine was used up, her symptoms rapidly returned. The community mental health center dropped her from its roles when she failed to show up; no effort was made to locate her. Schizophrenic patients are not really welcome at the centers anyway, for they are not considered to be "good patients" (i.e., they are not verbal, cannot pay part of their fees). Less than 10 percent of all patients seen at such centers have schizophrenia despite the vaunted rhetoric that launched this movement in the brave Kennedy days of the early '60s.

She is eligible for Medicaid and food stamps, but her brain disease makes the normally confusing bureaucracy impossibly tortuous. And even if she had a Medicaid card, most private psychiatrists do not accept Medicaid patients. Private psychiatry is an elite profession for the worried well; in Washington only seven of the city's 1,100 psychiatrists have offices in the poorer Northeast or Southeast sections of the city where more than half of the population lives.

If sufficient research had been done, the biological causes of schizophrenia might now be known. But no lobby for such research has ever formed, and the National Institute of Mental Health has never given it priority. This research neglect stands in sharp contrast to the numbers: for each person with insulin- dependent diabetes there are three with schizophrenia; for each person with multiple sclerosis there are 20 with schizophrenia; for each person afflicted with muscular dystrophy there are 40 with schizophrenia. Yet the amount of research funds available for finding the causes of schizophrenia is exactly the same as that available for studying tooth decay.

She stands silently now, her back against the vacant building, looking into space. She is a 20th-century gargoyle, mute testimony to the failures of American psychiatry, federal plans and local social services. The index of our care for the disabled, for those who cannot care for themselves, is the true index of civilization.

Do you want to see something really scary? Take a walk down the alleys of the inner city, the real twilight zone.

The writer is a psychiatrist at St. Elizabeths Hospital.