In about three weeks, Los Angeles County's mental health system will start self-destructing. Many county clinics will be closed, already overcrowded psychiatric emergency rooms will be deluged and up to 26,000 severely disturbed patients will be stranded, officials said.

But the crisis facing the county's most psychotic and suicidal citizens didn't start last week when massive mental-health cuts in the state's new budget prompted the county's mental health director to declare a "state of emergency."

The system started eroding in the 1970s, but for many it only became tangible last year. After blaming their problems on another year of meager state funding, county officials closed five of 28 clinics.

The consequences came swiftly.

During the last year, for instance, physicians at Martin Luther King Jr./Drew Medical Center have released hallucinating patients if they do not appear to be suicidal to free scarce beds, according to Dr. Anna Smith, vice chairwoman of the hospital's department of psychiatry, who compares the practice to "playing Russian roulette."

With psychiatric admissions up 43% since April, 1989, severely mentally ill patients sometimes sit two or three days in a waiting room before a bed is free.

What has happened since the summer of 1989, mental health activists warned, is only a precursor to what can be expected in the coming months. And, they said, it frightens them.

"It's hard to grapple with the enormity of the problem," said Ann Brand, president of the Assn. of Community Mental Health Agencies.

With no place else to turn, many disturbed people have ended up at County-USC Medical Center shackled to their beds with leather restraints. In recent months, 30 to 60 patients a day could be found tied to their beds, said many psychiatrists. They are sharing rooms with cancer patients, heart attack victims and others in the medical wards because the 116 beds in the locked psychiatric wards--where shackles are not needed--are filled.

Numerous psychiatrists, who asked not to be identified for fear of reprisal, told The Times similar stories:

Some County-USC patients have laid on urine-soaked sheets and waited three or four days to see one of the psychiatrists, who said they are overwhelmed with the crush of suicidal and psychotic people. Frightened or angry patients sometimes cut or bruise their limbs trying to escape from restraints. One man in his early 20s recently managed to free himself and was found standing on a 13th-floor ledge talking to God. He was rescued.