Doctors at St. Elizabeths Hospital, who have been evaluating the mental condition of John W. Hinckley Jr., have concluded that he suffers from a severe, chronic mental disorder and remains a danger to himself as well as to others, particularly to actress Jodie Foster, informed sources said yesterday.

Sources said the doctors determined that symptoms of Hinckley's illness include a "pattern of fixed, grandiose, homicidal and suicidal ideas" that Hinckley holds for Foster. Hinckley's delusions about Foster are now the "organizing and guiding influence in his life," sources said the doctors found.

Hinckley has been confined at St. Elizabeths since June when a jury found he was not guilty of attempting to assassinate President Reagan last year because he was legally insane at the time.

The hospital's 18-page report, accompanied by more than 200 pages of medical records, was submitted yesterday to U.S. District Judge Barrington D. Parker, who presided at Hinckley's trial.

Parker is expected to hold a court hearing next Monday at which he will decide, in light of the hospital report, whether Hinckley should be released from St. Elizabeths, or whether he should be committed there indefinitely.

Parker has placed the hospital's report under seal. It was understood from various sources yesterday, however, that the doctors' conclusions about Hinckley's current mental state parallel the findings of psychiatrists who testified during Hinckley's two-month-long trial.

According to the sources, all the doctors who evaluated Hinckley at St. Elizabeths agree that he suffers from complicated and serious mental disorders--including depression and detachment from reality--that his character has not changed since he shot Reagan and that there is no sign that his delusional tendencies have ceased.

The doctors said in their report that, in addition to major depression, Hinckley displays symptoms of four types of personality disorders, primarily schizotypal personality disorder characterized by "magical thinking" and bizarre fantasies.

According to sources, the doctor's report contained numerous examples of Hinckley's "magical" notions about Foster, including his belief that she secretly admires him but is waiting for the publicity about his case to subside before she joins him.

Sources said the doctors also found that Hinckley has symptoms of narcissism, which is commonly described as a grandiose sense of self-importance and a constant desire for attention. The doctors said Hinckley also has features of schizoid and borderline personality disorders--illnesses characterized by, among other things, social isolation, impulsive behavior and manipulation, indifference and lack of emotion.

During Hinckley's trial prosecution psychiatrists had testified that Hinckley suffered from various personality disorders when he shot Reagan March 30, 1981, but not any that were severe enough to prevent him from abiding by the law or understanding that his attack on the president was wrong.

Those two issues were the key to Hinckley's insanity defense. He claimed he was mentally ill when he wounded Reagan and three others, and as a result could not conform his conduct to the law or appreciate that his acts were wrong.

Defense psychiatrists told the jury that Hinckley suffered from various forms of schizophrenia, a serious mental illness characterized by a severe break with reality, delusions and major depression.

Those psychiatrists also testified that when Hinckley fired on Reagan, he had a distorted notion that his act would somehow accomplish a "magical union" with Foster, the actress with whom he had been infatuated for years. In an unmailed letter to Foster left behind in a hotel room hours before the shooting, Hinckley said he hoped "with this historic deed to win your respect and love."

In an interview with The Washington Post after his trial, Hinckley said that if he was released from the hospital Foster would be the "only one there would be a problem with."

The doctors at St. Elizabeths labeled Hinckley's mental disorders according to classifications set out in a widely accepted but controversial diagnostic manual used by psychiatrists, which lists categories of mental illnesses by their symptoms.

According to the sources, the hospital's doctors said that if they had not been bound to those classifications, it was likely they would have diagnosed Hinckley as suffering from, among other things, borderline or ambulatory schizophrenia--diagnoses reached by several defense doctors who testified at Hinckley's trial.

Although he is legally entitled to the hearing scheduled before Parker next Monday, Hinckley has said that he might waive that right if the report from the hospital staff was not favorable to his release. No formal waiver has yet been filed with the court.

If Hinckley waives his right to the hearing, and Parker then commits him to the hospital indefinitely, he will remain there until the court finds that he is recovered from his mental illness and is no longer dangerous. Hinckley is entitled to a hearing every six months at which he could try to prove that he is ready to be released.

Both Hinckley's parents and his lawyers have said they would make no effort to seek his release from confinement until he is well and no longer dangerous.

The report on Hinckley's mental condition was submitted to Parker with a covering letter from Joseph Henneberry, director of the John Howard Pavilion at St. Elizabeths, where Hinckley is confined in a maximum security ward.

The report was signed by Henneberry, Dr. David Powell, the director of the post-trial branch at John Howard; Dr. Harold M. Boslow, the medical director there; Dr. Joan Turkus, a staff psychiatrist; Dr. Thomas J. Polley, a clinical psychologist, and Dr. Glenn Miller, who acted as a psychiatric consultant in Hinckley's case.