Psychological tests given to John W. Hinckley Jr. after he shot President Reagan revealed scores similar to those recorded by severely ill patients confined to mental institutions, a psychologist told a federal jury yesterday.

The tests and interviews with Hinckley showed "a person who hates himself," Dr. Ernst Prelinger testified for the defense. He said Hinckley could "only live by clinging to someone else" and became desperate and suicidal when he had no one he could turn to.

Prelinger, a clinical psychologist at Yale University, told the jury that the chances are one in a million that a normal person would reach Hinckley's extremely high score on the "depression scale" of a standardized personality test given him.

Prelinger said Hinckley showed slightly above-average intelligence, but that he is "severely defective" in his development of what the psychologist called "the two most important human emotions"--sexuality and aggression.

Hinckley had "no sexual feeling he was comfortable with," and while he had aggressive fantasies, he was shy, unassertive and unable to demonstrate his aggressions in normal ways, he said.

Hinckley's responses on the tests showed he had grandiose ideas about himself as if he were "some kind of a special person," Prelinger testified.

For example, when Hinckley was asked to complete the sentence "The thing I like most about myself is . . . ," he responded: "the way I have so far managed to survive six crises of unbelievable magnitude." That was a reference to a book written by Richard M. Nixon, Prelinger told the jury.

Prelinger said the tests uncovered a great deal of evidence about Hinckley's continued obsession with actress Jodie Foster and his distorted fantasy that his attack on Reagan would achieve a romantic union with her.

"It was easier to fantasize about killing a president than introducing himself to Jodie Foster," Prelinger said Hinckley told him.

When given the incomplete sentence, "A man feels good when . . . ," Prelinger said Hinckley responded: "he manages to impress a woman and gain her admiration. Everything else is secondary because love comes with admiration." To another sentence that began "My conscience bothers me if . . . ," Hinckley responded: "I think about how much I have hurt Jodie Foster."

Prelinger said that when Hinckley was asked to state what he saw in sets of printed ink blots, known as the Rorschach test, he demonstrated severe depression and bizarre ideas as well as the kind of fragmented thinking characteristic of schizophrenics.

For example, Prelinger said Hinckley saw an unusually large number of "scary" visions in the ink blots, including skulls, bones, empty eye sockets and shrunken heads. In another case, Hinckley said he saw part of an ink blot as Greenland because the blot was green.

"That may not sound like much, but it is the exact response given by schizophrenics because Greenland isn't green," Prelinger told the jury.

Hinckley scored in the abnormal range on tests for all but one of nine types of disorders. His scores were exceptionally high on the scales for depression, schizophrenia (characterized by delusions and disordered thinking) and hypochondria (excessive concern with physical complaints that have no medical basis), Prelinger said.

He said Hinckley's scores in all three areas are well in the range of scores normally recorded by severely ill patients confined to mental hospitals.

So far, the jury at Hinckley's trial has heard testimony from two defense psychiatrists as well as Prelinger. All three said they concluded that Hinckley suffered from a form of schizophrenia at the time of the shooting. All three have testified that as a result of his mental illness, Hinckley was unable to obey the law or appreciate that his acts were wrong.

Like the psychiatrists, Prelinger, a specialist in emotional disturbances of young adults, drew his opinions about Hinckley's state of mind from a large base of information, including his own interviews with Hinckley as well as reports from other defense and prosecution psychiatrists.

As a psychologist trained in evaluating tests designed to help diagnose mental illness, Prelinger also for the first time gave the jury charts, scores and graphs to help them determine if Hinckley suffered from a mental illness when he shot Reagan.

The personality tests, which Prelinger said showed Hinckley's extreme depression, were administered by a government psychologist at the federal correctional institution at Butner, N.C., within five weeks after his attack on Reagan. Prelinger said that psychologist and two other consultants agree with him that the test scores are "valid."

Prelinger said that the tests given to Hinckley have built in safeguards to detect "cheating" and he said the results would not be skewed by the fact that they were administered while Hinckley was jailed and charged with the attempted assassination of the president.

"These scores are so high and so unusual" they show a longstanding condition well beyond the "blue mood of somebody held in prison."

In other developments yesterday, the defense, seeking to avoid delays in the trial, withdrew its request to present testimony from Dr. David Michael Bear about the results of sophisticated brain scans performed on Hinckley, which they said helped support Bear's conclusion that Hinckley suffered from schizophrenia. The government had objected to that evidence.

Bear, a Harvard University psychiatrist, completed three days of testimony yesterday. Under cross-examination, Bear denied that Hinckley had opted to shoot the president instead of returning home, testifying that "a man in psychotic distress . . . does not have options."