At least 50 times in the past few years, Dallas psychiatrist James Grigson has appeared in court for prosecutors seeking the death penalty and has predicted that criminal defendants would, without question, always be dangerous.

And at least 50 times, juries have heeded his words and sentenced the defendant to die.

By now, it is a routine. Grigson examines the defendant for about 90 minutes, and later appears before the jury, when it is considering whether to impose the death sentence.

His testimony is crucial, because the sentence cannot be imposed unless the jury finds that the convict presents a future danger. Grigson testifies each time in roughly the same language, describing the person as a sociopath or a "severe sociopath . . . [who] . . . will continue his previous behavior," and will ". . . commit other similar crimmal acts if given the opportunity to do so."

Already famous in Texas as a result of this practice, Grigson now is perhaps the most controversial psychiatrist in the United States because one of his appearances has been brought before the Supreme Court.

He is defended by prosecutors and government lawyers in texas, who say that what he does is an accepted part of the adversay system of crime and punishment -- that what he is doing is expressing an opinion that can be accepted or rejected by a jury.

"Expert witnesses are bought and sold," said Douglas Becker, Texas' assistant attorney general. "The prosecution buys them, and the defense buys them. It's up to the jury to decide which is believable."

But Grigson is attacked, in unprecedented fashion, by his profession. The literature of psychiatry, the American Psychiatric Association has told the Supreme Court, "establishes that such predictions are fundamentally of very low reliability" and should not be allowed. At stake, the association said, is the quality and integrity of the practice of psychiatry in the criminal justice system.

Grigson no longer is willing to defend himself publicly. He is tired, he says, of being called. "Dr. Death" by reporters who interview him.

Texas, like other states, has not executed anyone in years, but about 130 inmates are now on death row. One is Ernest Benjamin Smith, and his case, Estelle vs. Smith , is now before the Supreme Court.

At issue is whether defendants can be forced, as Smith was, to submit to an examination that is then turned against them, and whether Smith had "the right to remain silent" and to consult a lawyer about the interview, the same right suspects have when questioned by police.

The question of use of such testimony, under any circumstances, is not before the Supreme Court, although it is the focus of much of the debate outside the court.

At 26, with one conviction for possession of marijuana, Smith participated in a Dallas convenience store robbery in which the storekeeper was shot and killed. During the robbery, Smith said he thought he saw the storekeeper reach for a gun. He shouted to an accomplice, who fired, killing the storekeeper.

There was conflicting testimony about whether Smith attempted to shoot the storekeeper first with his own gun, which clicked harmlessly when he pulled the trigger. But there was no question that it was not Smith who fired the fatal bullet.

While he was in the Dallas County Jail, awaiting trial, Smith first met Grigson. A graduate of Southwestern Medical School, Grigson was becoming an expert on criminals. He had examined about 8,000 people charged with crimes before being asked by the Dallas judge on Feb. 18, 1974, to examine Smith to help determine his competence to stand trial.

Smith was brought from his cell to a small eighth-floor room furnished with a table and two chairs. He was given no choice about whether to talk with Grigson, no lawyer to advise him during the interview, and, according to the psychiatrist's later testimony, he spoke freely about himself and the charges against him.

Grigson later said he spent about "an hour and a half or thereabouts" with Smith. "I don't exactly recall. . . . His behavior was completely normal. He was very pleasant, very cooperative, very polite."

Smith did not know that those 90 minutes would help determine whether he lived or died. This dawned on him and his lawyers a month later, after he was convicted of participation in the murder.

Smith was sentenced March 11, 1974. Grigson was the government's only witness.

Under prosecution questioning, Grigson described his 90-minute interview with Smith: "The one significant fact which was present was i could find absolutely no signs of any remorse or any type of guilt feelings."

Then, for the benefit of the jury, he defined sociopaths "as . . . individuals that do not have a conscience that most of us develop at an early age. They have no . . . guilt feelings, remorse feelings."

Then, in a routine that would become the standard exchange between Grigson and prosecuting lawyers, the questioning zeroed in on the subject:

Question: "You're saying he [smith] is a very severe sociopath?"

Answer: "Yes, sir, I am."

Question: "No conscience, no remorse, no guilt feelings?"

Answer: "No. He has none."

Question: "Now, Dr. Grigson, what is your prognosis in this case?"

Answer: "Oh. He will continue his previous behavior, that which he has done in the past. He will again do it in the future. . . . If anything, it would only get worse. . . . This is not what you would consider a stage. This is a way of life. Just as you work every day, well, his personality comes out in his behavior."

After a few more answers, elaborating on the first, the prosecutor moved in for the crucial thrust.

Question: "Now, Dr. Grigson, do you have an opinion as to whether or not there is a probability that the defendant . . . will commit criminal acts of violence that will constitute a continuing threat to society?"

Answer: "Yes. . . ."

Question: "And what is that opinion?"

Answer: "That certainly Mr. Smith is going to go ahead and commit other similar or same criminal acts if given the opportunity to do so.

Smith and his attorney, John Simmons of Dallas, were surprised by Grigson's testimony. A U.S. District Court judge in Texas, ruling on Smith's habeas corpus petition, set aside the death sentence because of that surprise, and the 5th U.S. Circuit Court of Appeals affirmed the lower court.

Defense lawyers should be notified properly of the testimony so they can prepare to impeach it, the courts, said. Beyond that, the defendant should have rights simialr to those he has when being questioned by police: the rights to remain silent and to consult an an attorney.

The use of psychiatry to determine sanity at the time of a crime and to establish competence to stand trial has been controversial enough. Use of psychiatry to predict future behavior raises even broader questions.

The American Psychiatric Association, in a "friend-of-the-court" brief in the Smith case, said that, "Such predictions are fundamentally of very low reliability, and psychiatric testimony and expertise are irrelevant to such predictions. . . . Psychiatric testimony on the issue of future criminal behavior only distorts the fact-finding process."

The Texas attorney general, who is defending the practice before the Supreme Court, acknowledges that criticism. But in the context of the jury system, Assistant Attorney General Douglas Becker said, Grigson is just another expert witness.

"It's for the jury to decide what's reliable and what isn't. If testimony is not worthy of belief, it's the jury that's supposed to make that decision," he said.

In court testimony, Grigson defended his technique. He said he gives a "mental status examination" to defendants, examining "thinking, feeling and behavior." He studies "the way a person walks into the interview room, the way they sit, their attention or lack of attention to personal appearances . . . whether thoughts come out in a logical rational sequence . . . their tone of voice, do they know who they are and what's going on about them?" t

In determining whether Smith was a socipath, Grigson said, "The one significant fact which was present was I could find absolutely to signs of any remorse or any type of guilt feelings."

He drew that conclusion, he said, from the way Smith described the crime. "He told me that he walked around over this man who had been shot, didn't check to see if he had had a gun or if he was alive or dead. He didn't call an ambulance. . . .

"This is . . . coldblooded disregard for another human being's life. . . ." He should have had some "guilt-type feelings," Grigson concluded.