When the prosecutor needled him good-naturedly, Henry Howard smiled ever so faintly. When the psychiatrist described Mr. Howard's ghastly crime of nine years ago, his face registered nothing at all.

But, according to testimony in a Baltimore courtroom yesterday, that limited range of expression -- what the psychiatrist described as Mr. Howard's "lack of affect" -- is virtually the only residual symptom he retains of the raging mental illness that propelled him to murder his mother and three other family members in their Southeast Baltimore home on a sultry summer evening.

Yesterday, the 30-year-old Mr. Howard,in a dark, double-breasted suit, sat in a Windsor chair with his hands folded on his stomach. He listened attentively as the state of Maryland began offering testimony that his disease, diagnosed immediately after his crime as paranoid schizophrenia, was now in remission.

The delusions, the hallucinations, the messages from God and Satan are all gone. He is ready, the state is now arguing, for a conditional release from Clifton T. Perkins Hospital Center for the criminally insane, where he was sent in 1983 after being found not guilty by reason of insanity.

Based on his steady progress at the hospital, his insight into his ZTC own illness, his success in a work-release program and his strong relationship with his therapists,Christiane Tellefsen, the acting superintendent of Perkins, testified that "there has been a tremendous improvement in his mental state and condition."

"My opinion is that he would not be a danger if released under . . . conditions," she told Baltimore Circuit Court Judge Ellen Lipton Hollander, who will ultimately decide if Dr. Tellefsen and her staff are right.

The Baltimore state's attorney's office is opposing Perkins' petition, and yesterday Assistant State's Attorney Edwin Wenck reminded Judge Hollander of the gravity of her decision. No doctor, he warned, could guarantee that Mr. Howard would not again spin out of control.

"Mr. Howard is capable of [deteriorating] and killing again," he said in opening remarks.

Dr. Tellefsen was the only witness in the first of what is expected to be four days of testimony during the next month.

Mr. Howard himself is expected to take the witness stand, and his testimony, along with that of other witnesses, promises to give a unique glimpse of both his life and the internal operations of a hospital largely unfamiliar and mysterious to the general public.

Dr. Tellefsen opened that portrait with a haunting description of Mr. Howard's peculiar, twisted upbringing in a household full of deranged people. Four of the five people with whom he lived -- his mother, his aunt, his uncle and his older brother -- were themselves paranoid schizophrenics, Dr. Tellefsen said. All of them had been admitted to state mental hospitals.

"The family used to joke about having family reunions in Crownsville," said Dr. Tellefsen, referring to a state psychiatric hospital.

The boy grew up, Dr. Tellefsen said, in a "cold, hard, unloving, peculiar strange environment." On one occasion, after Mr. Howard had cut his head and was bleeding, his mother, rather than take him for treatment, remarked, "That's what happens when you eat ketchup."

He performed poorly in school, quitting altogether in the eighth grade, and later told therapists that school was "too violent. I wasnever violent. The most violent thing I did was to kill my family."

He formed no relationships. He spent almost all his time alone and unsupervised. Often he sat for hours in a chair rocking back and forth, according to hospital records. Other bizarre behavior including starting fires and torturing animals.

For some stretches of time, Dr. Tellefsen said, Mr. Howard lived in foster homes, but at age 16 he returned home and resumed his solitary existence. During that period, his condition worsened considerably. He hallucinated and had delusionary thoughts. He believed, for example, that God and Satan talked to him through the radio. He also came to believe people were intent on harming him, and for no apparent reason he became convinced that he was dying.

In that period, Dr. Tellefsen said, Mr. Howard began harboring thoughts of murdering his family. He later said that Satan told him he would win the state lottery, which would provide him with the means to accomplish this mission. Oddly enough, his grandmother did win $25,000 in the lottery, and with the $3,000 she gave him, he purchased the gun he used to kill his family.

On July 29, 1982, at age 21, he walked from room to room and shot his uncle, his aunt, his grandmother and his mother. He later told his counselors that he had planned to kill many others as well -- policemen, firemen, schoolchildren, his brother -- but he was arrested before he had the chance.

The delusional thinking continued into his stay at Perkins hospital, Dr. Tellefsen said, but within two years the therapy beganto bring about positive signs. Because his childhood had been so grotesquely abnormal, she said, it was at Perkins that he began progressing through the developmental stages normal for a child and adolescent but wholly absent in his life. He learned how to form relationships, she said, how to trust and interact with people. As he did so, she said, his delusional thinking disappeared altogether.

His recovery, she added, was also accomplished without the use of medication, which she said was unusual for schizophrenics and an added reason for optimism.

Although Dr. Tellefsen described Mr. Howard's progress as slow and steady, she said the hospital had been ready to apply for his conditional release three years ago. Until now, he has refused.

But his progress continued, she said. Three years ago, he moved into a Baltimore halfway house operated by Perkins, and he has held a janitorial job at the Department of Motor Vehicles. She said he has also withstood stresses -- failure in a college-level course and various physical ailments -- that could have triggered deterioration.

Dr. Tellefsen also said that if Mr. Howard's symptoms reappeared, they would become readily apparent to any trained therapist.

If Judge Hollander grants Mr. Howard's release, his life will actually change very little, at least initially. He would still live in the halfway house. He would also be required to continue in frequent therapy sessions and submit to monitoring. He would also be required to get clearance for virtually all life changes from his therapists, from marital plans to job changes to housing.