A 22-year-old Reston man who clubbed his mother to death with a baseball bat after ramming his car into his parents' home last year was found not guilty yesterday by reason of insanity.

A psychologist and psychiatrist who examined Alfred L. Head testified that he was suffering from schizophrenia and bipolar disorder--illnesses characterized by delusions, hallucinations and manic behavior--when he killed his mother, Zona N. Head, 56, on July 30, 1998, claiming he had been ordered to do so by a chess piece.

The prosecution's psychologist and the defense team's psychiatrist concluded that Head did not know right from wrong when he crashed his 1990 Pontiac into the living room of his parents' split-level brick home, where his mother was watching television, and then, finding her unhurt, hit her several times in the head with a baseball bat. She was found dead at the scene.

Friends testified during the one-day trial that Zona Head, an office manager at the Reston Chamber of Commerce, had been distraught for months over her son's deteriorating mental condition. Karen Keeffer, a forensic psychiatrist who examined Alfred Head, said that he had suffered from mental illness since 1993 and that his condition had worsened in recent years.

"He was getting more bizarre in his thinking, and he was clearly out of touch," Keeffer said.

William J. Stejskal, a psychologist who also examined Head, testified that the Reston man attempted suicide in May 1998 by trying to saw through his throat with a serrated knife--"one of the most serious suicide attempts I have ever seen," Stejskal said.

During yesterday's four-hour court proceeding, friends and mental health experts painted a picture of an outgoing young man with above-average intelligence who increasingly began to show signs of paranoia. His former girlfriend testified that Head told her his father was conducting an experiment on him and that he was being watched constantly.

Head's father was out of the country when his wife was killed.

Efforts to keep Head in treatment and on medication often failed, because he had a way of manipulating his doctors and denying he had a problem, Stejskal said. "He's someone who is able to reel it in for a while and convince others he is okay," he said.

Keeffer said Head told her he was ordered to kill his mother by a chess piece during a game at a Reston coffee shop. Head believed he had a wife and children who were being kept from him by his parents.

"He felt he was getting a message," Keeffer said. "He saw this [killing his mother] as the only chance he had to set himself free. In his mind, this was his way of protecting his children."

Prosecutors did not oppose Head's insanity plea. Fairfax Circuit Court Judge Stanley P. Klein sent him to Central State Hospital in Petersburg for a 45-day evaluation.

Family and friends showed no emotion at yesterday's proceedings. Afterward, Head's father said "justice has been served."

"I'm glad to have my son have a second chance at life," said Alfred F. Head, a Foreign Service officer who was in Portugal when his wife was killed. "We love him, and we'll stand by him."