Psychologist David Fox and his family were standing in their driveway in suburban Los Angeles one evening three years ago when a 30-year-old former patient of Fox's stepped from the bushes and opened fire on the family with a .38 caliber pistol. As Fox's four young children cowered in fear, Fox and his wife, who were both wounded, tackled the woman, punching and biting her as they wrestled the gun from her hand. The woman, who had stalked and harassed the family for five years claimed that Fox had belittled and insulted her in therapy. She has been sentenced to life in prison; Fox and his family have recovered.

Such violent assaults are rare, but attacks against therapists -- and sometimes their families -- are of growing concern to mental health workers. That concern was heightened recently by a June 1 attack on Fairfax psychiatrist Paul J. Peckar, who was severely injured when a letter bomb addressed to him exploded as he was opening it in his office. Police have made no arrests in the case. Although authorities are examining his patient records, they say they do not know whether the bomb was sent by a patient.

The vast majority of patients who are being treated for psychiatric problems pose no risk to their therapists or anyone else. But a small group of patients threaten and sometimes kill the people who are trying to help them.

Such violent attacks have included: Last year, 36-year-old Santa Monica social worker Robbyn Panitch was stabbed to death by a former patient who attacked her in her office. The man was found incompetent to stand trial and was sent to a state mental hospital. Social worker Eva Gawronski, her husband and infant daughter were attacked in their Los Angeles home by one of her former patients in 1982. The man waited until the family entered the house, poured gasoline through a window and lit it with an emergency traffic flare. Gawronski's husband died as a result of burns; she was severely disfigured and was hospitalized for 10 months. Her daughter, rescued by a neighbor, was unharmed. The patient told police he wanted Gawronski to suffer as he had. He is currently in prison.

Incidents like these have prompted the American Psychiatric Association to form a task force. "We're recognizing that this is a problem, not only for psychiatrists but for other mental health professionals as well," said Kenneth J. Tardiff, professor of psychiatry at Cornell Medical College in New York and a member of the task force.

Exactly how many mental health workers are injured by the people they treat is not known, largely because no official reporting system exists to track such incidents. "The AMA {American Medical Association} and the APA don't really find out about all these things," said Burr Eichelman, clinical director of the Dorothea Dix Hospital in Raleigh, N.C., and a member of the APA task force.

About half a dozen studies, including a 1976 report from the University of Maryland, suggest that an estimated 40 percent of psychiatrists "are assaulted at some time in the course of their career, primarily when they are young," said John Lion, clinical professor of psychiatry at the University of Maryland School of Medicine in Baltimore. Other studies show that about 80 percent of psychiatric nurses, 20 percent of social workers and 10 percent of clinical psychologists are attacked by a patient at one time in their career. These attacks range from being shoved to being stabbed by a patient, and most occur in hospitals.

Mental health professionals aren't the only ones at risk. Teachers, nurses, judges and lawyers are also victims of violence. "It's not a unique problem to the healing professions," Lion said. "But attacks happen more often in the mental health profession than in other medical specialties."

"It has to do with the power of the mental health specialist," he said, as well as with the "nature of the intimacy" between therapist and patient.

Younger psychiatrists seem to be most vulnerable both because of their inexperience and the kinds of patients they treat. It is the psychiatrist-in-training who generally treats hospitalized patients -- those who are likely to have more severe problems and are more likely to be violent. "They are likely to be more accepting of difficult patients {which may place them in higher risk situations} and yet their inexperience may provoke a patient inadvertently to attack," Tardiff said. Tardiff and others say that inexperienced mental health workers may ignore important cues and sometimes are not as adept at talking with patients about sensitive subjects.

Certain situations seem more likely than others to trigger violence. The decision to hospitalize a patient or to medicate someone can provoke an attack. So can making a choice in a custody case, deciding that a patient is not too disabled to work or even asking about an unpaid bill. "Usually, something is happening that the patient doesn't want to have happen," Tardiff explained.

In other cases, counseling sessions may enrage patients who are delving into painful memories. The patient may also project feelings about someone else onto the therapist.

Some threats are merely verbal and not very specific. "They say, 'I'm going to get you!' or 'I feel like hurting you,' " said the University of Maryland's Lion. Others may send letters or make threatening phone calls.

Most attacks occur on psychiatric wards and in emergency rooms and involve minor scuffles, a push or a quick punch. Fewer attacks occur in private offices and mental health clinics, where there is less security. But, these assaults are more likely to involve a weapon and therefore have a greater potential for violence.

Santa Monica psychiatrist George Seeds was attacked last January by the husband of a former patient. Seeds found the man waiting with a gun in his outer office at noon. The 74-year-old assailant, whose wife had sued Seeds for malpractice and had recently committed suicide, locked the 60-year-old psychiatrist in his office, tied his feet together and forced him to lie face down on the floor. Then holding a gun, the man squirted acid in his face. Seeds lunged at the man, they struggled and Seeds eventually strangled his assailant. The case was investigated as a homicide, but authorities did not press charges against Seeds, deciding that he acted in self-defense. Seeds was hospitalized and has recovered.

Attacks by older patients are unusual, experts say. Most attackers are "young males, who have such diagnoses as schizophrenia, antisocial personality and borderline personality disorder," according to Tardiff. Sometimes, the therapist is viewed as an authority figure and inspires rebellion.

Reducing assaults requires acknowledging the problem. "We as a profession have a problem with this whole issue," said psychologist Gregory Van Rybroek, who works at the Mendota Mental Health Institute in Madison, Wis., which runs a pilot program to reduce aggression and violent attacks in state mental hospitals.

What frequently happens, Van Rybroek said, is that therapists "deny the issue of aggression."

Violent patients are usually secluded and medicated, and staff members are angry and afraid of them. "These patients never get better because no one ever wants to take them on," he said.

At Mendota, the most violent and aggressive patients are gradually integrated back into the regular psychiatric wards. "We sprinkle these patients around," Van Rybroek said. "Everyone gets a few aggressive patients."

The staff also receives special instruction in dealing with the patients and attends a group program to talk about the fears they arouse. In addition, the wards are stripped of dangerous objects -- including telephones and free-standing lamps -- that have been used as weapons. Patients with a continued history of violence are required to wear restraints that restrict movement.

Better training and more safeguards may help reduce the problem in hospitals and private practices. "There's no real standardized training for psychiatrists," said William R. Dubin, deputy medical director of the Philadelphia Psychiatric Center and chairman of the APA task force on clinician safety. "They spend three times more time hearing about suicide management than about aggression management."