By Julie Rovner Special to The Washington Post

Once again, science is applying its quantitative methods to prove something pet owners have known for years: Pets are good for you.

Studies have -- among other things -- linked pets to increased life spans in heart-attack victims, lowering of blood pressure and marked progress in mentally retarded children.

The use of "animal-facilitated therapy" (better known as pet therapy) is growing at such a rate that a conference at the University of Pennsylvania on the human/companion animal bond drew some 500 veterinarians, psychiatrists, animal behaviorists and anthropologists to examine the importance of pet animals and their relation to human health.

"Pets have a real place in our society," says Dr. Alan Beck, director of the university's Center for the Interaction of Animals and Society. "What we're trying to do here is make the concepts of animal ownership conform to science."

Dr. Michael McCulloch, a Portland, Ore., psychiatrist active in a number of pet-therapy programs, sees the beneficence of pets going beyond mere scientific curiosity. He wants to see the studies used to convince state legislators and hospital and nursing-home administrators to give pet-therapy programs a try.

While pet therapy includes such activities as horseback riding for the physically and mentally handicapped and allowing prison inmates to have pets, possibly the most popular program is one in which animal shelters or humane societies bundle off several animals for regular visits to nursing and retirement homes.

In the Washington area, the Arlington Animal Welfare League runs a pet-therapy program that delivers animals for hour-long visits in seven area homes.

"The program began almost by accident," says AAWL executive director Martha Armstrong. "Last Christmas was the first time in my life I couldn't get home, and I thought it would be nice to do something humanitarian."

Armstrong and two of her staff members took a few animals from the shelter to the Hermitage, an Alexandria nursing home. The response was so enthusiastic that after consultation with the home's activities director and the health department, permission was granted to make the program a regular event.

"After that," says Armstrong, "word began to get around and homes began calling us to see if they could have visits too."

A typical visit begins in one of the back rooms of the AAWL's shelter, where a few puppies and kittens--selected for quiet temperaments--are taken from their cages and their nails clipped. ("So they don't catch on some little old lady's sweater.") The four or five animals are put into airline carriers and delivered by volunteers (without whom there would be no program, says Armstrong).

The animals are usually taken into an activities room at the home, where each volunteer is responsible for a single animal, carried around the room for patients to pet, hold or simply admire.

"You can't believe the way these people look forward to these visits," says Donna O'Hanlan, activities director at Arlington's Camelot Hall. "They talk about it all the time, and ask me 'When are the animals coming back?'

"When the animals come through that door, there's not a single face that's not smiling. These animals have brought purpose back into their lives.

"For the most part, when they come into a facility like this, they've had to leave the things they love behind. What we've done here is brought back something into their lives that they can love, even if it's only for an hour once a month."

Dr. Leo Bustad, dean of Washington State University's Veterinary School and considered by many the father of modern pet therapy, first became interested in its benefits when he smuggled a dog in to visit his mother in a nursing home.

The other patients, he says, "all wanted to touch the dog. It was like they were starved for attention."

The result was Bustad's People-Pet Partnership Program, which in 1975 placed its first cat in a nursing home.

While pet-therapy programs have been documented as far back as 1792, when a British group founded a retreat near York, England, pet therapy in this country has grown only in the last 10 years.

"The beauty of an animal is that it's eternally young," says Bustad. "Animals make no judgments, and they are always accepting. They don't care how you look."

Portland psychiatrist McCulloch divides the beneficial effects of pet therapy into three categories: physical, social and psychological. Although the physical benefits are more dramatic--such as the measured lowering of blood pressure when a person touches a pet--the psychological and social benefits, though more difficult to document, point in the same direction.

"Pet therapy works in an institutional situation because it's a very stereotyped situation, with no room for novelty, individuality or privacy," says McCulloch. "Animals give a sense of time, and help to orient people."

According to McCulloch, when an Ohio hospital for the criminally insane allowed inmates to have pets, they noted a marked decrease in violent attacks, suicide attempts and the need for medication.

Another bonus, according to AAWL's Armstrong: "Try as we do, we simply don't have enough time for each animal, and with the program the animals have the chance to get out of their cages and be touched and played with. It's really therapy for everyone."

Despite the enthusiasm, however, McCulloch stresses the need for close supervision. "A badly run program," he says, "can actually do more harm than good."

"This isn't for everyone," says Beck. "Animals in therapy programs should be prescribed as one would a drug, with contraindications in some situations."

Meanwhile, the Arlington program seems to be going well. O'Hanlan recounts this favorite story about a woman recovering from a stroke:

"For months she'd had only three words in her vocabulary. Then, the day she was participating in the program, she was given a kitten to hold. As the volunteer lifted the animal out of her lap, she pointed and said, 'I love that one.' "