Psychology, the science of human behavior, faces an unusual challenge in the AIDS epidemic: In the absence of a cure or vaccine, society has turned to psychologists to figure out ways of controlling the disease by changing how people behave.
Psychologists are studying why people do what they do: Why do they share needles or engage in sexual practices linked to the spread of AIDS? Why do some people, well aware of the protection offered by condoms, continue to have unprotected sex?
They are also exploring one of medicine's most provocative questions--how the mind influences the body's battle against disease. Specifically, can some behavior bolster the immune system, delaying the effects of the human immunodeficiency virus, which causes AIDS.
"This is an area of intense interest to psychologists," said Gail Ironson of Stanford University, speaking recently at the American Psychological Assn. convention in Atlanta. She cited what she called the potential for psychologists to make an impact on the epidemic.
So far, success at changing behavior has been mixed.
Risky sexual practices among gay men are decreasing; intravenous drug users are sharing needles less often. But it is proving more difficult to persuade heterosexuals and drug users to protect themselves and their partners by using condoms, researchers say.
One problem lies in the way people think about dangerous but relatively unlikely events, such as becoming infected with HIV, said Don Des Jarlais of the New York State Division of Substance Abuse Control. Some people simply ignore such risks; others exaggerate them. Either way, those dangers become difficult to discuss, he said.
Furthermore, AIDS education may be insufficient to change behavior, reported Vickie Mays, an associate professor of clinical psychology at UCLA. Mays has found that young black women change their habits only when they come to see themselves as personally vulnerable.
"It's one thing to have knowledge about AIDS and risk," said June Reinisch of the Kinsey Institute for Research in Sex, Gender and Reproduction at the Atlanta convention. "To perceive your own risk is another matter."
Questions being examined by psychologists include:
* In what ways do people place themselves at risk of infection?
* How can people be persuaded to change? What works with which groups?
* What stress-management techniques might bolster the immune system, the body's defense network, which is crucial in fending off the AIDS-related infections that lead to death?
Current sexual practices nationwide are poorly understood, in part because there has been no comprehensive survey since the 1940s, researchers say. However, a number of smaller studies are beginning to sketch a picture of habits that may be helping to spread the AIDS virus.
One study by Reinisch found that 45% of the 262 lesbian women studied reported having had sex with men since 1980. Because many of those men were bisexual, those contacts may be a growing conduit for the AIDS virus to infect low-risk groups like lesbians, she said.
A study of gay male teen-agers found them well-informed about how the virus is spread, reported D. Bruce Carter, a Syracuse University psychologist. But they were "highly unlikely" to take precautions because most of their sexual encounters were anonymous.
Similarly, a study of Cleveland residents, mostly minority women, found that 73% of those questioned knew condoms should be used as protection. But only 12% reported having used them in the past year with all their partners.
How best to change people's habits varies from group to group, researchers find.
Mays of UCLA suggests that "one-shot interventions" like AIDS-prevention brochures won't change behavior, at least among the women she studied. Something is needed to help them develop the "emotional focus" necessary to change something as highly charged as sexual relations.
Other researchers, finding that many people report that television is their primary source of information about AIDS, are testing the effectiveness of continuously broadcasting videotapes in the waiting rooms of inner-city health clinics.
Thomas J. Coates of UC San Francisco, who has documented the dramatic changes in sexual practices among gay men, contends that the most effective approach is communitywide. It should focus on changing social norms, which create peer pressure, rather than simply changing the individual.
Researchers agree that approach has succeeded among gay men.
"I think it's safe to say at the moment that the epidemic of new infections is coming to a halt in New York City," said John Martin, a psychologist at Columbia University, referring to gay men. "But new AIDS cases are not."
Because people infected with human immunodeficiency virus can go for years before developing AIDS symptoms and because even people with full-blown AIDS are living longer than in the past, attention has turned to ways of delaying the onset of symptoms and slowing the progress of the disease.