Behaviors among gay men have changed since the AIDS epidemic began, research from a long-term study of gay men in several cities indicates.

"There is a downward slope on risky behaviors in the (groups) being monitored today," said Ron Kessler, professor of sociology and program director of the Institute for Social Research at the University of Michigan. "It's the people in the middle range of risk who are doing most of the changing."

Kessler, speaking at the HUB earlier this week, said most of the change has been in men cutting down on their number of sexual partners. However, a core of about 10 to 20 percent of the men being studied have continued to maintain high-risk lifestyles. Kessler broke this group down into three categories in which individuals either feel they are invulnerable to the virus; believe it is too late for them and decide to enjoy life while they can; or choose not to think about the epidemic.

Kessler described the study as a multi-disciplinary approach to AIDS research. The Multi-site AIDS Cohort Study (MACS) is examining groups of gay men in six cities to determine how the AIDS epidemic has affected them, physically and emotionally, over the past five years.

The subjects in the study are men who, at the beginning of the study, averaged 35 years old with an average of over 16 years of education and $24,000 yearly salary in 1984.

Of this group, 55 percent of the men had intercourse in the month before the study was started and of that group, 90 percent did not use condoms.

Kessler described the study's sites in Los Angeles, New York, San Francisco, and Miami as high-risk sites and the sites in Baltimore and Chicago as medium-risk. Cohorts, or groups, of 1000 healthy gay men who showed no symptoms of AIDS at the beginning of the study are monitored at each site by a combination of a physical examination followed by an interview administered every six months.

Kessler's talk focused on the results from the Chicago cohort.

The study has also found higher stress levels in the gay men studied as compared to the average population, he said.

Kessler said the high stress levels stem not only from the AIDS epidemic but also from the fact that the gay population is currently undergoing many changes. He said stress from this source plays a larger part in affecting gay men's mental health than the fear of dying from AIDS-related illness.

There is no evidence these stresses have an effect on the onset of AIDS symptoms, he said. However, Kessler pointed out individuals who showed no symptoms but knew they had tested positive for HIV infection developed symptoms more quickly than those who showed no symptoms and had no knowledge of testing positive for HIV infection.

He added people who have recently been diagnosed as being positive for the HIV virus are developing symptoms sooner than people who were diagnosed in the past.

John Phair, of Northwestern University, is the director of the Chicago MACS and is responsible for collecting the medical data on the subjects. Jill Joseph, director of the Michigan Collaboration with the MACS, gathers the interview data.