Depression doesn't speed AIDS onset, death.

Symptoms of depression that often strike people infected with HIV, the AIDS-causing virus, appear to have little effect on when they develop the disease or how long they live, two new studies find.

"The development of HIV-related physical symptoms increases the likelihood of depression, but... depressive symptoms do not in themselves increase the progression of HIV disease," argues an editorial written by physician Samuel Perry and psychologist Baruch Fishman, both at Cornell University Medical College in New York City.

Both studies and the editorial appear in the Dec. 1 JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION.

One of these studies, by Jeffrey H. Burack and his colleagues at the University o[ California, San Francisco, extends and revises findings first reported at the VIII International Conference on AIDS in Amsterdam in 1992 (SN: 7/25/92, p.53).

Initially, Burack and his co-workers found that alter three years, depressed patients had twice the death rate of a nondepressed group. But in the new report they note that after 66 months, "neither overall depression nor affective depression was significantly associated with earlier AIDS diagnosis or earlier mortality."

The researchers emphasize a finding unique to their study. which suggests that depression affects the immune system. They found that over the course of the study, the number of CD4 immune cells declined less rapidly in the 227 non-depressed subjects than in the 50 volunteers who reported suffering from symptoms of depression when they started the study. Declining CD4 cell counts indicate that the HIV infection is progressing.

The CD4 cell counts of depressed volunteers declined between 34 and 38 percent faster than those of the non-depressed subjects, the researchers found. The team is now investigating why CD4 cell counts drop faster in depressed AIDS patients.

But in actual numbers, these differences in CD4 cell declines are quite small, Perry and Fishman note in their editorial. And while statistically significant, the declines may be the result of chance or the method they used to measure CD4 cells.

"It's not clinically meaningful," agrees Robert H. Remien, a psychologist at Columbia University.

Indeed, an eight-year study involving 365 depressed and 1,858 nondepressed volunteers failed to confirm the San Francisco findings. Constantine G. Lyketsos of the Johns Honkins University School of Medicine in Baltimore and his colleagues found similar rates of CD4 cell decline among depressed and nondepressed participants in the Multicenter AIDS Cohort Study, they report. But they, too, found "no evidence that depressive symptoms independently prognosticate worse outcomes in HIV infection."

The differences between the two studies' findings concerning depression and the decline in the number of CD4 cells probably stem from "some difference in the sample," says Donald Barrett, a coauthor of the Burack study and a statistician and sociologist at the University of California, San Francisco.

The volunteers in the Lyketsos study had lower CD4 counts to begin with, which suggests that they were less healthy, Barrett says. "In a less healthy sample, there's less room for CD4 cells to decline, he notes.

Lyketsos says that Burack's finding may have been caused by chance, as that group measured CD4 cell decline less often and had fewer subjects than his study did.

Lyketsos and his colleagues emphasize that their findings on depression and HIV should not halt further research on the topic. In fact, "there may be some subtypes of depression that may be more related to survival" than other types, Lyketsos explains.