HIV infection among various populations, and may ultimately provide the basis for intervention programs aimed at curtailing further transmission.

Among injection drug users, in particular, it is also critical to develop effective epidemiologic surveillance mechanisms for identifying new drug injectors within populations, to be able to track trends in drug injection over time. Due in part to difficulties in identifying and gaining access to the population groups initiating or relapsing into drug injection, most of the HIV epidemiologic studies among drug users to date have focused on long-term, chronic injectors. While older injectors have generally had higher documented levels of prevalent HIV infection, the group of younger, new injectors may be at particularly highrisk of acquiring and transmitting HIV infection, and thus may be an important group for preventive interventions in the future.

Another population at potentially highrisk for HIV infection, but one that has been neglected in the research until very recently, is the seriously mentally ill (Box 2.1). Recent seroprevalence studies among the seriously mentally ill reveal rates of HIV infection higher than the general population. Because risk among this group relates to comorbidity of mental illness, substance abuse, and unprotected sex, the seriously mentally ill are an important population for monitoring concurrent epidemics.

As has been noted, HIV infection is spread through specific behaviors, particularly sexual intercourse without barrier protection and the sharing of contaminated drug injection paraphernalia. In order to understand the potential course of the epidemic, social and behavioral research has focused on determining the likelihood that infected individuals in one group will have contact with uninfected individuals in the other; identifying the contexts that influence risk taking; investigating whether people in high- and low-risk groups are adopting recommended preventive behaviors; and examining how the spread of HIV infection will be altered by changing patterns in concurrent epidemics of drug use and infectious diseases.

The risk posed by unprotected sexual intercourse is linked to the probability that the sexual partner is HIV infected. Several studies have examined the risk status of sex partners of people who are neither homosexually active men nor intravenous drug

FRONT MATTER (R1-R18)

EXECUTIVE SUMMARY (1-38)

1 INTRODUCTION (39-44)

PART I RESEARCH FINDINGS AND OPPORTUNITIES (45-46)

2 UNDERSTANDING HIV TRANSMISSION (47-77)

3 UNDERSTANDING THE DETERMINANTS OF HIV RISK BEHAVIOR (78-123)

4 DISEASE PROGRESSION AND INTERVENTION (124-154)

PART II MANAGING THE AIDS RESEARCH PROGRAMS AT NIAAA, NIDA, AND NIMH (155-156)

5 THE CONTEXT OF AIDS PROGRAMS AT NIAAA, NIDA, AND NIMH (157-185)

6 RESEARCH FUNDING, PROGRAMS, AND PRIORITIES AT NIAAA, NIDA, AND NIMH (186-239)

7 LINKAGES BETWEEN RESEARCH AND SERVICES (240-256)

BIBLIOGRAPHY AND REFERENCES (257-296)

APPENDIXES (297-298)

A Grants Analysis Methodology (299-304)

B Abbreviations and Acronyms (305-308)

C Acknowledgments (309-314)

D Contributors (315-326)

INDEX (327-338)