The co-directors and program faculty of the Visiting Professor program serve as a mentor to one or more of the CAPS Visiting Professors.


co-director Marguerita Lightfoot, PhD
co-director Tor Neilands, PhD

program faculty Emily Arnold, PhD, MPH
program faculty Cherrie Boyer, PhD
program faculty Mallory Johnson, PhD
program faculty Jim Sorensen, PhD
program faculty Bill Woods, PhD



Marguerita Lightfoot, PhD

Professor in Residence | Director of CAPS

Dr. Marguerita Lightfoot is Director of the Center for AIDS Prevention Studies (CAPS) and Director of its Technology and Information Exchange (TIE) Core. She is also head of the Division of Prevention Science in the Department of Medicine. Dr. Lightfoot is a counseling psychologist whose research has included HIV prevention work in the juvenile justice system and with runaway and homeless youths in Los Angeles. One particular focus of her research with adolescents has been delivery of HIV preventive activities on computers. In addition, she has worked as a Mental Health Clinician at a clinic that served low-income people of color. She’s conducted psychotherapy with predominately African American and Latino adults, couples, and families infected and/or affected by HIV. She is particularly interested in developing cost-effective interventions that are easily translatable. She has a unique ability to determine the programmatic needs of vulnerable populations and develop programs that are cutting-edge and likely to successfully engage these populations. A notable research project has been adapting interventions to reduce HIV-related risk among urban street youths and youths living with HIV in Uganda.

Click here for more information on Dr. Lightfoot.

Torsten B. Neilands, PhD

Professor, Department of Medicine 

Dr. Neilands is the Director of the CAPS Methods Core, which provides technical support to CAPS scientists in qualitative and quantitative methods as well as in behavioral and biomedical measurement. Since beginning work at CAPS in 2000, he has served as a data analyst, statistical consultant, and co-investigator on more than fifty research projects, most of which have been NIH-sponsored. His areas of interest include social and behavioral science statistical methods (e.g., latent variable methods and scale development); STD awareness, education, and prevention; HIV medication adherence issues; HIV/AIDS stigma and how to reduce it, and stress and coping theory.

Dr. Neilands obtained a bachelor’s degree in English Literature and Psychology at University of California at Santa Cruz. After graduating from the University of Texas at Austin with a PhD in Social Psychology, his post-graduate work consisted of eight years of full-time statistical consulting, training, and documentation creation for researchers in a wide variety of academic disciplines. Dr. Neilands is conversant with multivariate statistical models with a special interest in structural equation modeling and confirmatory factor analysis of survey scale and behavioral sciences data. He has considerable experience with longitudinal data analysis methods such as growth curve analysis and multilevel (hierarchical linear) modeling. He maintains an active interest in advanced, likelihood-based methods for handling missing data in applied research settings, methods for handling non-normal outcome data in structural equation and mixed effects models, and influential case diagnostic methods in regression analysis.

Dr. Neilands serves as a resource to participants in the program by helping participants design quantitative studies, peer-reviewing their grant proposals and working to craft data analysis sections for proposals. He also assists program participants with sample size calculations, survey instrument development, hypothesis generation, and study design issues.

Click here for more information on Dr. Neilands.

Program Faculty Mentors

Emily Arnold, PhD, MPH

Associate Professor, Department of Medicine

Dr. Arnold’s research agenda is primarily devoted to reducing HIV-related health disparities for African American men who have sex with men, with a strong emphasis on community collaborative research designs and building HIV-prevention intervention programs. Dr. Arnold has a great deal of experience in conducting and teaching others to do qualitative and mixed methods research and she has worked with various research teams, as well as post-doctoral research fellows, international trainees, graduate students, medical students, and community members to implement these research designs. Building community collaborative partnerships has been an essential part of Dr. Arnold’s research agenda, from the point of forming community advisory boards to weigh in on data collection instruments to disseminating findings back to community members. Her current studies include testing an HIV-prevention intervention for African American men who have sex with men and women using a randomized controlled trial, building community and academic partnerships to alleviate HIV-related health disparities for African Americans, examining social support and social network-based forms of HIV prevention among African American LGBT youth, using mixed methods to examine HIV-related diffusion of innovations through social networks among African American MSM, and a policy-related study looking at the impact of health care reform on PLWHA and the agencies that serve them.

Click here for more information on Dr. Arnold.

Cherrie B. Boyer, PhD

Professor of Pediatrics, Division of Adolescent Medicine

Dr. Boyer is Director of Interdisciplinary Training in the UCSF Division of Adolescent Medicine. She is an internationally recognized health psychologist with over 20 years of research experience in the area of adolescent and young adult health. Dr. Boyer has been the recipient of many grant awards and has published widely in the area of sexually transmitted infections (STIs) and human immunodeficiency virus (HIV) prevention. Dr. Boyer’s program of research focuses on biopsychosocial antecedents of sexual risk behaviors and the role that these factors play in STIs, and their sequelae. She also has extensive research experience in the development and evaluation of cognitive-behavioral interventions to prevent and reduce the risk of STIs/HIV in adolescents and young adults in a variety of settings, including schools, teen and STD clinics, and community-based organizations in the San Francisco Bay Area as well as nationally and internationally with military personnel.

Dr. Boyer is currently principal investigator of a large multi-site randomized controlled cognitive-behavioral intervention trial to prevent and reduce risk for STIs, unintended pregnancies, alcohol and other substance misuse, and exposure to or involvement with sexual violence among military recruits and enlisted personnel. Dr. Boyer is a standing member of National Institutes of Health, Center for Scientific Review, Social Science and Population Studies study section and a member of UCSF’s Committee on Human Research.

Click here for more information on Dr. Boyer.

Mallory Johnson, PhD

Professor, Department of Medicine

MalloryDr. Johnson is a licensed clinical health psychologist whose research has focused on understanding, measuring, and improving the health of patients with chronic diseases such as HIV. His program of multidisciplinary collaborative research is focused on improving HIV treatment outcomes through patient empowerment. His teaching mission is primarily achieved through mentoring of early career investigators. He is the Co-Director of the NIH-funded Center for AIDS Prevention Studies (CAPS) and Director the the CAPS Developmental Core.

Click here for more information on Dr. Johnson.


James L. Sorensen, PhD

Professor In Residence, Department of Psychiatry

Dr. Sorensen began work in substance abuse treatment research more than twenty years ago, directing a National Institute on Drug Abuse (NIDA)-funded double-blind investigation of detoxification from heroin. He developed and evaluated a community network approach to drug abuse treatment, assessed family therapy’s efficacy with methadone maintenance patients, tested the efficacy of small-group HIV education with drug users, and evaluated the impact of case management for substance abusers with HIV/AIDS. Currently, he is investigating the utility of treating methadone maintenance patients in a therapeutic community. Dr. Sorensen also leads the California-Arizona Research Node of the NIDA Clinical Trials Network. This effort joins researchers and clinical treatment programs in conducting clinical trials of treatments.

Click here for more information on Dr. Sorensen.

Bill Woods, PhD

Professor, Department of Medicine

Dr. Woods has been at CAPS since 1987, and has played a significant role in the writing and submission of fourteen federally funded grants. His principal research interests are in three areas of HIV prevention: substance use and treatment, HIV counseling and testing, and sexual risk environments such as bathhouses. His recent work tends to combine these areas, looking primarily at the risk environment with a focus on the presence of drug use and the impact of HIV testing in these environments.

As a licensed psychologist with a part-time private practice serving gay men between 1988 and 1998, Dr. Woods frequently used that clinical experience to inform and shape the research projects with which he was involved. For example, his clinical work among gay men suggested the value of measuring the impact of protease inhibitor medications on sexual risk behaviors, resulting in a 1997 publication in New England Journal of Medicine, “Are advances in treatment changing views about high-risk sex?” Dr. Woods’ additional areas of research activity are health risk and prevention behavior of gay and bisexual men, environmental influences on behavior, and environmental and cognitive interventions in health promotion.

Click here for more information on Dr. Woods.