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California School of Professional Psychology

Clinical Psychology


Fellow, Rockway Institute

Associate Professor

Alliant International University Los Angeles
1000 South Fremont Ave, unit #5
Alhambra CA 91803


Courses, Research Interests, Publications

Advanced Psychopathology; Clinical Interviewing I, II; Affirmative Substance Abuse Treatment (more broadly, Affirmative Addictions Treatment); LGBT Addictions Treatment (in person and online as part of the Rockway Certificate in LGBT Mental Health); LGBT Health Disparities (online; Rockway Certificate in LGBT Mental Health); Loss, Grief and Bereavement; Clinical Psychopharmacology

Intersection of substance abuse and HIV-related risk behaviors among gay and bisexual men (GBM); health disparities among LGBT persons; affirmative addictions treatment models; mental health issues among LGBT youth

Mona, L. R., Fraley, S., Theodore, P.S., Cameron, R. P., Ballan, M. S. (In press). Sexual expression and intimate relationships among lesbian, gay, and bisexual people with physical disabilities. In R. Fassinger and S. Morrow's (Eds.), Sex in the Margins: Erotic Lives of Lesbian, Gay, and Bisexual People. Washington DC: American Psychological Association.

Theodore, P.S. (2011). Sex, drugs and HIV: Clinical issues and assessment strategies. In C. Silverstein (Ed.), The Initial Psychotherapy Interview: A Gay Man Seeks Treatment (pp.175-202).New York: Elsevier. [also available in electronic form: Retreived from http://www.elsevierdirect.com/product.jsp?isbn=9780123851468] *Received the Division 44 2011 Distinguished Book Award

Theodore, P.S., Achiro, R.*,Durn, R., &Antoni, M.H. (2011). Body dissatisfaction and methamphetamine use among HIV-positive gay and bisexual men: A pilot study.Substance Use and Misuse, 46 (14), 1745-1749.doi:10.3109/10826084.2011.618998

Fraley, S., Mona, L., Theodore, P.S. (2007). The Sexual Lives of Lesbian, Gay, and Bisexual People with Disabilities: Psychological Perspectives. Sexuality Research and Social Policy: Journal of NSRC, 4 (1), 15-26.

Theodore, P.S., Durn, R., Antoni, M.H., Fernandez, M.I., Schneiderman, N. (2004). Intimacy and Sexual Behavior among HIV-Positive Men-Who-Have-Sex-With-Men in Primary Relationships. AIDS and Behavior, 8 (3), 321-331.

Theodore, P. S. &Basow, S. A. (2000). Heterosexual Masculinity and Homophobia: A Reaction to the Self. Journal of Homosexuality, 40, 31-48.

Theodore, P.S., Rahmani, C.R.*, Green, R.J., and Chiasson, J. (2013, August).Investigating LGBT-related bullying in a predominantly Latino sample of high school students. Paper presented at the American Psychological Association Convention, Honolulu, HI.

Sosa, E.* and Theodore, P. (2013, March).Sexual minority women and gynecological service utilization. Poster presented at the Society of Behavioral Medicine Conference, San Francisco, CA. [selected as a Meritorious Student Abstract and Elizabeth Sosa was recognized as the Outstanding Student Researcher by the Women's Health Special Interest Group (SIG)]

Magalhaes, C., Theodore, P., Magalhaes, E., Durn, R., and Katz, D. (2013, March). Healthcare service utilization in a sample of transgender women. Poster presented at the Society for Behavioral Medicine Conference, San Francisco, CA.

Theodore, P. S. (2012, August). Theories about and interventions to reduce LGBT bullying.Roundtable discussion on LGBT youth, children and families at the American Psychological Association Convention, Orlando, FL.

Magalhaes, C., Theodore, P., Durn, R., Magalhaes, E., and Katz, D. (2012, August).Exploring feminine gender in MTF transgender persons. Paper presented at the American Psychological Association Convention, Orlando, FL.

Theodore, P.S. (2011, August).Baseline findings from a study on the impact of an LGBT-inclusive curriculum on homonegativity and anti-LGBT bullying.In P.S. Theodore (Chair), Prevalence and reduction of bullying, victimization and suicide among LGBTQ youth.Symposium at the American Psychological Association Convention, Washington DC.

Theodore, P.S.(2011, October). Friends and Foes: LGBT Bullying. Paper presented at the 2011 Models of Pride Conference, Professional Track, Los Angeles, CA.

Rahmani, C.*and Theodore, P.S. (2011, September).Heterosexism and bullying: Consequences among and solutions for LGBTQ youth. Paper presented at the Institute for Violence, Abuse and Trauma Convention, San Diego, CA.

Magalhaes, C., Magalhaes, E., Duran, R., Theodore, P., and Katz, D. (2011, September).Exploring feminine identity from transgender women's perspectives. Paper presented at the Biennial International Symposium of the World Professional Association for Transgender Health, Atlanta, Georgia.

Theodore, P.S.&Magalhaes, C. (2010, October). LGBTQ Affirmative Substance Abuse Treatment.Workshop at the Los Angeles Gay and Lesbian Psychological Association Convention, Los Angeles, CA.

Theodore, P.S. (2010, April).Health disparities among gay and bisexual men. In P.S. Theodore (Chair), Beyond HIV: Health disparities among gay, lesbian, bisexual and transgender Communities. Symposium at the Society for Behavioral Medicine Conference, Seattle, WA.

Theodore, P.S., Durn, R.E., & Antoni, M.H. (2009, August). Body Image Dissatisfaction Explains Methamphetamine Use among HIV-Positive Gay Men. Poster presented at the American Psychological Association Convention, Toronto, Canada.

Magalhaes, E., Magalhaes, C.,Katz, D., Theodore, P.S., and Duran, R.(2009, June). Transgender femininity: An exploratory study. Poster presentation at the World Professional Association of Transgender Health (WPATH) Conference in Oslo, Norway.

Theodore, P.S., Durn, R.E., &Antoni, M.H. (2009, April). A Structural Model of Drug Use and Risky Sex among Gay and Bisexual Men who Attend Circuit Parties. Paper presented at the Society for Behavioral Medicine Conference, Montreal, Quebec, Canada.

Academic History and Background

B.S., Psychology, Honors, Lafayette College

PhD, University of Miami, 2005

Licensed Clinical Psychologist (PSY22511), California

Member, Society of Behavioral Medicine

Member, American Psychological Association (Divisions 38 and 44)

Professional Practice and Community Service

Advisor Board and Clinical Trainer for COLORS (Counseling Center providing free services for LGBTQ Youth); Consultant/Clinical Supervisor for AIDS Project Los Angeles (APLA); Ad hoc reviewer for Social and Personality Psychology Review

Psychologist for LGBT Bereavement Group, Senior Services, LA Gay and Lesbian Center and Leeza's Care/Olympia Medical Center

Bio and Links

Peter S. Theodore, PhD, is currently an associate professor with the Clinical Psychology PhD Program of the California School of Professional Psychology (CSPP) at Alliant International University, Los Angeles, the coordinator of the Clinical Health Emphasis Area for the PhD and PsyD Clinical Programs at CSPP, and a fellow of the university’s Rockway Institute (a center for LGBT psychological research and public policy). He is a licensed, practicing psychologist in the state of California whose expertise bridges the fields of HIV-prevention, LGBT affirmative therapy, substance abuse treatment and clinical health psychology. Drawing from cognitive-behavioral, strengths-focused, and existential theories, he has experience treating a myriad of mental health issues including depression, anxiety, substance abuse, trauma, sex and sexuality, and grief and bereavement. He earned his PhD from the University of Miami in Clinical Psychology in 2005 during which time he completed an NIMH pre-doctoral fellowship in HIV/AIDS clinical research and completed his full time APA-approved clinical internship at the Long Beach Veterans Healthcare System. He has directed a methamphetamine-abuse treatment program designed specifically for gay and bisexual men, and served numerous roles on multiple federally funded projects addressing the intersection of substance abuse and HIV-prevention. His current research addresses health disparities among LGBT persons, and reducing LGBT-related prejudice, discrimination, and violence. He has presented at numerous conferences and published in journals including AIDS and Behavior, Substance Use and Misuse, Journal of Homosexuality, and Sexuality Research and Social Policy: Journal of NSRC.