Faculty & Fellows


Elisa Gumm, DO
Clinical Assistant Professor of Psychiatry
Addiction Medicine Fellowship Director
Susan Hadley, MD
Clinical Assistant Professor, Family and Community Medicine
Addiction Medicine Fellowship Co-Director
Shawn Platt, DO
Clinical Assistant Professor of Psychiatry
Addiction Medicine Fellowship Co-Director
Jasleen Chhatwal, MD 
Assistant Professor of Psychiatry
Brittany Pace, MD 
Clinical Assistant Professor
Stephen Remolina, MD
Clinical Assistant Professor

Current Fellows

Arun Chakrabarty, MD

Arun Chakrabarty, MD, was born in India and raised in southern California. He graduated from University of California, San Diego majoring in economics and minor in molecular biology. He graduated from Loma Linda University School of Medicine,  was subsequently engaged in several clinical trials as a research fellow and was briefly an ophthalmology resident. Arun completed his internal medicine residency at St. Mary Medical Center, a UCLA-affiliate program, in Long Beach, CA in 2014. He worked as a hospitalist at Desert Regional Medical Center in Palm Springs and subsequently at Antelope Valley in Lancaster, CA and Queen of the Valley in Napa, CA. Arun served as associate faculty professor for the family residency program for University of California program from 2016-2017. He also worked per diem at various other hospitals throughout California. He recently worked at an outpatient urgent care center in Hesperia, CA and most recently in correctional telemedicine based in Costa Mesa/Santa Ana region of CA prior to starting his current addiction fellowship at University of Arizona-Tucson. Arun is fluent in Bengali and understands Hindi and Spanish. He enjoys meteorology and mineralogy. He likes to travel and experience different cultures and cuisines.

Chris Dixon, DO

Chris was born and raised in Tucson, AZ. He graduated from the University of Arizona in 2001 with a Bachelor of Science in Psychology and subsequently received his Doctor of Osteopathic Medicine degree from Midwestern-AZCOM in Glendale, AZ in 2006. He completed his Family Medicine residency with Clarkson Family Medicine in Omaha, NE in 2009. From residency graduation in 2009 until starting addiction medicine fellowship training in 2021, he has worked as a family medicine physician at the El Rio Community Health Center in Tucson, providing outpatient primary care in the clinic setting as well as inpatient care for El Rio patients hospitalized at St. Mary’s Hospital. He loves working with medical students and served as a regional director of medical education for ATSU-SOMA from 2014-2021. Chris is fluent in Spanish and has traveled to Guatemala for medical mission trips with the DOCARE International organization in 2018, 2019, and 2020. Chris and his wife are the proud parents of five children. When not spending time with his family or seeing patients, Chris also enjoys basketball, golf, guitar, and reading. 

Alicia Hidalgo, MD

Alicia Hidalgo received her medical degree from the University of New Mexico in Albuquerque, NM where she was born and raised. Upon completion of medical school, she moved to Portland, OR to complete her residency in internal medicine. Following her residency, she served as chief resident and subsequently worked as a hospitalist where she discovered her interest in and passion for treatment of patients with substance use disorder. She then returned to the Southwest to continue her education at the University of Arizona Addiction Medicine fellowship. When not working, Alicia spends time with her family and enjoys a variety of outdoor activities, running, and traveling.

Lindsey Retterath, MD

A Midwestern native, Lindsey Retterath received her medical degree from Michigan State University College of Human Medicine in 2015, and then completed the combined Emergency Medicine and Pediatrics Residency Program at University of Arizona. She continues to works an Emergency Physician in Tucson and began as an Addiction Medicine Fellow in 2020. Her special interests include management of substance use disorders in the Emergency Department and Adolescent Addiction Medicine. Her undergraduate background is in Sociology and Spanish. Prior to going into medicine, she did work in the non-profit sector and has maintained an active interest in social determinants of health, public health, and health policy. She loves working with a variety of patient populations in Tucson. In her free time, you’ll likely find her on a hiking trail or climbing crag somewhere in Southern Arizona.

Spencer Roberts, DO

Bio coming soon!