Our research center offers professional and experienced staff including:

  • Board Certified Physicians
  • Licensed Psychologists
  • Adult Nurse Practitioners
  • Registered Nurses
  • Certified Clinical Research Coordinators
  • Certified Medical Assistants
  • Support Personnel

Ward T. Smith, MDWard T. Smith, MD, Director of Research/Principal Investigator

Ward T. Smith, MD, is the Director of Research at Summit Research Network, formerly Pacific Northwest Clinical Research Center, which he established in 1976. He has been the principal investigator in over 400 clinical trials evaluating treatments of disorders of the central nervous system. Dr. Smith is a graduate of Princeton University, BA, 1961, and the University of Pennsylvania Medical School, M.D., 1965. He completed two residencies, one in internal medicine at Providence Hospital, Portland, Oregon 1969-1972, and one in psychiatry at Oregon Health Sciences University 1972-1975. Dr. Smith was in the U.S. Army Medical Corps, Vietnam, 1966-1968.

loskScott Losk, PhD, Principal Investigator

Scott Losk, PhD, obtained a doctorate at Fuller Graduate School of Psychology in 1989, and did a post-doctoral fellowship in medical psychology at Oregon Health Sciences University. He has been in private practice since 1990, with an emphasis on clinical psychology, neuropsychology, and geriatric psychology. Dr. Losk joined Summit Research Network, formerly Pacific Northwest Clinical Research Center, also in 1990. He has been an investigator in over 100 clinical trials evaluating treatments of disorders of the central nervous system, and the principal investigator in over 75 clinical trials evaluating treatments for Alzheimer’s disease. Dr. Losk is active in the Alzheimer’s community providing talks and presentations to caregivers and other professionals.

MaryAnn ConradMaryAnn Conrad, MD, Principal Investigator

MaryAnn Conrad, MD, graduated from the University of Washington with a bachelor’s degree in psychology in 1987, and a medical degree in 1991. She is board certified in internal medicine and completed her internal medicine residency at the University of Hawaii in 1995. Before joining Summit Research Network in 2002, Dr. Conrad practiced as a primary care physician for Providence Medical Group and Kaiser Permanente. At Summit she enjoys focusing on clinical research, mental health and women’s health. When not taking care of patients at Summit, Dr. Conrad enjoys hanging out with her husband and cat, watching Blazer games, hiking, going to the Oregon coast, and photography.

James BergtholdJames Bergthold, MD, Principal Investigator

James Bergthold, MD, received a bachelor’s degree in biology in 1986 from Biola University and a medical degree from the Medical College of Wisconsin in 1992. Following his residency in internal medicine from Oregon Health Sciences University in 1995, he was a partner at HealthFirst Medical Group and the Providence Medical Group. Dr. Bergthold’s special interests include geriatric medicine, cardiology and diabetes. He has been with Summit Research since 2001.

Alan YeoAlan Yeo, MD, MPH, Principal Investigator

Alan Yeo, MD, MPH, graduated from Biola University with a Bachelor of Science degree in Biochemistry in 1994. He completed his medical and master of public health degrees from Oregon Health Sciences University in 2000. He is board certified in Psychiatry and Sleep Medicine and he joined Summit Research Network, Inc. in 2010. He has been an investigator in over 100 clinical trials involving major depressive disorder, bipolar disorder, generalized anxiety disorder, post-traumatic stress disorder, attention deficit hyperactivity disorder, Alzheimer’s disease, sleep disorders, fibromyalgia and migraine headache since 2006. Aside from conducting clinical trials, Dr. Yeo works as a staff psychiatrist at Portland State University, Center for Student Health and Counseling. In his spare time, he enjoys traveling and spending time outdoors. He loves spicy food.


Philip Bolton, MD, obtained a bachelor’s degree in Biology from Colgate University in 1987 and a medical degree from Albany Medical College in 1995. In 1999, he graduated from the Psychiatry Residence Training Program at Oregon Health Sciences University. Since 2004 he has been a Diplomate of the American Board of Psychiatry and Neurology. Dr. Bolton has provided inpatient psychiatric treatment at Providence St. Vincent Medical Center and outpatient psychiatric treatment in a variety of settings. Since 2014 he has been an investigator at Summit Research Network. Dr. Bolton has studied complimentary medicine including acupuncture and qigong. He enjoys spending time with his family hiking and exploring Oregon.

mary_hortonMary Horton, RN, ANP SUB-INVESTIGATOR/RATER

Mary Horton graduated from Walla Walla School of Nursing and the Nurse Practitioner program at Kaiser Permanente. She is Board Certified by the ANCC, the certifying organization for Nurse Practitioners. She joined Summit Research in 1998 and has participated in over 100 clinical trials involving depression, anxiety, bipolar disorders, dementia, alcohol dependence, migraine & fibromyalgia. Prior to coming to SRN, she worked at Kaiser Permanente in primary care.


Carrie Crider, BS, received her bachelors in Psychology at Portland State University. She has been a Research Clinician at Summit for over ten years. Carrie has clinical trial experience in studies focusing on depression, anxiety, bipolar disorder and Alzheimer’s disease. At Summit, Carrie has been a sub-investigator on over 60 studies. Prior to working at Summit, Carrie attended school at Queens College in New York and worked in a research and publishing capacity studying the effects of dementia on emotion under Dr. Joan Borod. Before this, Carrie worked at OHSU on a cognitive remediation program for children who were cancer survivors.