Our Staff

As part of our mission to improve medical care, Oregon Center for Clinical Investigations, Inc. is dedicated to the management and timely completion of clinical research trials. Sponsors can rely on OCCI, Inc. to efficiently complete clinical trials in a competent and professional manner.

Our Investigators
Beal G. Essink, MD, D-ABPN
Principal Investigator
20 Years of Clinical/Research Experience

Beal G. Essink, MD received a bachelor’s degree in premedical sciences in 1994 and a medical degree in 1996, both from the University of Nebraska Medical Center. He completed a psychiatry residency at the Oregon Health and Science University, where he was chief resident from 1999 to 2000. Dr. Essink is currently the lead principal investigator for OCCI, Inc.’s Portland location, in addition to acting as principal investigator/sub-investigator at the Salem location of OCCI, Inc. Since 2003, Dr. Essink has been an investigator for over 200 central nervous system and internal medicine clinical trials. Dr. Essink is a diplomate of the American Board of Psychiatry and Neurology in psychiatry and sleep medicine.
 
Drissana T. Tran, MD-Internal Medicine
Principal Investigator/Sub-Investigator
24 Years of Clinical Experience

Drissana T. Tran, MD, obtained a bachelor’s degree in 1988 from the Robert D. Clark Honors College at the University of Oregon and a medical degree in 1992 from the Oregon Health Sciences University. She completed an internal medicine residency at Emanuel and Good Samaritan Hospitals in Portland, OR. In clinical practice since 1992, Dr. Tran has over 7 years of clinical research experience and has recently re-joined the OCCI, Inc. Salem location, where she is currently a clinical research investigator and rater for a variety of internal medicine and central nervous system studies. Dr. Tran is board-eligible in internal medicine.
 
Alexander E. Horwitz, MD, D-ABPN
Principal Investigator
32 Years of Clinical/Research Experience

Alexander E. Horwitz, MD received a bachelor’s degree from Sarah Lawrence College in 1980 and a medical degree from East Tennessee State University in 1984. He completed psychiatry residencies at the University of Tennessee’s Center for Health Sciences and the Cornell Medical Center in the New York Hospital. After having a private practice specializing in medical psychiatric services from 1988 to 1995, Dr. Horwitz was a unit psychiatrist and clinical director for the Forensic Hospital Developmental Disabilities Program at the Oregon State Hospital in Salem, OR from 1996 to 2013. Dr. Horwitz is currently the lead principal investigator for OCCI, Inc.’s Salem location, where he has been investigator for over 190 central nervous system and internal medicine clinical trials since 2000. Dr. Horwitz is a diplomate of the American Board of Psychiatry and Neurology in psychiatry and forensic psychiatry.
 

Our Clinical Research Staff

Each OCCI, Inc. site is supported by a staff of highly trained and experienced site directors, research coordinators and assistants, PSG technicians, and administrative personnel. All OCCI, Inc. staff are committed to providing quality patient care to our communities and successfully completing each of our clinical trials.