DUI / DWI Related Expert Witnesses

Dr. David H. Schaffer, MD, MRO, is Harvard-trained and dual-boarded in Medical Toxicology and Emergency Medicine, serving as the Chief of the Division of Medical Toxicology at Prisma Health–Upstate and faculty at the University of South Carolina School of Medicine in Greenville, SC. He is also a certified Medical Review Officer (MRO, MROCC).

Dr. Schaffer is regularly consulted for his expertise. Overall case retention is approximately 50/50 for plaintiff vs defendant. His services include medical record review, thorough reporting, deposition, and trial testimony as needed. Please feel free to call (828) 260-3742 or email david@schaffertox.com to walk through your case. No charge/bill time for this. Case highlights or referral available upon request.

Areas of Expertise:

Dr. Schaffer has published extensively in the fields of Medical Toxicology and Emergency Medicine. Outside of clinical practice and the occasional courtroom appearance, he has also consulted for major organizations—including SpaceX, Butterfly Network, and governmental entities—on a variety of clinical matters. Dr. Schaffer earned his medical degree from the University of North Carolina School of Medicine, completed his residency at Harvard, where he served as a Clinical Fellow at Harvard Medical School, and subsequently trained in Medical Toxicology at the University of Virginia.

Credential Highlights:

• Residency Training at Harvard and Massachusetts General/Brigham & Women's Hospitals
• Held appointment at Harvard Medical School as a Clinical Fellow
• Fellowship training at the University of Virginia
• Division Chief of Medical Toxicology at Prisma Health - Upstate, the only Medical Toxicology practice in the State of SC
• Faculty at USC School of Medicine in Greenville, SC and at Clemson University
• Attending Toxicologist for the Palmetto Poison Center in Columbia, SC
• Certified Medical Review Officer (DOT/HHS)
• Board-certified in both Emergency Medicine and Medical Toxicology

Sanjay Adhia, MD, MRO, is triple-Board-Certified in Psychiatry, Brain Injury Medicine, and Forensic Psychiatry. In addition to forensic/expert witness practice, Dr. Adhia treats patients with brain injuries, spinal cord injuries and recovery from stroke at renowned TIRR Memorial Hermann Hospital. 

His forensic practice focuses on the psychiatric factors and damages in cases of personal injury, medical malpractice, toxic exposure, testamentary capacity, undue influence and Dementia, TBI Brain injuries, competency, mental illness and complicating medical conditions.

Dr. Adhia treats and opines about Traumatic Brain Injury (TBI) in litigation as it can result in psychiatric or neurocognitive impairments. 

In all populations, he assesses PTSD, Anxiety, Depressive Disorders, risk of suicide, and malingering. 

Dr. Adhia is Associate Program Director for the Forensic Psychiatry Fellowship at University of Texas Health Science Center, McGovern School of Medicine where he is also an Assistant Professor of Psychiatry and Forensic Psychiatry mentor to residents.

Dr. Adhia volunteers with Physicians for Human Rights to assess victims of kidnapping and false imprisonment, human trafficking, undue influence, physical and sexual abuse, rape, and fear of imminent death. 

He conducts Independent Medical Examinations, review of records, and reports findings to courts and attorneys. He is available to testify in civil, criminal, probate, Federal, Immigration, military, and administrative jurisdictions.

Adhia & Associates also includes Kerry Mendes, MD—a Texas-based psychiatrist triple Board-Certified in General, Child & Adolescent, and Forensic Psychiatry—and Pia Quimson-Guevarra, DO, double Board-Certified in General and Forensic Psychiatry and licensed in Oregon and Washington. 

Drs. Mendes and Quimson-Guevarra also maintain active clinical practices alongside their forensic work: Dr. Mendes treats patients in Houston at Avenue360, and Dr. Quimson-Guevarra as director of Quimson Behavioral Health in Portland.

Sara J. Schreiber, PhD, D-ABFT-FT, is a worldwide leader and highly accomplished Forensic Toxicologist, Educator, and Consultant whose work has earned recognition at both the national and international levels through leadership, teaching, professional service, and participation in major forensic pursuits.

Dr. Schreiber has more than two decades of experience in forensic science, including over 25 years in Toxicology and Controlled Substance Analysis, and has served in senior laboratory, technical director, academic, and expert roles in governmental forensic institutions.

Litigation Support - Dr. Schreiber provides comprehensive technical review and expert analysis in complex criminal and civil matters where alcohol, drugs, and poisons are at issue. Her work bridges the gap between advanced toxicological data and the courtroom by critically evaluating laboratory methods, case files, bench notes, instrumental data, and reports to determine whether testing, interpretation, and quality practices meet accepted forensic and accreditation standards, including ISO/IEC 17025, American Board of Forensic Toxicology (ABFT), and relevant professional guidelines. 

Dr. Schreiber draws on her experience as a diplomate of the American Board of Forensic Toxicology and her leadership roles in organizations such as MAFS, SOFT, NAME, OSAC, and TIAFT. When requested, she provides clear, accessible expert testimony, affidavits, and consultation to attorneys, investigators, and courts, translating complex toxicological and medicolegal issues into opinions that can be understood and evaluated by judges and juries.

Areas of Expertise: 

Background Experience - Dr. Schreiber’s national notoriety is reflected in her repeated invitations to lecture, train, and present on forensic toxicology, opioid deaths, toxicology trends, medicolegal death investigation, expert testimony, and related forensic topics for professional associations, public defenders, prosecutors, medical and university audiences, public health groups, and scientific meetings across multiple states throughout the US. Her work has also contributed to public-health and death-investigation initiatives through overdose fatality review teams, national overdose fatality review consulting, Department of Justice (DOJ), National Institute of Justice (NIJ), and the RTI Center for Forensic Sciences technology Working Group participation, and overdose-related strategy teams.

Ryan Larrison is a senior forensic science and public sector executive with over 25 years of experience spanning Forensic Laboratory Operations, Quality Assurance, Firearms Examination, and large-scale Program and Systems Management within the Michigan Department of State Police.

Mr. Larrison currently serves in a senior leadership role within the Information Technology Division, where he directs a multi-million-dollar portfolio of enterprise systems, operations, and project delivery. In this capacity, he oversees complex, multi-agency initiatives, aligning technical execution with operational and investigative outcomes across multiple state departments. His work includes executive sponsorship of statewide technology programs and the coordination of vendors, stakeholders, and cross-functional leadership teams in high-risk, high-visibility implementations.

Litigation Support - Mr. Larrison serves as an expert witness in cases involving laboratory analysis or laboratory quality assurance. He has been deposed and/or testified over 200 times in the past 5 years.

Areas of Laboratory Expertise:

Background Experience - Prior to his current role, Mr. Larrison served as Assistant Division Director and Quality Assurance Manager for the Michigan State Police Forensic Science Division. In that role, he was responsible for the strategic direction, implementation, and oversight of quality systems across seven accredited forensic laboratories. He led all quality assurance activities, including training, corrective action programs, risk assessment frameworks, and accreditation compliance under ISO 17025 standards. His leadership resulted in a substantial reduction in non-conformities and sustained accreditation across all laboratory operations. 

Mr. Larrison has extensive experience as a program executive and project sponsor for complex forensic and evidential systems. He directed the statewide implementation of the Evidential Breath Alcohol Testing Program, including instrument selection, software integration, vendor coordination, and regulatory compliance, supported by a $2.5 million procurement process. He also led the development and implementation of a Forensic Genetic Genealogy program, establishing quality expectations, vendor deliverables, and investigative reporting standards.

A Special Education expert for five decades, Dr. Steven C. Imber served as a professor of special education from 1973-2021. He serves as a special education advocate, consultant to attorneys, parents and schools. He has conducted more than 600 independent educational evaluations.

Education:

• B.S. Psychology (High Honors) State University of New York at Buffalo
• Doctoral Studies, Clinical Psychology, University of Connecticut
• M.A. from the Department of Educational Psychology (Special Education - Learning Disabilities), University of Connecticut (Kappa Delta Phi)
• Ph.D. from the Department of Educational Psychology (Special Education -Emotional Disturbance (High Honors)

As a special education expert, Dr. Imber has worked on cases with children, adolescents and adults with a broad array of disabilities. He provides professional advocacy and consultation for children with the following disabilities:

• Autism Disorders
• Attention Deficit Disorders
• Emotional and Behavioral Disorders
• Emotional and Behavioral Disorders Intellectual Disabilities (Cognitive Deficits)
• Learning Disabilities
• Other Disabilities and Disorders

Areas of Expertise:

• Criminal Defense of Individuals with Disabilities – competence to stand trial and comprehension of Miranda Warning Rights
• Family Custody Matters involving Disputes regarding matters of Education and Special Education
• School Safety
• Special Education Regulations and Law
• Wrongful Death

Dr. Imber has been involved in cases from the following states: Alaska, Arizona, Connecticut, Delaware, Florida, Hawaii, Illinois, Massachusetts, Michigan, New Jersey, New York, Pennsylvania, Rhode Island, Tennessee, Utah, Vermont, Washington and West Virginia. 

Depositions and Direct Testimony
Dr. Imber has testified in federal court, various district courts, superior court, family and probate court and in numerous due process hearings since 1975.

Below are listed recent cases in which Dr. Imber provided testimony during depositions or directly in various court matters:

• October 21, 2021, Family Court: State of Hawaii, Plaintiff
• October 19, 2021, Hancock County Circuit Court, West Virginia Criminal Action, Defendant
• September 29, 2021, Chicago Public  Schools Cook County, Defendant
• July 6, 2021, Worcester County Probate and Family Court, Plaintiff
• August 10, 2021, Springfield District Court, Defendant
• May – June 2019, Commonwealth of Massachusetts, Division of Administrative Law Appeals, Bureau of Special Education Appeals BSEA, Plaintiff

Additional Accomplishments

• Published several articles in national and international journals within the fields of special education and psychology
• Presented at several local, state, regional, national and international conferences and meetings

Dr. Imber's CV is available upon request.