About Dr. Van Sickle
Marcus R. Van Sickle, PhD, ABPP is board certified in Forensic Psychology and in Behavioral & Cognitive Psychology by the American Board of Professional Psychology (ABPP). His forensic practice includes competency to stand trial evaluations, criminal responsibility (sanity) evaluations, and a broad range of forensic assessments involving cognition, behavior, and risk.
In addition to his doctoral training, Dr. Van Sickle holds a postdoctoral Master of Science in Clinical Psychopharmacology (MSCP) and advanced medical-psychological training integrating pharmacology, neuroscience, and behavioral science into forensic analysis. He holds licensure as an Advanced Practice Medical Psychologist (MPAP) in jurisdictions where authorized by law, and practices within the scope of licensure as a psychologist with additional training in psychopharmacology in other jurisdictions.
Dr. Van Sickle routinely provides expert testimony and consultation in matters involving:
Alcohol, intoxication, and memory (including blackouts and fragmentary recall)
Victim behavior and counterintuitive responses to trauma
Sleep disorders, parasomnias, automatism, and altered states of consciousness
Violence risk, threat assessment, and behavioral risk formulation
He is also a Certified Threat Manager (CTM) through the Association of Threat Assessment Professionals and applies structured, evidence-based threat and risk assessment methodologies in both forensic and operational contexts.
Dr. Van Sickle is a retired military veteran and the Owner and Principal Consultant of Themis Forensic Psychological Services, LLC, providing services nationally in accordance with applicable licensure and jurisdictional requirements.
