Last updated on: 11/15/2011 | Author:

Patrik Roser, PhD, MD Biography

Professor of Psychiatry at Ruhr-University Bochum (Germany)
Con to the question "Should Marijuana Be a Medical Option?"

“Reduced amplitudes of auditory evoked P300 are a robust finding in schizophrenic patients, indicating deficient attentional resource allocation and active working memory. Delta9-Tetrahydrocannabinol (Delta9-THC), the main active constituent of Cannabis sativa, has been known to acutely impair cognitive abilities in several domains, particularly in memory and attention. Given the psychotic-like effects of Delta9-THC, a cannabinoid hypothesis of schizophrenia has been proposed. This prospective, double-blind, placebo-controlled cross-over study investigated the acute effects of cannabinoids on P300 amplitude in 20 healthy volunteers (age 28.2+/-3.1 years, 10 male) by comparing Delta9-THC and standardized cannabis extract containing Delta9-THC and cannabidiol (CBD)… CBD has been known to abolish many of the psychotropic effects of Delta9-THC, but, unexpectedly, failed to demonstrate a reversal of Delta9-THC-induced P300 reduction… These data suggest that Delta(9)-THC may lead to acute impairment of attentional functioning and working memory.”

“Effects of Acute Oral Delta9-tetrahydrocannabinol and Standardized Cannabis Extract on the Auditory P300 Event-related Potential in Healthy Volunteers,” European Neuropsychopharmacology, Aug. 2008

Theoretical Expertise Ranking:
     Key Experts
Physicians [Physicians are the "key experts" in the medical marijuana debate because the issue is thought by many to be ultimately based on the medical value and risks of marijuana, and Physicians, with their training and clinical work, should (at least in theory) have the best knowledge of marijuana's medical value and risks.] [Note: Key Experts definition varies by sites that have this designation.]
Involvement and Affiliations:
  • Professor, Department of Psychiatry, LWL University Hospital, Ruhr-University Bochum (Germany)
  • Professor, Department of Psychiatry and Psychotherapy, Charit√© University Hospital Berlin (Germany)
  • Research Group, Clinical and Experimental Psychopathology, Department of General and Social Psychiatry, Psychiatric University Hospital Zurich (Switzerland)
  • PhD, school and date unknown
  • MD, school and date unknown
  • None found