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

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