title: Psychophysiological evidence of altered neural synchronization in cannabis use: relationship to schizotypy.
abstract: OBJECTIVE
  Cannabis use may produce neurophysiological disturbances similar to those observed in schizophrenia, particularly in relation to altered neural synchronization. Therefore, the current experiment examined the effect of cannabis use on EEG neural synchronization using the auditory steady-state evoked potential.
  
  
  METHODS
  Auditory steady-state evoked potentials were assessed using varying rates of stimulation (auditory click-trains of 20, 30, 40 Hz) in current cannabis users (N=17) and drug-naive comparison subjects (N=16). EEG spectral power and signal-to-noise ratio at each stimulation frequency were compared between groups.
  
  
  RESULTS
  Cannabis users showed decreased EEG power and signal-to-noise ratio at the stimulation frequency of 20 Hz. In addition, current cannabis users demonstrated increased schizotypal personality characteristics as assessed with the Schizotypal Personality Questionnaire, which positively correlated with total years of cannabis use. Finally, within the cannabis group, 20-Hz power values were negatively correlated with Schizotypal Personality Questionnaire scores.
  
  
  CONCLUSIONS
  These data provide evidence for neural synchronization and early-stage sensory processing deficits in cannabis use. This finding, along with the observed increased rates of schizotypy in cannabis users, adds support for a cannabinoid link to schizophrenia spectrum disorders.
authors.affiliation: Department of Psychology, Indiana University, 1101 East 10th St., Bloomington, 47405, USA. pskosnik@indiana.edu
authors.forename: Patrick D
authors.initials: PD
authors.lastname: Skosnik
authors.forename: Giri P
authors.initials: GP
authors.lastname: Krishnan
authors.forename: Erin E
authors.initials: EE
authors.lastname: Aydt
authors.forename: Heidi A
authors.initials: HA
authors.lastname: Kuhlenshmidt
authors.forename: Brian F
authors.initials: BF
authors.lastname: O'Donnell
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology*; D015897:Comorbidity; D003344:Cortical Synchronization / Q000706:statistics & numerical data*; D004569:Electroencephalography / Q000706:statistics & numerical data; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology*; D011930:Reaction Time / Q000502:physiology; D012559:Schizophrenia / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D012565:Schizophrenic Psychology; D012569:Schizotypal Personality Disorder / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology*; D011795:Surveys and Questionnaires