title: The psychotomimetic states inventory (PSI): measuring psychotic-type experiences from ketamine and cannabis.
abstract: BACKGROUND
  This study reports a new measure of psychotomimetic states in the context of cannabis and ketamine use. The Psychotomimetic States Inventory (PSI) has sub-scales of Delusory Thinking, Perceptual Distortions, Cognitive Disorganization, Anhedonia, Mania and Paranoia.
  
  
  METHODS
  The PSI was administered in two independent group, repeated measures designs: an experimental study of ketamine and a naturalistic study of cannabis.
  
  
  RESULTS
  Both cannabis and ketamine produced reliable increases in ratings of psychotomimetic state effects across several sub-scales.
  
  
  CONCLUSIONS
  The PSI is a potentially useful measure of the nature and extent of the phenomenological effects of psychotropic drugs in schizophrenia-related research.
authors.affiliation: Sub-Department of Clinical Health Psychology, University College London, Gower Street, London WC1E 6BT, United Kingdom. o.mason@ucl.ac.uk
authors.forename: Oliver J
authors.initials: OJ
authors.lastname: Mason
authors.forename: Celia J M
authors.initials: CJ
authors.lastname: Morgan
authors.forename: Ana
authors.initials: A
authors.lastname: Stefanovic
authors.forename: H Valerie
authors.initials: HV
authors.lastname: Curran
mesh_terms: D000293:Adolescent; D000328:Adult; D000342:Affective Symptoms / Q000139:chemically induced / Q000523:psychology; D000778:Anesthetics, Dissociative / Q000633:toxicity*; D001714:Bipolar Disorder / Q000139:chemically induced / Q000523:psychology; D003072:Cognition Disorders / Q000139:chemically induced / Q000523:psychology; D003702:Delusions / Q000139:chemically induced / Q000523:psychology; D013759:Dronabinol / Q000633:toxicity*; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D007649:Ketamine / Q000633:toxicity*; D002189:Marijuana Abuse / Q000523:psychology*; D010259:Paranoid Disorders / Q000139:chemically induced / Q000523:psychology; D010469:Perceptual Distortion / Q000187:drug effects; D010555:Personality Inventory / Q000706:statistics & numerical data*; D011605:Psychoses, Substance-Induced / Q000523:psychology*; D015813:Substance Abuse Detection; D019966:Substance-Related Disorders / Q000523:psychology*
chemical_list: D000778:Anesthetics, Dissociative; D007649:Ketamine; D013759:Dronabinol