Table 1.

Cannabis use and psychotic experience questions from the UK Biobank Mental Health Questionnaire.

Categories of self-reported psychotic experiences
Auditory hallucinations	Did you ever hear things that other people said did not exist, like strange voices coming from inside your head talking to you or about you, or voices coming out of the air when there was no one around?
Visual hallucinations	Did you ever see something that wasn’t really there that other people could not see?
Persecutory delusions	Did you ever believe that there was an unjust plot going on to harm you or to have people follow you, and which your family and friends did not believe existed?
Delusions of reference	Did you ever believe that a strange force was trying to communicate directly with you by sending special signs or signals that you could understand but that no one else could understand (e.g., through the radio or television)?
Qualities of self-reported psychotic experiences
Age of onset	How old were you (approximately) when you first had one of these experiences?
Distress	How distressing did you find having any of these experiences?
Help-seeking	Did you ever talk to a doctor, counselor, psychiatrist, or other health professionals about any of these experiences?
Self-reported cannabis use
Cannabis ever-use	Have you taken cannabis (marijuana, grass, hash, ganja, blow, draw, skunk, weed, spliff, dope), even if it was a long time ago?
Cannabis use frequency	Considering when you were taking cannabis most regularly, how often did you take it?