Table 1.
Examples of measures assessing cannabis-associated psychotic symptoms
| Observational studies | THC-challenge studies | Medicinal cannabis studies | |
|---|---|---|---|
| Design-specific definition of CAPS | Acute cannabis-associated psychotic experiences as retrospectively assessed using self-report measures in individuals using cannabis sampled from the general population | Degree of psychotic symptom change in response to THC, estimated from between-subject (placebo groups versus THC group) or within-subject (pre-THC versus post-THC assessment) comparisons in healthy participants | Adverse reactions involving psychosis resulting from the use of medicinal cannabis products containing THC |
| CAPS – psychosis(-like) | ‘After taking cannabis, have you had strange, unpleasant experiences such as hearing voices or becoming convinced that someone is trying to harm you, or that you are being persecuted?’78 | Changes in Brief Psychiatric Rating Scale following THC administration23 | Occurrence of any psychotic symptom when taking medicinal cannabis products79 |
| CAPS – hallucinations | ‘How often have you experienced the following reactions to cannabis use, while high or under the influence of cannabis? Auditory or visual hallucinations’80 | Changes in Positive and Negative Syndrome Scale (hallucinations) following THC administration25 | Adverse events (hallucinations) when taking medicinal cannabis products81 |
| CAPS – delusions | ‘How often have you experienced the following reactions [delusional] to cannabis use, while under the influence of the substance?’80 | Changes in Psychotomimetic States Inventory (delusion subscale) following THC administration82 | Adverse events (delusions) related to treatment with medicinal cannabis20 |
| CAPS – paranoia | ‘How often have you felt suspicious while smoking cannabis?’22 | Changes in Visual Analogue Scales (paranoia item) following THC administration83 | Frequency of adverse events during medicinal cannabis trial (paranoia)84 |
| CAPS – full episode | Emergency medical treatment due to the occurrence of psychotic symptoms following cannabis use15 | Acute cannabis-induced psychosis following the administration of oral cannabis85 | Occurrence of acute psychotic episode during the trial31 |