Table 5.

Suggested Approaches to the Assessment of Cannabis Exposure According to Population and Setting

Setting	Population	Recommendation
Clinical	Psychosis, engaged with treatment	Further research is required to investigate the validity of different self-report measures, particularly for patients with severe cognitive or psychosis symptoms Qualitative immunoassays may aid honest disclosure of recent drug use
Clinical	Psychosis, not engaged with treatment	Self-report measures should be interpreted with caution Quantitative biochemical tests
Clinical	Psychosis, high-risk/forensic	Qualitative immunoassay tests may be subject to tampering; quantitative biochemical tests (plasma>urine) are indicated
RCT	Psychosis with cannabis use disorder Cannabis use as a primary outcome	In depth self-report measures such as TLFB or ecological momentary assessment may be worthwhile Quantitative biochemical tests
RCT	Psychosis with cannabis use disorder Cannabis use as a secondary outcome	Concise self-report measures may be sufficient Quantitative biochemical tests
Epidemiological study	General population	Concise self-report measures alongside quantitative biochemical tests
Epidemiological study	Psychosis populations	Concise self-report measures alongside quantitative biochemical tests

RCT, randomised controlled trial.