Finally, item-response theory (IRT, where “item” typically refers to a single question or criterion) is being increasingly applied to calibrate and assess the performance of individual drug use symptomatology34. As illustrated using item response curves (Fig. 4), IRT can determine where on the dimension of SUD risk (ranging from low to high) each diagnostic criterion provides information and how well items discriminate between those with high and low liability to SUD. Using this approach, it has been shown that using cocaine is associated with more detrimental and negative consequences, whereas the risk of experiencing such outcomes as a result of cannabis or hallucinogen use is considerably lower34.
