The need to increase the diagnostic utility of a classification of cannabis use disorders is as important as the development of dimensional measures that discriminate across the entire spectrum of cannabis use disorder severity. The introduction of a cannabis use criterion to DSM-V will necessarily be different from a consumption criterion proposed for alcohol and other drug use disorders. This added complexity can be addressed by examining the psychometric properties of alternative frequency-only measures with various cutoff points for each drug use disorder. The most psychometrically sound frequency of use criterion for each drug can then be incorporated within the DSM-V diagnostic criteria with the caveat stated in the manual that clinical judgment is required to ensure that the quantity of use is sufficiently high among those who met the frequency threshold. This proposed DSM-V structure would not completely address the difficulty of determining the quality of cannabis (i.e., its THC level) or of other drugs used, with the exception of possibly alcohol.
