verity based on the number of symptom criteria endorsed. As a general estimate of sever-
ity, a mild substance use disorder is suggested by the presence of two to three symptoms,
moderate  by four to five symptoms, and severe by six or more symptoms. Changing severity
across time is also reflected by reductions or increases in the fr equency and/or dose of
substance use, as assessed by the individual’s  own report, report of knowledgeable others,