The importance of choosing an appropriate rating scale can be shown by considering two hypothetical patients: the first is a working doctor who is severely dependent on opiates, and the second is a woman with a mild addiction to gambling.[1] An instrument that focuses narrowly on a history of drug abuse would find the man to have the more severe addiction of the two.[1] However, a more holistic instrument may find that, whilst the man’s dependence is severe, his relationships and work life is untroubled; on the other hand, the woman’s addiction may have led to drastic impairments in functioning, and would therefore be considered the more severe case.[1]
Reference:
[1] Samet S, Waxman R, Hatzenbuehler M, Hasin DS. Assessing addiction: concepts and instruments. Addict Sci Clin Pract 2007; 4 (1): 19–31.