Dependence and diagnosis

This chapter provides an overview of the nature of substance use disorders, the common diagnostic systems used to determine their presence, mechanisms leading to suspicion for the presence of a substance use disorder and referral to an addiction specialist, and diagnostic assessment. Substance dependence is defined similarly regardless of the specific substance involved. In general, dependence is the use of a substance or excessive thoughts about a substance assuming great importance to the detriment of other activities that had previously had greater importance. Thus, the critical distinction that must be made in order to classify an individual as having substance dependence is an overall negative impact of drug involvement on that individual's functioning. To allow for reliable identification of individuals with dependence, two main diagnostic systems have arisen.