Drug-addiction and drug-dependency

Drug abuse is a complex phenomenon, and many factors (e.g., availability, cost) contribute to whether a particular drug will be abused by a particular individual. Nevertheless, many drugs that are abused have common neurobiological and behavioral effects. Consequently, some of the properties of drugs that contribute to abuse can be examined systematically in animals using well-established and validated behavioral procedures. A major strength of this area of research is that the effects of drugs in these procedures (i.e., in nonhuman species) are highly predictive of the effects of the same drugs in humans; thus, behavioral assessments are used both to study the underlying biological and behavioral phenomena associated with drug abuse (e.g., drug reinforcement, physical dependence) and to assess whether new chemical entities have properties in animals that would indicate a likelihood of abuse in humans. Preclinical abuse and dependence liability studies typically comprise the following approaches and procedures: Physical dependence Tolerance Drug discrimination Self-administration Conditioned place preference.