Although opioids are commonly prescribed for pain, their addictive properties also make them liable for abuse. Opioid dependence and addiction are interchangeable terms, however the Diagnostic and Statistical Manual of Mental Disorders version IV (DSM IV) has adopted ‘dependence’ as the official term. Currently, the DSM IV is being revised to differentiate between the two aspects of substance dependence: the physiological changes in the brain that confer tolerance and the drug-seeking behaviors. The inter-national review committee has proposed the non-pejorative, unambiguous term ‘substance use disorder’ to describe dependence behaviour and the associated neurobiological changes [20]. Throughout this paper, the terms ‘opioid dependence’ and ‘substance use disorders’ will be used to refer to dependence as defined by the DSM IV criteria.
