Table 1:

Definitions of Terms Related to Withdrawal Syndrome

Term	Definition
Tolerance	A decrease in response to a drug dose that occurs with continued use; increasing doses are required to achieve the effect originally produced by lower doses5
Physical dependence	A state of adaptation that manifests through a drug class–specific withdrawal syndrome5
Psychological dependence	A subjective sense of need for a specific psychoactive substance, either to obtain its positive effects or to avoid negative effects associated with abstinence5
Abstinence	Refraining from a drug whether as a matter of principle or for other reasons17
Abstinence syndrome	An older term for withdrawal syndrome17
Opioid-induced hyperalgesia	A state of nociceptive sensitization caused by exposure to opioids16