The two commonly used classification systems for data collection are the International Statistical Classification of Diseases and Related Health Problems, 10th revision, (ICD-10) and the Diagnostic and Statistical Manual of Mental Disorders, 5th edition, (DSM-5). Some of the terminology adapts poorly to the situation where prescription drugs are used to treat conditions, such as chronic non-malignant pain.
Tolerance is a decrease in response to a drug dose. It occurs with all chronically used drugs of dependence, including opioids and benzodiazepines. Increased doses are required to achieve the effects originally produced by lower doses.31
Dependence, in strict pharmacological terms, is a state that develops during chronic drug treatment in which drug cessation elicits an abstinence reaction (withdrawal).
Dependence can be associated associated with a whole range of psychoactive drugs or chemicals (eg caffeine, alcohol, opioid, cannabis or stimulant dependence). As awareness of problematic drug use grew, the definition of dependence changed to include addiction and abuse. Various definitions of dependence evolved with DSM-4, ICD-10, World Health Organization (WHO) and leading authors describing it as a cluster of behavioural, cognitive and physiological phenomena that may develop after repeated substance use. Now people link dependence with ‘addiction’ when in fact dependence can be a normal body response to a substance. While drug dependence can be part of addiction, is not the same thing.
To reduce confusion, the new DSM-5 (2013) criteria has replaced drug dependence with DSM-5 substance use disorder measured on a continuum from mild to severe. Refer to Appendix A.3 Misuse, non-medical use and abuse..
Note: There are legal implications involving the term dependence (eg restrictions around prescribing to drug-dependent persons). Characteristics of person who is drug dependent include having a history of substance misuse and being identified as a ‘doctor shopper’ or ‘prescription shopper’.202 Refer to Appendix A.4, Drug-seeking behaviour.
Substance use disorder has been introduced in DSM-540 to replace dependence (or dependence syndrome) as used to refer to complex symptoms beyond tolerance and withdrawal. The essential feature of SUD is a cluster of cognitive, behavioral and physiological symptoms indicating the individual continues using the substance despite significant substance-related problems.40 Diagnosis of SUD requires the presence of at least two of 11 criteria, across four categories: impaired control, social impairment, risky use and pharmacology.
Note: In DSM-5, substance dependence and substance abuse have been combined into a single category of SUDs (eg ‘benzodiazepines dependence’ would be included within sedative, hypnotic, or anxiolytic use disorder).40 Each SUD is divided into mild, moderate and severe subtypes, with the number of criteria present determining the severity. (Refer to Table 3 for DSM-5 criteria and Table A.1 for ICD-10 criteria.)
Withdrawal or withdrawal syndrome is a group of symptoms of variable clustering and degree of severity which occur on cessation or reduction of use of a psychoactive substance that has been taken repeatedly, usually for a prolonged period and/or in high doses. Signs of physiological disturbance may accompany the syndrome. A withdrawal syndrome is one of the indicators of a dependence syndrome.31
ICD-10 criteria for diagnosing benzodiazepine dependence*