# 145 - Substance dependence # Substance dependence 463 Disorders due to substance use or addictive behaviours Boundary with other mental disorders and other medical conditions Numerous mental disorders and subthreshold symptoms may co-occur with episodic or continuous patterns of substance use. Similarly, continuous or episodic substance use increases the risk of mental disorders and other medical conditions. Co-occurring mental disorders and comorbid medical conditions should be diagnosed separately, along with a diagnosis of harmful pattern of psychoactive substance use. Substance dependence Available categories by substance class 6C40.2 Alcohol dependence 6C41.2 Cannabis dependence 6C42.2 Synthetic cannabinoid dependence 6C43.2 Opioid dependence 6C44.2 Sedative, hypnotic or anxiolytic dependence 6C45.2 Cocaine dependence 6C46.2 Stimulant dependence, including amfetamines, methamfetamine and methcathinone 6C47.2 Synthetic cathinone dependence 6C49.2 Hallucinogen dependence 6C4A.2 Nicotine dependence 6C4B.2 Volatile inhalant dependence 6C4C.2 MDMA or related drug dependence, including MDA 6C4D.2 Dissociative drug dependence, including ketamine and PCP 6C4E.2 Other specified psychoactive substance dependence 6C4F.2 Multiple specified psychoactive substance dependence 6C4G.2 Unknown or unspecified psychoactive substance dependence Essential (required) features • A pattern of recurrent episodic or continuous use of a psychoactive substance is required for diagnosis, with evidence of impaired regulation of use of that substance that is manifested in two or more of the following: • impaired control over substance use (i.e. onset, frequency, intensity, duration, termination, context); • increasing precedence of substance use over other aspects of life, including maintenance of health, and daily activities and responsibilities, such that substance use continues or escalates despite the occurrence of harm or negative consequences (e.g. repeated relationship disruption, occupational or scholastic consequences, negative impact on health); • physiological features indicative of neuroadaptation to the substance, including tolerance to the effects of the substance or a need to use increasing amounts of the substance to achieve the same effect; withdrawal symptoms following cessation or reduction in use of that substance; or repeated use of the substance or Diagnostic requirements for disorders due to substance use | Substance dependence Clinical Descriptions and Diagnostic Requirements for ICD-11 Mental, Behavioural or Neurodevelopmental Disorders pharmacologically similar substances to prevent or alleviate withdrawal symptoms (substance-specific features of withdrawal are described in Table 6.16, p. 484). Note: physiological features are only applicable for certain substances. • The features of dependence are usually evident over a period of at least 12 months, but the diagnosis may be made if use is continuous (daily or almost daily) for at least 3 months. Course specifiers for alcohol dependence For alcohol, a specifier is used to describe the pattern of substance use or remission. Unlike for other substances, a distinction is made between continuous and episodic use, as follows. Alcohol dependence, current use, continuous The individual exhibits alcohol dependence, with continuous consumption of alcohol (daily or almost daily) during at least the past month. Alcohol dependence, current use, episodic The individual exhibits alcohol dependence, with use during the past month and a history of intermittent heavy drinking, with periods of abstinence during the past 12 months. Alcohol dependence, early full remission After a diagnosis of alcohol dependence, and often following a treatment episode or other intervention (including self-help intervention), the individual has been abstinent from alcohol during a period lasting between 1 and 12 months. Alcohol dependence, sustained partial remission After a diagnosis of alcohol dependence, and often following a treatment episode or other intervention (including self-help intervention), there is a significant reduction in alcohol consumption for more than 12 months, such that even though intermittent or continuing drinking has occurred during this period, the definitional requirements for dependence have not been met. Alcohol dependence, sustained full remission After a diagnosis of alcohol dependence, and often following a treatment episode or other intervention (including self-intervention), the person has been abstinent from alcohol for 12 months or longer. 6C40.20 6C40.21 6C40.22 6C40.23 Diagnostic requirements for disorders due to substance use | Substance dependence 6C40.24 465 Disorders due to substance use or addictive behaviours Alcohol dependence, unspecified Course specifiers for substance dependence for substances other than alcohol For all psychoactive substance classes other than alcohol (see the list above and Table 6.13, p. 450), a specifier is used to further describe the pattern of substance use or remission in the context of substance dependence, using a fifth-character code. Unlike alcohol, separate codes for continuous and episodic current use are not provided. The x below corresponds to the fourth-character code indicating the substance class (1 for cannabis, 2 for synthetic cannabinoids and so on). Substance dependence, current use The individual exhibits current substance dependence, with episodic or continuous use of the substance within the past month. Substance dependence, early full remission After a diagnosis of substance dependence, and often following a treatment episode or other intervention (including self-help intervention), the individual has been abstinent from the substance during a period lasting between 1 and 12 months. Substance dependence, sustained partial remission After a diagnosis of substance dependence, and often following a treatment episode or other intervention (including self-help intervention), there is a significant reduction in substance use for more than 12 months, such that even though intermittent or continuous use has occurred during this period, the diagnostic requirements for dependence have not been met. Substance dependence, sustained full remission After a diagnosis of substance dependence, and often following a treatment episode or other intervention (including self-intervention), the person has been abstinent from the substance for 12 months or longer. Substance dependence, unspecified 6C40.2Z 6C4x.20 6C4x.21 6C4x.22 6C4x.23 6C4x.2Z Diagnostic requirements for disorders due to substance use | Substance dependence Clinical Descriptions and Diagnostic Requirements for ICD-11 Mental, Behavioural or Neurodevelopmental Disorders Additional clinical features for substance dependence • A subjective sensation of urge or craving to use the substance often, but not always, accompanies the essential features of substance dependence. • When present as an aspect of substance dependence, withdrawal symptoms must be consistent with the known withdrawal state for that substance (see Table 6.16, p. 484). Onset and course of withdrawal are time-limited, and are related to the type of substance and the dose used immediately before cessation or reduction in amount. • Tolerance varies as a function of individual factors (e.g. substance use history, genetics) and should be differentiated from initial levels of response during intoxication, which also exhibit significant individual variability. Laboratory testing that reveals high levels of the substance in bodily fluids with no evidence of significant symptoms of intoxication may be suggestive of tolerance. Tolerance to the effects of substances as indicated by different psychophysiological responses can develop at varying rates (e.g. tolerance to respiratory depression caused by opioid intoxication may develop prior to tolerance to the sedating effects of the drug). With abstinence, tolerance effects diminish over time. • Individuals with certain comorbid medical conditions (e.g. chronic liver disease) typically have reduced tolerance to substances. • Physical or mental health consequences (beyond the essential features of substance dependence) typically occur in people with substance dependence, but are not required for the diagnosis. Similarly, functional impairment in one or several domains of life (e.g. work, domestic responsibilities, child-rearing) is commonly seen in people with substance dependence, but is not required in order to assign the diagnosis. • Individuals with substance dependence have elevated rates of many other mental disorders, including conduct-dissocial disorder, attention deficit hyperactivity disorder, impulse control disorders, post-traumatic stress disorder, social anxiety disorder, generalized anxiety disorder, mood disorders, psychotic disorders and personality disorder with prominent dissocial features, as well as subthreshold symptoms. The specific pattern of co-occurrence depends on the substance involved, and reflects common risk factors and common causal pathways. These are distinguished from substance-induced mental disorders, in which the symptoms are a result of the direct physiological effects of the substance on the central nervous system. • A pattern of substance use that includes frequent or high dose administration occurs more often among certain subgroups (e.g. adolescents). In these cases, peer-group dynamics may contribute to the maintenance of substance use. Regardless of the social contributions to the behaviour, a pattern of substance use that is consistent with subgroup norms should not be considered as presumptive evidence of substance dependence unless all diagnostic requirements for the disorder are met. Diagnostic requirements for disorders due to substance use | Substance dependence 467 Disorders due to substance use or addictive behaviours Boundary with normality (threshold) • Frequent or even daily substance use of a substance does not automatically imply a diagnosis of substance dependence. There must also be evidence of the essential features of substance dependence, such as impaired control over use, increasing precedence of use over other life priorities or physiological features. • The presence of physiological features such as tolerance and withdrawal is sometimes referred to as “physiological dependence”. These features may occur, for example, in response to prolonged therapeutic use of certain medications, such as in patients who are appropriately prescribed opioid analgesics for cancer pain. By themselves, however, these features are not sufficient for a diagnosis of substance dependence, which also requires either impaired control over substance use or increasing precedence of substance use over other activities. Course features • The course of substance dependence varies by substance, frequency, intensity and duration of use. The central features of the dependence syndrome may be overshadowed by the harms to physical and mental health that patients with dependence often experience, and for which they frequently seek treatment. Numerous medical conditions can occur due to substance use in the course of substance dependence. These conditions tend to be specific for each substance, although some are shared across substances. Negative consequences to physical health reflect the known pharmacological effects of the relevant substance, the toxic effects of the substance on tissues and organs, or the route of administration (e.g. intravenous self-administration). Examples include alcoholic cirrhosis, infective endocarditis and HIV/AIDS. Medical conditions caused by substance use should be diagnosed separately. Developmental presentations • Substance dependence may develop more rapidly during adolescence than is usual during adulthood, especially when there are familial or other risk factors for substance dependence. • Tolerance to psychoactive substances may develop rapidly in adolescents and young adults, and may decline equally rapidly when substance use ceases or is reduced in quantity or frequency. • Withdrawal symptoms are well recognized in neonates born to women with substance dependence who have used psychoactive substances during pregnancy. However, the presence of a withdrawal state in a neonate should not be the sole basis for a diagnosis of substance dependence in the mother. • Older adults often have reduced tolerance to substances. Diagnostic requirements for disorders due to substance use | Substance dependence Clinical Descriptions and Diagnostic Requirements for ICD-11 Mental, Behavioural or Neurodevelopmental Disorders Sex- and/or gender-related features • Substance dependence has similar features in men and women, although the intensity of substance use and duration of use necessary to result in dependence may differ by sex. For example, alcohol dependence may occur after a lower cumulative alcohol intake in women compared to men because of sex-related differences in body mass and composition. • Women are less likely to be involved with the legal system in relation to substance use, and therefore may be less likely to come to clinical attention than men. In clinical contexts, women may be reluctant to admit using substances due to prevailing social attitudes and proscriptions. • In some societies it may be culturally unacceptable for women to admit to substance use. Specific probing may be necessary to elicit a history of substance use and dependence. Boundaries with other disorders and conditions (differential diagnosis) Boundary with substance intoxication Episodic or continuous intoxication with substances is a typical feature of substance dependence, but is not an essential feature. Conversely, even if frequent and severe, substance intoxication alone is not a basis for a diagnosis of substance dependence. If all diagnostic requirements of both conditions are met for the same episode of care, substance dependence should be assigned as the primary diagnosis, with an associated diagnosis of substance intoxication (e.g. opioid dependence with opioid intoxication) if appropriate to the specific clinical situation (e.g. in emergency settings). Boundary with harmful substance use Substance dependence is often associated with physical and mental health consequences, such as those seen in harmful pattern of psychoactive substance use. In the absence of the essential features of substance dependence, a diagnosis of harmful substance use can be given when there has been demonstrable harm to the individual’s physical or mental health or the health of others. Harmful pattern of psychoactive substance use and substance dependence should not be diagnosed together. Boundary with substance withdrawal Depending on the substance, many individuals with substance dependence develop substance withdrawal upon cessation or reduction in the amount of a substance consumed. In such cases, both substance dependence and substance withdrawal should be diagnosed. However, substance withdrawal can be diagnosed in the absence of a diagnosis of substance dependence – for example, in response to cessation of medically appropriate treatment with opioid analgesics that is not accompanied by the other essential features of substance dependence. Note: substance withdrawal is only applicable for some substances or substance classes (see Table 6.13, p. 450). Boundary with substance-induced mental disorders The impact of repeated or continuous use of substances characteristic of substance dependence may include substance-induced mental disorders, in which case both substance dependence and the relevant substance-induced mental disorder should be diagnosed (e.g. alcohol dependence with alcohol-induced delirium). Note: specific substance-induced mental disorders are only applicable for some substance classes (see Table 6.14, p. 454). Diagnostic requirements for disorders due to substance use | Substance dependence