Disorders due to use of hallucinogens

Description

Disorders due to use of hallucinogens are characterised by the pattern and consequences of hallucinogen use. Several thousand compounds have hallucinogenic properties, many of which are found in plants (e.g., mescaline) and fungi (e.g., psilocybin) or are chemically synthesized (e.g., lysergic acid diethylamide [LSD]). These compounds have primarily hallucinogenic properties, but some may also be stimulants. Much of the morbidity associated with these compounds arises from the acute effects related to Hallucinogen Intoxication. Hallucinogen Dependence is rare and Hallucinogen Withdrawal is not described. Among the mental disorders related to hallucinogen use, Hallucinogen-Induced Psychotic Disorder is the most frequently seen, although worldwide it is still fairly uncommon. [1]

Diagnostic requirements

WHO clinical descriptions and diagnostic requirements [1,2].

Subcategories

• 6C49.0 Episode of harmful use of hallucinogens

  An episode of hallucinogen use that has caused damage to a person’s physical or mental health or has resulted in behaviour leading to harm to the health of others. Harm to health of the individual occurs due to one or more of the following: (1) behaviour related to intoxication; (2) direct or secondary toxic effects on body organs and systems; or (3) a harmful route of administration. Harm to health of others includes any form of physical harm, including trauma, or mental disorder that is directly attributable to behaviour due to hallucinogen intoxication on the part of the person to whom the diagnosis of single episode of harmful use applies. This diagnosis should not be made if the harm is attributed to a known pattern of hallucinogen use. [1]

  Essential (Required) Features:

  • An episode of use of hallucinogens that has caused clinically significant damage to a person’s physical health or mental health (e.g., Hallucinogen-Induced Mood Disorder), or has resulted in behaviour leading to harm to the health of others.
  • Harm to health of the individual occurs due to one or more of the following: (1) behaviour related to intoxication; (2) direct or secondary toxic effects on body organs and systems; or (3) a harmful route of administration.
  • Harm to health of others includes any form of physical harm, including trauma, or mental disorder that is directly attributable to behaviour due to Hallucinogen Intoxication on the part of the person to whom the diagnosis of Episode of Harmful Use of Hallucinogens applies.
  • Harm to health is not better accounted for by another medical condition or another mental disorder, including another Disorder Due to Substance Use (e.g., Substance Withdrawal).

  Note: Harm to the health of the person to whom the diagnosis applies includes injuries caused by behaviour related to intoxication (e.g., impulsive aggressive behaviour, psychomotor impairment leading to injury), acute health problems resulting from substance use (e.g., overdose, acute gastritis, the effects of hypoxia or prolonged hyperactivity or inactivity), and exacerbation or decompensation of pre-existing chronic health problems (e.g., hypertension, liver disease, or peptic ulceration). Harm may also result from a harmful route of administration (e.g., injecting drug use causing blood-borne virus infections, cocaine use causing a perforated nasal septum). The relevant diagnostic codes from other chapters of the ICD-11, including the chapter on Injury, Poisoning or Certain Other Consequences of External Causes, should be used to describe the specific health consequences of the harmful substance use.

  Harm to the health of others includes any form of physical harm, including trauma (e.g., impaired driving causing a motor vehicle accident, assaultive behaviour leading to bodily harm to another person) or mental disorder (e.g., Post-Traumatic Stress Disorder arising from an assault by the intoxicated individual) that is directly attributable to behaviour due to substance intoxication on the part of the person to whom the diagnosis of Episode of Harmful Psychoactive Substance Use applies.

  Additional Clinical Features:

  • There must be explicit evidence of harm to the individual’s physical or mental health, or of substance-related behaviour due to intoxication that has led to harm to the physical or mental health of others. There must also be a clear causal relationship between the harm to health and the episode of hallucinogen use in question.
  • The likelihood of harm to self or others due behaviour related to intoxication varies substantially by substance. For example, such behaviour is unlikely to arise from caffeine or nicotine intoxication.
  • Hallucinogen use commonly occurs in the context of other mental disorders. An additional diagnosis of Episode of Harmful Use of Hallucinogens can be made if the index episode of hallucinogen use has resulted in clinically significant harm to the individual’s physical health or has exacerbated or triggered an episode of a pre-existing mental disorder (e.g., a Manic or Depressive Episode or a psychotic episode).
  • A diagnosis of Episode of Harmful Use of Hallucinogens often signals an opportunity for intervention, typically a low intensity intervention that can be implemented in a wide range of settings that is specifically aimed at reducing the likelihood of additional harmful episodes or of progression to Harmful Pattern of Use or Hallucinogen Dependence.
  • As more information becomes available indicating that the episode is part of a continuous or recurrent pattern of hallucinogen use, or if additional harmful episodes occur, a diagnosis of Episode of Harmful Use of Hallucinogens should be changed to Harmful Pattern of Use of Hallucinogens or Hallucinogen Dependence, as appropriate.

  Boundary with Normality (Threshold):

  • The diagnosis of Episode of Harmful Use of Hallucinogens requires clinically significant harm to the individual’s physical or mental health or that of others. Examples of impact on physical or mental health that would not be considered clinically significant include mild hangover, brief episodes of vomiting, or transient depressed mood.
  • A range of social problems may be associated with an episode of substance use that are not sufficiently severe to constitute clinically significant harm to physical or mental health (e.g., missed appointments, arguments with loved ones). Such problems are not a sufficient basis for a diagnosis of Episode of Harmful Use of Hallucinogens.

  Boundaries with Other Disorders and Conditions (Differential Diagnosis):

  • Boundary with Hazardous Substance Use: Hazardous Substance Use is classified in the chapter on ‘Factors Influencing Health Status or Contact with Health Services’ in the ICD-11 and not in the chapter on Mental, Behavioural, and Neurodevelopmental Disorders. Hazardous Substance Use appreciably increases the risk of harmful physical or mental health consequences to the user or to others to an extent that warrants attention and advice from health professionals, but has not resulted in specific identifiable harm and therefore does not meet the diagnostic requirements for Episode of Harmful Use of Hallucinogens.
  • Boundary with Harmful Pattern of Use of Hallucinogens: If the harm to health is a result of a known episodic or continuous pattern of substance use and all other diagnostic requirements are met, a diagnosis of Harmful Pattern of Use of Hallucinogens should be assigned. Substance use is generally considered to be following a pattern if there has been at least episodic or intermittent use over a period of at least 12 months. If harm is caused by use of hallucinogens but no information is available about the pattern or history of substance use, a diagnosis of Episode of Harmful Use of Hallucinogens may be assigned until such time as evidence for a pattern of use is ascertained.
  • Boundary with Hallucinogen Dependence: In Hallucinogen Dependence, individuals use hallucinogens persistently despite harm and adverse consequences. Harm caused by such use may be similar to that observed in Episode of Harmful Use of Hallucinogens. However, Hallucinogen Dependence also includes additional features of impaired ability to control use and increasing priority given to the substance use over other activities. Physiological features (e.g., tolerance) may also be present. If all diagnostic requirements for Hallucinogen Dependence are met, Episode of Harmful Use of Hallucinogens should not be assigned.
  • Boundary with Hallucinogen Intoxication: Hallucinogen Intoxication is defined by hallucinogen use that results in clinically significant transient hallucinogen-specific symptoms. Recovery from Hallucinogen Intoxication is generally complete and without physical or mental sequelae. If there is continuing damage or harm (e.g., the effects of hypoxia, the effects of prolonged hyperactivity or inactivity, tissue damage) due to an episode of Hallucinogen Intoxication, a diagnosis of Episode of Harmful Use of Hallucinogens may be assigned. If relevant at the time of the clinical encounter (e.g., in emergency settings), Episode of Harmful Use of Hallucinogens may be diagnosed with an associated diagnosis of Hallucinogen Intoxication.
  • Boundary with Hallucinogen-Induced Mental Disorders: Hallucinogen-Induced Mental Disorders can be associated with a single episode of hallucinogen use. If a Hallucinogen-Induced Mental Disorder has occurred as a form of harm resulting from a single episode of hallucinogen use, both Episode of Harmful Use of Hallucinogens and the relevant Hallucinogen-Induced Mental Disorder should be diagnosed (e.g., Episode of Harmful Hallucinogen Use with Hallucinogen-Induced Psychotic Disorder).
  • Boundary with overdose: When ingestion of psychoactive substances results in symptoms of overdose (e.g., coma; life-threatening cardiac or respiratory suppression), a diagnosis from the grouping of Harmful Effects of Substances in the chapter on Injury, Poisoning or Certain Other Consequences of External Causes should also be assigned.
• 6C49.1 Harmful pattern of use of hallucinogens

  A pattern of use of hallucinogens that has caused damage to a person’s physical or mental health or has resulted in behaviour leading to harm to the health of others. The pattern of hallucinogen use is evident over a period of at least 12 months if substance use is episodic or at least one month if use is continuous (i.e., daily or almost daily). Harm to health of the individual occurs due to one or more of the following: (1) behaviour related to intoxication; (2) direct or secondary toxic effects on body organs and systems; or (3) a harmful route of administration. Harm to health of others includes any form of physical harm, including trauma, or mental disorder that is directly attributable to behaviour related to hallucinogen intoxication on the part of the person to whom the diagnosis of Harmful pattern of use of hallucinogens applies. [1]

  Essential (Required) Features:

  • A pattern of continuous, recurrent, or sporadic use of hallucinogens that has caused clinically significant damage to a person’s physical health or mental health (e.g., Hallucinogens-Induced Mood Disorder), or has resulted in behaviour leading to harm to the health of others.
  • Harm to health of the individual occurs due to one or more of the following: (1) behaviour related to intoxication; (2) direct or secondary toxic effects on body organs and systems; or (3) a harmful route of administration.
  • Harm to health of others includes any form of physical harm, including trauma, or mental disorder that is directly attributable to behaviour related to substance intoxication on the part of the person to whom the diagnosis of Harmful Pattern of Use of Hallucinogens applies.
  • The pattern of hallucinogen use is evident over a period of at least 12 months if hallucinogen use is episodic or at least 1 month if use is continuous.
  • Harm to health is not better accounted for by another medical condition or another mental disorder, including another Disorder Due to Substance Use (e.g., Substance Withdrawal).

  Note: Harm to the health of the person to whom the diagnosis applies includes injuries caused by behaviour related to intoxication (e.g., impulsive aggressive behaviour, psychomotor impairment leading to injury; acute health problems resulting from substance use (e.g., overdose, acute gastritis, the effects of hypoxia or prolonged hyperactivity or inactivity), and exacerbation or decompensation of pre-existing chronic health problems (e.g., hypertension, liver disease, or peptic ulceration). Harm may also result from a harmful route of administration (e.g., injecting drug use causing blood-borne virus infections, cocaine use causing a perforated nasal septum). The relevant diagnostic codes from other chapters of the ICD-11, including the chapter on Injury, Poisoning or Certain Other Consequences of External Causes, should be used to describe the specific health consequences of the harmful substance use.

  Harm to the health of others includes any form of physical harm, including trauma (e.g., impaired driving causing a motor vehicle accident, assaultive behaviour leading to bodily harm to another person) or mental disorder (e.g., Post-Traumatic Stress Disorder arising from an assault by the intoxicated individual) that is directly attributable to behaviour due to substance intoxication on the part of the person to whom the diagnosis of Harmful Pattern of Psychoactive Substance Use applies.

  Course Specifiers:

  A specifier is used to further describe the harmful pattern of substance use, using a fifth-digit code. The fourth-digit code indicates the substance class (i.e., 9 for hallucinogens).

  6C49.10 Harmful Pattern of Use of Hallucinogens, episodic

  This category is assigned when all the diagnostic requirements for Harmful Pattern of Use of Hallucinogens are met and there is evidence of a pattern of recurrent episodic or intermittent use of hallucinogens over a period of at least 12 months that has caused clinically significant harm to a person’s physical or mental health or has resulted in behaviour leading to harm to the health of others.

  6C49.11 Harmful Pattern of Use of Hallucinogens, continuous

  This category is assigned when all the diagnostic requirements for Harmful Pattern of Use of Hallucinogens are met and there is evidence of a pattern of continuous hallucinogen use (daily or almost daily) over a period of at least 1 month that has caused clinically significant harm to a person’s physical or mental health or has resulted in behaviour leading to harm to the health of others.

  6C49.1Z Harmful Pattern of Use of Hallucinogens, unspecified

  Additional Clinical Features:

  • There must be explicit evidence of harm to the individual’s physical or mental health, or of related behaviour due to Hallucinogen Intoxication that has led to harm to the physical or mental health of others. There must also be a clear causal relationship between the harm to health and the episodic or continuous use of hallucinogens.
  • The likelihood of harm to self or others due behaviour related to intoxication varies substantially by substance. For example, such behaviour is unlikely to arise from caffeine or nicotine intoxication.
  • As more information becomes available about symptoms and behaviours related to the pattern of hallucinogen use as well as physiological features indicative of neuroadaptation to the substance, the diagnosis may be changed to Hallucinogen Dependence if diagnostic requirements are met.

  Boundary with Normality (Threshold):

  • The diagnosis of Harmful Pattern of Use of Hallucinogens requires clinically significant harm to the individual’s physical or mental health or that of others. Examples of impact on physical or mental health that would not be considered clinically significant include mild hangovers, brief episodes of vomiting, or transient depressed mood.
  • A pattern of hallucinogen use may cause a range of problems in functioning (e.g., missed appointments, arguments with loved ones) that are not sufficiently severe to constitute clinically significant harm to physical or mental health. Such problems are not a sufficient basis for a diagnosis of Harmful Pattern of Use of Hallucinogens.

  Developmental Presentations:

  • Harmful Pattern of Use of Hallucinogens is often a characteristic of late adolescence and young adulthood, and injuries and the consequences of aggressive behaviour are particularly common in this age group.
  • Harmful Pattern of Use of Hallucinogens in older adults may cause injuries and fractures due to the combination of lowered tolerance, psychomotor impairment induced by a substance, and disorders associated with ageing such as osteoporosis and Dementia.

  Sex- and/or Gender-Related Features:

  • The prevalence of Harmful Pattern of Use of Hallucinogens is higher in males than females, but the gender differential is smaller in countries where women play a greater role in the workforce. Gender differences in injuries and other forms of harm due to substance use are recognized.

  Boundaries with Other Disorders and Conditions (Differential Diagnosis):

  • Boundary with Hazardous Use of Hallucinogens: Hazardous Use of Hallucinogens is classified in the chapter on ‘Factors Influencing Health Status or Contact with Health Services’ in the ICD-11 and not in the chapter on Mental, Behavioural, and Neurodevelopmental Disorders. Hazardous Use of Hallucinogens appreciably increases the risk of harmful physical or mental health consequences to the user or to others to an extent that warrants attention and advice from health professionals, but has not resulted in specific identifiable harm and therefore does not meet the diagnostic requirements for Harmful Pattern of Use of Hallucinogens.
  • Boundary with Episode of Harmful Use of Hallucinogens: If the harm to health is a result of a single episode of use rather than a pattern of substance use, whether episodic or continuous, a diagnosis of Episode of Harmful Use of Hallucinogens should be assigned. Hallucinogen use is generally considered to be following a pattern if there has been at least episodic or intermittent use over a period of at least 12 months. If harm is caused by use of hallucinogens but no information is available about the pattern or history of hallucinogen use, a diagnosis of Episode of Harmful Use of Hallucinogens may be assigned until such time as evidence for a pattern of use is ascertained.
  • Boundary with Hallucinogen Dependence: In Hallucinogen Dependence, individuals use hallucinogens persistently despite harm and adverse consequences. Harm caused by such use may be similar to that observed in Harmful Pattern of Use of Hallucinogens. However, Hallucinogen Dependence also includes additional features of impaired ability to control use and increasing priority given to the substance use over other activities. Physiological features (e.g., tolerance) may also be present. If all diagnostic requirements for Hallucinogen Dependence are met, Harmful Pattern of Use of Hallucinogens should not be assigned.
  • Boundary with Hallucinogen Intoxication: Hallucinogen Intoxication is defined by hallucinogen use that results in clinically significantly, transient hallucinogen-specific symptoms. Recovery from Hallucinogen Intoxication is generally complete and absent of physical or mental sequelae. A pattern or repeated intoxication may or may not result in harm to a person’s physical or mental health or to the health of others. If there is continuing damage or harm as a result of repeated or continuous use of hallucinogens, a diagnosis of Harmful Pattern of Use of Hallucinogens may be assigned. If relevant at the time of the clinical encounter (e.g., in an emergency room), Harmful Pattern of Use of Hallucinogens may be diagnosed with an associated diagnosis of Hallucinogen Intoxication.
  • Boundary with Hallucinogen-Induced Mental Disorders: If a Hallucinogen-Induced Mental Disorder has occurred as a form of harm resulting from a pattern of hallucinogen use, both Harmful Pattern of Use of Hallucinogens and the relevant Hallucinogen-Induced Mental Disorder should be diagnosed (e.g., Harmful Pattern of Hallucinogen Use with Hallucinogen-Induced Anxiety Disorder).
  • Boundary with other mental disorders and other medical conditions: Numerous mental disorders as well as subthreshold symptoms may co-occur with episodic or continuous patterns of hallucinogen use. Similarly, continuous or episodic hallucinogen use increases the risk for mental disorders as well as other medical conditions. Co-occurring mental disorders and comorbid medical conditions should be diagnosed separately, along with a diagnosis of Harmful Pattern of Use of Hallucinogens.
• 6C49.2 Hallucinogen dependence

  Hallucinogen dependence is a disorder of regulation of hallucinogen use arising from repeated or continuous use of hallucinogens. The characteristic feature is a strong internal drive to use hallucinogens, which is manifested by impaired ability to control use, increasing priority given to use over other activities and persistence of use despite harm or negative consequences. These experiences are often accompanied by a subjective sensation of urge or craving to use hallucinogens. The features of dependence are usually evident over a period of at least 12 months but the diagnosis may be made if hallucinogens use is continuous (daily or almost daily) for at least 3 months. [1]

  Essential (Required) Features:

  • A pattern of recurrent episodic or continuous use of hallucinogens with evidence of impaired regulation of hallucinogen use that is manifested by two or more of the following:
    • Impaired control over hallucinogen use (i.e., onset, frequency, intensity, duration, termination, context);
    • Increasing precedence of hallucinogen use over other aspects of life, including maintenance of health, and daily activities and responsibilities, such that hallucinogen 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, such as tolerance to the effects of hallucinogens or a need to use increasing amounts of hallucinogens to achieve the same effect.
    • 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:

  A specifier is also used to describe the pattern of substance use in the context of Hallucinogen Dependence. Unlike alcohol, separate codes for continuous and episodic current use are not provided.

  6C49.20 Hallucinogen Dependence, current use

  Current Hallucinogen Dependence with episodic or continuous use of hallucinogens within the past month.

  6C49.21 Hallucinogen Dependence, early full remission

  After a diagnosis of Hallucinogen Dependence and often following a treatment episode or other intervention (including self-help intervention), the individual has been abstinent from hallucinogens during a period lasting from between 1 and 12 months.

  6C49.22 Hallucinogen Dependence, sustained partial remission

  After a diagnosis of Hallucinogen Dependence, and often following a treatment episode or other intervention (including self-help intervention), there is a significant reduction in hallucinogen 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.

  6C49.22 Hallucinogen Dependence, sustained full remission

  After a diagnosis of Hallucinogen Dependence, and often following a treatment episode or other intervention (including self-intervention), the person has been abstinent from hallucinogens for 12 months or longer.

  6C49.2Z Hallucinogen Dependence, unspecified

  Additional Clinical Features:

  • A subjective sensation of urge or craving to use hallucinogens often, but not always, accompanies the Essential Features of Hallucinogen Dependence.
  • 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 to 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 tolerances to substances.
  • Physical or mental health consequences (beyond the Essential Features of Substance Dependence) typically occur in persons 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 persons 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 specific 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.

  Boundary with Normality (Threshold):

  • Frequent or even daily substance use of hallucinogens does not automatically imply a diagnosis of Hallucinogen Dependence. There must also be evidence of the Essential Features of Hallucinogen 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 Hallucinogen Dependence, which also requires either impaired control over substance use or increasing precedence of hallucinogen 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 either 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 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.

  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.
  • 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 with Normality:

  • Boundary with Hallucinogen Intoxication: Episodic or continuous intoxication with hallucinogens is a typical feature of Hallucinogen Dependence, but is not an Essential Feature. Conversely, even if frequent and severe, Hallucinogen Intoxication alone is not a basis for a diagnosis of Hallucinogen Dependence. If all diagnostic requirements of both conditions are met for the same episode of care, Hallucinogen Dependence should be assigned as the primary diagnosis, with an associated diagnosis of Hallucinogen Intoxication (e.g., Hallucinogen Dependence with Hallucinogen Intoxication) if appropriate to the specific clinical situation (e.g., in emergency settings).
  • Boundary with Harmful Use of Hallucinogens: Hallucinogen Dependence is often associated with physical and mental health consequences, such as those seen in Harmful Pattern of Use of Hallucinogens. In the absence of the Essential Features of Hallucinogen Dependence, a diagnosis of Harmful Use of Hallucinogens can be given when there has been demonstrable harm to the individual’s physical or mental health or that of others. Harmful Pattern of Use of Hallucinogens and Hallucinogen Dependence should not be diagnosed together.
  • Boundary with Hallucinogen-Induced Mental Disorders: The impact of repeated or continuous use of substances characteristic of Hallucinogen Dependence may include Hallucinogen-Induced Mental Disorders, in which case both Hallucinogen Dependence and the relevant Hallucinogen-Induced Mental Disorder should be diagnosed (e.g., Hallucinogen Dependence with Hallucinogen-Induced Delirium).
• 6C49.3 Hallucinogen intoxication

  Hallucinogen intoxication is a clinically significant transient condition that develops during or shortly after the consumption of hallucinogens that is characterised by disturbances in consciousness, cognition, perception, affect, behaviour, or coordination. These disturbances are caused by the known pharmacological effects of hallucinogens and their intensity is closely related to the amount of hallucinogen consumed. They are time-limited and abate as the hallucinogen is cleared from the body. Presenting features may include hallucinations, illusions, perceptual changes such as depersonalisation, derealization, or synesthesias (blending of senses, such as a visual stimulus evoking a smell), anxiety, depressed or dysphoric mood, ideas of reference, paranoid ideation, impaired judgment, palpitations, sweating, blurred vision, tremors and incoordination. Physical signs may include tachycardia, elevated blood pressure, and pupillary dilatation. In rare instances, hallucinogen intoxication may facilitate suicidal ideation and behaviour. [1]

  Essential (Required) Features:

  • Transient and clinically significant disturbances in consciousness, cognition, perception, affect, behaviour, or coordination that develop during or shortly after the consumption or administration of hallucinogens.
  • The symptoms must be compatible with the known pharmacological effects of hallucinogens, and their intensity is closely related to the amount of hallucinogens consumed.
  • Presenting features of Hallucinogen Intoxication may include hallucinations, illusions, perceptual changes such as depersonalization, derealization, synesthesias (blending of senses, such as a visual stimulus evoking a smell), anxiety, depressed or dysphoric mood, ideas of reference, paranoid ideation, impaired judgment, palpitations, sweating, blurred vision, tremors and lack of coordination. Physical signs may include tachycardia, elevated blood pressure, and pupillary dilatation.
  • The symptoms of intoxication are time-limited and abate as hallucinogens are cleared from the body.
  • Symptoms are not better accounted for by another medical condition (See below) or another mental disorder, including another Disorder Due to Substance Use (e.g., Withdrawal from a different substance).

  Examples of Medical Conditions That May Present with Symptoms Similar to Substance Intoxication

  • Head injury (with or without cerebral contusion or intracranial haemorrhage or haematoma)
  • Meningitis and encephalitis
  • Diabetic ketoacidosis or hypoglycaemia
  • Hepatic or other metabolic encephalopathy
  • Wernicke’s encephalopathy
  • Electrolyte disturbance
  • Hypoxia or hypercapnia
  • Systemic infection

  Severity of Intoxication Specifier:

  Depending on the specific clinical situation and the information available, Substance Intoxication may be classified according to the level of severity as mild, moderate, or severe. The level of intoxication is usually related to the dose, route of administration, half-life, and duration of action of the substance. Severity of intoxication is also affected by individual variability (e.g., differences in body weight, substance metabolism, or tolerance). Susceptibility to substance intoxication may also be greater in individuals with comorbid medical conditions affecting drug pharmacokinetics (e.g., renal or hepatic insufficiency).

  For some substances, there are specific tests for detecting and determining the concentration of substances in bodily fluids (e.g., blood, urine), which can be important tools for clinical management. However, severity of intoxication should be determined on the basis of clinical assessment, as specified below, and not solely based on the presence and level of the substance in bodily fluids.

  The level of medical attention that may be required in response to substance intoxication varies according to the severity of intoxication and the substance involved, and varies from precautionary observation to urgent intervention to prevent death or permanent harm (e.g., administration of antagonist treatment; intubation).

  The severity of intoxication is classified using the following Extension (X) Codes in addition to the appropriate intoxication category. Extension codes are attached to the category to which they apply using an ampersand (&).

  XS5W Mild

  Mild substance intoxication is a state in which there are clinically recognizable disturbances in psychophysiological functions and responses (e.g., motor coordination, attention and judgement) that vary by substance, but there is little or no disturbance in the level of consciousness.

  The code for Hallucinogen Intoxication, mild is 6C49.3&XS5W.

  XS0T Moderate

  Moderate substance intoxication is a state in which there are marked disturbances in psychophysiological functions and responses (e.g., motor coordination, attention and judgement) that vary by substance, with substantial impairment on tasks that require these functions. There is some disturbance in level of consciousness.

  The code for Hallucinogen Intoxication, moderate is 6C49.3&XS0T.

  XS25 Severe

  Severe substance intoxication is a state in which there are obvious disturbances in psychophysiological functions and responses (e.g., motor coordination, attention and judgement) that vary by substance, with marked disturbance in level of consciousness. There is severe impairment to the extent that the person may not be capable of self-care or self-protection, and may be unable to communicate or cooperate with assessment and intervention.

  The code for Hallucinogen Intoxication, severe is 6C49.3&XS25.

  Additional Clinical Features:

  • In rare instances, Hallucinogen Intoxication may increase suicidal behaviour.
  • Psychoactive substances, whether of the same or a different pharmacological class, may interact such that they exacerbate or modify the features of intoxication. In cases of multiple psychoactive substance use in which more than one specific substance can be identified as a cause of the intoxication, it is recommended that the corresponding specific Substance Intoxication categories for each relevant substance be assigned (e.g., 6C40.3 Alcohol Intoxication and 6C49.3 Hallucinogen Intoxication) rather than 6C4F.3 Intoxication Due to Multiple Specified Psychoactive Substances.
  • Hallucinogen Intoxication may occur in the presence of medical conditions that cause impairment of levels of consciousness, cognition, perception, affect, behaviour, or coordination, which should be diagnosed separately. Determination of the aetiology of the disturbances in psychophysiological functions or responses may require longitudinal assessment.

  Boundary with Normality (Threshold):

  • Measurement of the presence or concentration of a substance in breath, blood, saliva, urine or other body fluids may be an important tool in the clinical management of Substance Intoxication. However, detection of a psychoactive substance in body fluids does not constitute a presumptive diagnosis of Substance Intoxication.

  Course Features:

  • The onset of Substance Intoxication varies according to the route of administration, the absorption of the substance and other pharmacokinetic factors. Generally, inhalation (smoking) and intravenous injecting routes lead to more rapid onset of intoxication, though oral ingestion may also lead to intoxication within minutes, depending on the substance.
  • Substance Intoxication is a transient condition, with the duration of intoxication depending on multiple factors including: (1) the dose of the substance taken, (2) the half-life and duration of action of the particular substance, and (3) the formulation of the substance taken (e.g., for pharmaceutical preparations, whether a controlled-release drug has been taken). Intoxication may last from a few minutes up to several days following the episode of use. The intensity of intoxication lessens with time after reaching a peak of absorption, and the effects eventually disappear in the absence of further use of the substance.

  Culture-Related Features:

  • The degree and characteristics of intoxication displayed for a given amount of a psychoactive substance varies considerably with circumstances, with beliefs and expectations about the effects of the substance, and with the cultural acceptability of displaying these effects. These factors result in cultural differences in the extent and manifestations of intoxication.
  • There are also genetic differences in susceptibility to intoxication with specific psychoactive substances associated with certain ethnic groups. Cultural and ethnically linked genetic factors have been better documented for alcohol than for other substances.

  Developmental Presentations:

  • Naïve users including adolescents can show features of intoxication at lower levels of use, reflecting lower physical and learned tolerance.
  • Older adults may have a lower tolerance than younger people to the effects of substances.

  Sex- and/or Gender-Related Features:

  • The amount of substance and duration of use necessary to cause intoxication differs by sex, reflecting differences in body weight and composition.
  • Behaviour while intoxicated may vary by gender, reflecting not only physiological differences, but also cultural differences and role expectations.

  Boundaries with Other Disorders and Conditions (Differential Diagnosis):

  • Boundary with Episode of Harmful Use of Hallucinogens and Harmful Pattern of Use of Hallucinogens: In Episode of Harmful Use of Hallucinogens and Harmful Pattern of Use of Hallucinogens, consumption or administration of hallucinogens results in damage to the person’s physical or mental health (including a Hallucinogen-Induced Mental Disorder) or in behaviour leading to harm to the health of others. Recovery from Hallucinogen Intoxication is generally complete. Complications due to such effects of intoxication such as injury, the effects of prolonged hyperactivity or inactivity, or other tissue damage should be diagnosed as Episode of Harmful Use of Hallucinogens or Harmful Pattern of Use of Hallucinogens, as appropriate. If relevant at the time of the clinical encounter (e.g., in emergency settings), Hallucinogen Intoxication can be given as an associated diagnosis, with Episode of Harmful Use of Hallucinogens or Harmful Pattern of Use of Hallucinogens as the primary diagnosis.
  • Boundary with Hallucinogen Dependence: Episodic or continuous intoxication with hallucinogens is a typical feature of Hallucinogen Dependence. If all diagnostic requirements of both conditions are met for the same episode of care, Hallucinogen Dependence should be assigned as the primary diagnosis, with an associated diagnosis of Hallucinogen Intoxication.
  • Boundary with Hallucinogen-Induced Delirium: Delirium is characterized by disturbances in attention, orientation, and awareness that develop within a short period of time with symptoms that are transient and may fluctuate depending on the underlying aetiology. Delirium often includes disturbance of behaviour and emotion, and may include impairment in multiple cognitive domains. Disturbance of the sleep-wake cycle may also be present. Delirium can be caused by intoxication or withdrawal from substances. When symptoms of Delirium are attributable to Hallucinogen Intoxication, an associated diagnosis of Hallucinogen-Induced Delirium should be assigned in addition to the diagnosis of Hallucinogen Intoxication.
  • Boundary with other Hallucinogen-Induced Mental Disorders: Mental or behavioural symptoms that arise during Hallucinogen Intoxication should only be used as a basis for diagnosing a Hallucinogen-Induced Mental Disorder if the intensity or duration of the symptoms is substantially in excess of those that are characteristic of Hallucinogen Intoxication and the symptoms are sufficiently severe to warrant specific clinical attention.
  • Boundary with other medical conditions: A variety of medical conditions may produce symptoms that are similar to those of Hallucinogen Intoxication. Some of these medical conditions are life-threatening requiring immediate intervention. Evidence of hallucinogen use (e.g., positive laboratory results) does not rule out the possibility of a comorbid medical condition. These alternative diagnoses must be considered in assessing Hallucinogen Intoxication. Certain medical conditions may also augment or prolong the duration of intoxication. Symptoms of intoxication that persist after they can no longer be reasonably attributed to the pharmacological effects of hallucinogens may suggest the presence of another medical condition. If it is determined that Hallucinogen Intoxication is comorbid with a medical condition, both diagnoses should be assigned.
  • Boundary with overdose: When consumption or administration of psychoactive substances results in symptoms of overdose (e.g., coma; life-threatening cardiac or respiratory suppression), it is typically more appropriate to apply a diagnosis from the grouping of Harmful Effects of Substances in the chapter on Injury, Poisoning or Certain Other Consequences of External Causes rather than Substance Intoxication.
• 6C49.4 Hallucinogen-induced delirium

  Hallucinogen-induced delirium is characterised by an acute state of disturbed attention and awareness with specific features of delirium that develops during or soon after substance intoxication or during the use of hallucinogens. The amount and duration of hallucinogen use must be capable of producing delirium. The symptoms are not better explained by a primary mental disorder, by use of or withdrawal from a different substance, or by another health condition that is not classified under Mental, behavioural and neurodevelopmental disorders. [1]

  Essential (Required) Features:

  • All diagnostic requirements for 6D70 Delirium are met.
  • There is evidence from history, physical examination, or laboratory findings that the neurocognitive disturbance is caused by the direct physiological consequences of hallucinogen use. This judgment depends on establishing that the course of the Delirium (e.g., onset, trajectory of symptoms, eventual remission with elimination of the substance from the body) is consistent with causation by hallucinogen use.
  • The duration or severity of the symptoms is substantially in excess of the characteristic syndrome of Hallucinogen Intoxication.
  • The diagnostic requirements for 6D70.2 Delirium Due to Multiple Etiological Factors are not met.

  Note: See 6D70 Delirium for other CDDR sections, including Additional Clinical Features, Boundary with Normality (Threshold), Course Features, Developmental Presentations, Culture-Related Features, and Boundaries with Other Disorders and Conditions (Differential Diagnosis).

• 6C49.5 Hallucinogen-induced psychotic disorder

  Hallucinogen-induced psychotic disorder is characterised by psychotic symptoms (e.g. delusions, hallucinations, disorganised thinking, grossly disorganised behaviour) that develop during or soon after intoxication with hallucinogens. The intensity or duration of the symptoms is substantially in excess of psychotic-like disturbances of perception, cognition, or behaviour that are characteristic of hallucinogen intoxication. The amount and duration of hallucinogen use must be capable of producing psychotic symptoms. The symptoms are not better explained by a primary mental disorder (e.g. Schizophrenia, a Mood disorder with psychotic symptoms), as might be the case if the psychotic symptoms preceded the onset of the hallucinogen use, if the symptoms persist for a substantial period of time after cessation of the hallucinogen use, or if there is other evidence of a pre-existing primary mental disorder with psychotic symptoms (e.g. a history of prior episodes not associated with hallucinogen use). [1]

  Essential (Required) Features:

  • The presentation is characterized by psychotic symptoms (e.g., delusions, hallucinations, or disorganized thinking or behaviour) that develop during or soon after intoxication with or withdrawal from hallucinogens.
  • The intensity or duration of the psychotic symptoms is substantially in excess of psychotic-like disturbances of perception, cognition, or behaviour that are characteristic of Hallucinogen Intoxication.
  • The symptoms are not better accounted for by another mental disorder such as Schizophrenia or a Mood Disorder with psychotic symptoms. Evidence supporting a diagnosis of another mental disorder would include psychotic symptoms preceding the onset of hallucinogen use, the symptoms persisting for a substantial period of time after cessation of hallucinogen use or withdrawal (e.g., 1 month or more), or other evidence of a pre-existing mental disorder with psychotic symptoms (e.g., a history of prior episodes not associated with hallucinogen use).
  • The symptoms are not a manifestation of another medical condition.
  • The symptoms cause significant distress or significant impairment in personal, family, social, educational, occupational or other important areas of functioning.

  When making a diagnosis of Hallucinogen-Induced Psychotic Disorder, an additional diagnosis indicating the related pattern of hallucinogen use should also be assigned. These include Episode of Harmful Use of Hallucinogens, Harmful Pattern of Use of Hallucinogens, and Hallucinogen Dependence. A diagnosis of Hallucinogen Intoxication may also be assigned if applicable.

  Additional Clinical Features:

  • Hallucinogen-Induced Psychotic Disorder may present with patterns of symptoms that vary according to the characteristics of the user (e.g., genetics, metabolism, personality factors). Hallucinogen use in higher amounts or over longer periods of time is more likely to be associated with the development of a Hallucinogen-Induced Psychotic Disorder.
  • Symptoms of Hallucinogen-Induced Psychotic Disorder usually resolve or improve after sustained cessation of hallucinogen use. Perceptual disturbances that last for weeks, months, or years (e.g., trails of images of moving objects, geometric illusions) can also occur as a result of hallucinogen use, primarily LSD, and are referred to as posthallucinogen perception disorder or hallucinogen-induced persisting perception disorder.
  • The duration of Substance Withdrawal for some substances can be protracted. For substances with more protracted withdrawal periods, the onset of symptoms of Substance-Induced Psychotic Disorder can occur up to several weeks after the cessation of substance use. Substance-Induced Psychotic Disorder symptoms related to substances with more protracted withdrawal periods may also last for correspondingly longer periods of time.
  • In cases in which multiple psychoactive substance are used, it is often challenging to distinguish which substance is the cause of the Substance-Induced Psychotic Disorder. When the specific etiological substance cannot be determined, a diagnosis of Substance-Induced Psychotic Disorder Due to Multiple Specified Psychoactive Substances including Medications may assigned. In cases of multiple psychoactive substance use in which more than one specific substance can be identified as a cause of the Substance-Induced Psychotic Disorder, the corresponding specific Substance-Induced Psychotic Disorder diagnoses should be given instead.

  Boundary with Normality (Threshold):

  • Symptoms of Hallucinogen-Induced Psychotic Disorders should be differentiated from transient physiological aftereffects of intoxication (‘hangover effect’). The duration or severity of the symptoms in Hallucinogen-Induced Psychotic Disorders must be in excess of ‘hangover effects’ of Hallucinogens and result in significant distress or impairment of functioning.

  Boundaries with Other Disorders and Conditions (Differential Diagnosis):

  • Boundary with Hallucinogen Intoxication: Mental or behavioural symptoms that occur during Hallucinogen Intoxication should only be used as a basis for diagnosing a Hallucinogen-Induced Psychotic Disorder if the intensity or duration of the symptoms is substantially in excess of those that are characteristic of Hallucinogen Intoxication and the symptoms are sufficiently severe to warrant specific clinical attention.
  • Boundary with Episode of Harmful Use of Hallucinogens, Harmful Pattern of Use of Hallucinogens, or Hallucinogen Dependence: The impact of repeated or continuous use of hallucinogens characteristic of Harmful Pattern of Use of Hallucinogens and Hallucinogen Dependence may include Hallucinogen-Induced Psychotic Disorder. Hallucinogen-Induced Psychotic Disorders can also be associated with a single episode of hallucinogen use. In such cases, a Hallucinogen-Induced Psychotic Disorder should be diagnosed together with a primary diagnosis of Episode of Harmful Use of Hallucinogens, Harmful Pattern of Use of Hallucinogens, or Hallucinogen Dependence.
  • Boundary with mental disorders not induced by hallucinogens: Hallucinogen-Induced Psychotic Disorders are differentiated from mental disorders with similar features that are not induced by hallucinogens on the basis of their onset, course and clinical features. A diagnosis of Hallucinogen-Induced Psychotic Disorder requires evidence from history, physical or mental examination, or laboratory findings of recent hallucinogen use, intoxication or withdrawal. Most Hallucinogen-Induced Mental Disorders resolve or improve within several weeks of cessation of hallucinogen use. Mental disorders not induced by hallucinogens may precede the onset of hallucinogen use or may continue to be symptomatic during periods of sustained abstinence. The co-occurrence of hallucinogen use or withdrawal and onset of symptoms of mental disorders should not be taken as evidence for a presumptive diagnosis of a Hallucinogen-Induced Psychotic Disorder. Some people use substances to suppress symptoms of mental disorders (e.g., Schizophrenia and Other Primary Psychotic Disorders, Mood Disorders, Anxiety and Fear-Related Disorders, Personality Disorders) and full symptomatic presentations only emerge upon cessation or reduction in substance use. Furthermore, hallucinogen use can exacerbate symptoms or precipitate an episode of a pre-existing mental disorder. Finally, hallucinogen use may be associated with but not aetiologic for new onset of symptoms of a mental disorder. Although a diagnosis of a Hallucinogen-Induced Psychotic Disorder should not be assigned under these circumstances, an additional diagnosis of Episode of Harmful Use of Hallucinogens, Harmful Pattern of Use of Hallucinogens, or Hallucinogen Dependence may still be appropriate.
• 6C49.6 Certain specified hallucinogen-induced mental or behavioural disorders

References

1. World Health Organization. International Classification of Diseases, 11th Revision, for Mortality and Morbidity Statistics (ICD-11 MMS), 2026-01 release. World Health Organization; 2026.
2. World Health Organization. Clinical Descriptions and Diagnostic Requirements for ICD-11 Mental, Behavioural or Neurodevelopmental Disorders (CDDR). World Health Organization; 2024.

WHO text reproduced without changes from the WHO ICD-11 API. © World Health Organization, licensed under CC BY-ND 3.0 IGO. View this entry in the WHO ICD-11 browser.