Disorders Due to Use of Stimulants, Including Amphetamines, Methamphetamine or Methcathinone (ICD-11: 6C46)

1. Introduction

Disorders due to stimulant use represent a significant challenge for global public health, affecting millions of people in different socioeconomic and cultural contexts. This group of conditions encompasses problems related to the use of synthetic psychostimulant substances, including amphetamines, methamphetamine, methcathinone, and prescribed stimulants such as dexamphetamine.

The clinical importance of these disorders lies in their devastating consequences for the physical, mental, and social health of affected individuals. These substances possess highly dependence-producing properties and can cause significant neurobiological alterations, leading to patterns of compulsive use and loss of control. The vasoconstrictive effects of these drugs also contribute to serious cardiovascular complications, including hypertension, cardiac arrhythmias, cerebrovascular accidents, and myocardial infarctions.

The impact on public health is substantial, with increasing prevalence of methamphetamine use in various regions of the world. Associated costs include not only medical and psychiatric treatment but also social consequences such as unemployment, criminality, family disintegration, and overburdening of health and justice systems.

Correct coding using ICD-11 is critical for multiple purposes: it enables appropriate epidemiological monitoring, facilitates resource allocation for treatment, aids in scientific research, ensures appropriate reimbursement by health systems, and enables international data comparison. Diagnostic precision is also fundamental for individualized therapeutic planning and for longitudinal patient follow-up.

2. Correct ICD-11 Code

Code: 6C46

Description: Disorders due to use of stimulants, including amphetamines, methamphetamine or methcathinone

Parent category: Disorders due to substance use

Official definition: Disorders due to use of stimulants, including amphetamines, methamphetamine or methcathinone are characterized by the pattern and consequences of use of these substances. Beyond cocaine, there is a wide range of psychostimulants occurring in nature or produced synthetically. The most numerous in this group are amphetamine-type substances, including methamphetamine. Prescribed stimulants, including dexamphetamine are indicated for a limited number of conditions, such as attention-deficit/hyperactivity disorder. Methcathinone, known in many countries as ephedrone, is a potent synthetic stimulant that is structurally analogous to methamphetamine and is related to cathinone. All these drugs have, primarily, psychostimulant properties, and are also vasoconstrictive to varying degrees. They induce euphoria and hyperactivity, as can be seen in stimulant intoxication. They have potent dependence-generating properties, which can lead to the diagnosis of stimulant dependence and stimulant withdrawal following cessation of use.

This code is a fundamental part of the ICD-11 classification system for substance-related disorders, allowing diagnostic specificity and differentiation from other stimulants such as cocaine, synthetic cathinones and caffeine.

3. When to Use This Code

Code 6C46 should be used in specific clinical scenarios where there is clear evidence of disorders related to amphetamine-type stimulant use. Below are detailed practical situations:

Scenario 1: Methamphetamine Dependence with Functional Impairment Patient with a history of daily methamphetamine use via smoking for the past 18 months, presenting with inability to discontinue use despite multiple attempts, neglect of work responsibilities resulting in job loss, deterioration of family relationships, and emergence of paranoid psychotic symptoms. The patient reports strong compulsion to use and withdrawal symptoms when attempting to stop.

Scenario 2: Acute Amphetamine Intoxication with Medical Complications Individual admitted to emergency department with intense psychomotor agitation, tachycardia, severe hypertension, mydriasis, and aggressive behavior following ingestion of a large amount of amphetamines. Presents with hyperthermia and risk of cardiovascular complications. The diagnosis of stimulant intoxication is confirmed by toxicological tests.

Scenario 3: Methamphetamine-Induced Psychotic Disorder Patient with prolonged methamphetamine use developing a psychotic presentation characterized by auditory and visual hallucinations, persecutory delusions, and disorganized behavior. Symptoms emerged during the period of intensive use and persist after acute intoxication, requiring specific psychiatric intervention.

Scenario 4: Problematic Use of Prescribed Stimulants Patient initially prescribed dexamphetamine for treatment of attention-deficit/hyperactivity disorder who progressively increased doses without medical guidance, began obtaining the medication through illicit means, and developed a pattern of compulsive use with significant impairment in daily functioning.

Scenario 5: Stimulant Withdrawal Syndrome Individual with a history of chronic amphetamine use who, following abrupt cessation, presents with extreme fatigue, hypersomnia, increased appetite, depressed mood, anhedonia, and intense craving for the substance. Symptoms significantly interfere with daily activities and increase the risk of relapse.

Scenario 6: Methcathinone Use with Dependence Pattern Patient with regular use of methcathinone (ephedrone) via intravenous route, presenting with marked tolerance (need for progressively larger doses), withdrawal symptoms when not using, prioritization of substance use over other activities, and persistence of use despite infectious complications related to the route of administration.

4. When NOT to Use This Code

It is fundamental to distinguish situations where code 6C46 is not appropriate, avoiding diagnostic confusion:

Exclusion 1: Disorders due to use of synthetic cathinones (Code 1605818663) Synthetic cathinones, also known as "bath salts," are chemically distinct substances that, although sharing stimulant properties, possess different molecular structure and specific effects profile. Examples include mephedrone, methylone, and MDPV. When the disorder is specifically related to these substances, the appropriate code is 1605818663, not 6C46.

Exclusion 2: Disorders due to caffeine use (Code 31898480) Although caffeine is technically a stimulant, disorders related to its use are coded separately due to its universal legal availability, lower dependence potential, and substantially different risk profile. Problems related to excessive consumption of coffee, tea, energy drinks, or caffeine supplements should use code 31898480.

Exclusion 3: Disorders due to cocaine use (Code 1689089786) Cocaine, although a potent stimulant, has its own specific code. Differentiation is important due to pharmacokinetic particularities, patterns of use, specific medical complications, and distinct therapeutic approaches. Disorders related to crack or powder cocaine should be coded as 1689089786.

Exclusion 4: Hazardous use of stimulants including amphetamines or methamphetamine (Code 154205648) This code is reserved for situations where there is use that represents health risk, but does not yet meet full criteria for dependence or other more severe disorders. It represents an earlier stage in the spectrum of substance-related problems.

Other exclusion situations:

Primary psychotic disorders unrelated to substance use
Attention-deficit/hyperactivity disorder adequately treated with prescribed stimulants without development of problematic use
Single intoxication without established pattern of problematic use

5. Step-by-Step Coding Process

Step 1: Assess Diagnostic Criteria

Diagnostic confirmation requires systematic and comprehensive evaluation. Begin with detailed clinical history, including pattern of use (frequency, amount, route of administration, duration), previous cessation attempts, physical, psychological, and social consequences of use.

Standardized instruments can assist in the evaluation, such as structured questionnaires for identifying substance dependence. The interview should explore the presence of compulsion, loss of control, tolerance, withdrawal symptoms, neglect of important activities, and persistence of use despite negative consequences.

Complementary tests include urine toxicology for confirmation of the substance used, cardiovascular evaluation (electrocardiogram, blood pressure monitoring), laboratory tests to assess hepatic, renal, and metabolic function, and neuropsychiatric evaluation to identify comorbidities.

Step 2: Verify Specifiers

ICD-11 allows specification of different clinical presentations within code 6C46. Identify whether the case represents a single episode of intoxication, harmful use, established dependence, or stimulant-induced mental disorder.

Assess severity considering frequency of use, amount consumed, degree of functional impairment, and presence of medical or psychiatric complications. Document current status: active use, early remission (less than 12 months without problematic use), or sustained remission (more than 12 months).

Identify specific characteristics such as the presence of psychotic symptoms, mood alterations, anxiety, or cognitive symptoms induced by the substance. These specifications are relevant for therapeutic planning.

Step 3: Differentiate from Other Codes

6C40: Disorders due to use of alcohol The fundamental difference lies in the substance used and the profile of effects. Alcohol is a central nervous system depressant, whereas stimulants cause activation. Patients with alcohol use present with sedation, motor incoordination, and withdrawal symptoms characterized by tremors and risk of seizures, distinct from the presentation of stimulants.

6C41: Disorders due to use of cannabis Cannabis produces distinct psychoactive effects, including relaxation, alteration of temporal perception, and increased appetite. It does not cause the intense sympathetic activation characteristic of stimulants. Cannabis withdrawal syndrome is milder and qualitatively different.

6C42: Disorders due to use of synthetic cannabinoids Although they are synthetic substances, artificial cannabinoids act on cannabinoid receptors and do not possess primary stimulant properties. Their effects are more similar to natural cannabis, but often more intense and unpredictable.

Step 4: Required Documentation

Checklist of mandatory information:

Identification of specific substance (amphetamine, methamphetamine, methcathinone, prescribed stimulant)
Route of administration (oral, intranasal, intravenous, smoked)
Temporal pattern of use (duration, frequency, amount)
Presence of dependence criteria
Previous cessation attempts and outcomes
Medical complications identified
Psychiatric comorbidities
Functional impact (occupational, social, family)
Previous treatments and response
Complementary tests performed
Current risk assessment

The record should be objective, using standardized terminology, allowing other professionals to clearly understand the clinical presentation and the reasons for the coding chosen.

6. Complete Practical Example

Clinical Case:

A 32-year-old male patient presents to the mental health service referred by a general practitioner due to erratic behavior and reported substance use. During the initial evaluation, the patient reveals use of crystallized methamphetamine ("crystal meth") via smoking over the last 24 months.

The pattern of use began recreationally in a social context, progressing to daily use over the last 8 months. Currently, he uses the substance 4-6 times per day, remaining awake for periods of 3-4 consecutive days, followed by periods of prolonged sleep. He reports a need for progressively larger amounts to obtain the desired effects (tolerance).

He made three cessation attempts over the last 6 months, all unsuccessful due to intense symptoms of fatigue, depression, intense craving, and transient suicidal thoughts. During use, he feels energized, confident, and productive, but recognizes significant deterioration in multiple areas of his life.

He lost his job 4 months ago due to frequent absences and poor performance. His marital relationship is severely compromised, with his wife considering separation. He sold personal belongings to finance his use. He experienced two episodes of chest pain that he attributed to use, but did not seek medical attention.

In the last month, he developed paranoid symptoms, believing he is being persecuted and watched, repeatedly checking doors and windows. He also reports visual hallucinations of insects crawling under his skin, resulting in self-inflicted injuries from attempts to remove them.

On physical examination: evident weight loss (12 kg loss over 6 months), poor dental hygiene with multiple cavities, skin lesions at different stages of healing on the arms and face, tachycardia (110 bpm), elevated blood pressure (150/95 mmHg), mydriasis, mild psychomotor agitation.

Coding Step by Step:

Criteria Analysis:

Substance identified: Methamphetamine, clearly classified under code 6C46
Problematic use pattern: Daily, progressive use with loss of control
Established dependence: Presence of tolerance, withdrawal symptoms, compulsion, failed cessation attempts
Significant functional impairment: Job loss, marital problems, neglect of responsibilities
Medical complications: Cardiovascular, dental, dermatological
Induced mental disorder: Psychotic symptoms (paranoid delusions, tactile and visual hallucinations) clearly related to methamphetamine use

Code Selected: 6C46 - Disorders due to use of stimulants, including amphetamines, methamphetamine or methcathinone

Complete Justification:

Code 6C46 is appropriate because the patient presents with methamphetamine use disorder with multiple dependence criteria. The substance used (methamphetamine) is explicitly included in the definition of this code. The pattern of chronic use, with duration exceeding 12 months and daily use over the last 8 months, characterizes persistent use.

The presence of tolerance (need for larger doses), withdrawal symptoms when attempting to stop (fatigue, depression, craving), compulsion for use, and persistence despite serious consequences meet dependence criteria. Functional impairment is evident in occupational, family, and social domains.

Additionally, the patient developed a stimulant-induced psychotic disorder, characterized by paranoid delusions and hallucinations, which is one of the specific presentations contemplated within code 6C46.

Complementary Codes:

Depending on the coding system used, it may be appropriate to add codes for:

Specific cardiovascular complications identified
Stimulant-induced psychotic disorder (if the system allows dual coding to specify this presentation)
Employment and unemployment-related problems
Marital relationship problems

7. Related Codes and Differentiation

Within the Same Category:

6C40: Disorders due to use of alcohol

When to use vs. 6C46: Use 6C40 when the problematic substance is alcohol, regardless of concomitant use of stimulants. If there is problematic use of both substances, both codes may be applied.

Main difference: Alcohol is a central nervous system depressant, causing sedation, disinhibition, and acute cognitive impairment. Stimulants cause activation, euphoria, and hypervigilance. Alcohol withdrawal syndrome can be fatal (delirium tremens, seizures), whereas stimulant withdrawal, although intense, does not present direct vital risk.

6C41: Disorders due to use of cannabis

When to use vs. 6C46: Apply 6C41 when the disorder is related to use of natural cannabis. Many stimulant users also use cannabis to "mitigate" stimulant effects or facilitate sleep, but coding should reflect which substance is causing the primary disorder.

Main difference: Cannabis produces relaxation, alteration of sensory perception, increased appetite, and sedation at higher doses. It does not cause the sympathetic activation, vasoconstriction, and potential for paranoid psychotic symptoms as frequently as stimulants. The cardiovascular risk profile is substantially different.

6C42: Disorders due to use of synthetic cannabinoids

When to use vs. 6C46: Use 6C42 for disorders related to synthetic cannabinoids (such as JWH-018, K2, Spice). Although they are synthetic substances, their mechanism of action is through cannabinoid receptors, not stimulant properties.

Main difference: Synthetic cannabinoids act on the same receptors as natural cannabis but often with much greater potency and unpredictable effects. They do not possess the primary stimulant properties of amphetamines, do not cause sustained sympathetic activation, nor do they produce the same patterns of compulsive behavior observed with stimulants.

Differential Diagnoses:

Primary psychotic disorders: Schizophrenia or schizoaffective disorder may present with symptoms similar to those induced by stimulants. Differentiation is based on clear temporal relationship with substance use and resolution of symptoms with prolonged abstinence (usually days to weeks).

Bipolar disorder: Manic episodes can mimic stimulant intoxication. Longitudinal history, presence of depressive episodes, and absence of substance use during previous episodes aid in differentiation.

Anxiety disorder: Intense anxiety can occur both as a primary disorder and as induced by stimulants. Chronology is fundamental: symptoms that emerge or significantly worsen during use and improve with abstinence suggest a causal relationship.

8. Differences with ICD-10

In ICD-10, stimulant use disorders were coded primarily under F15 (Mental and behavioral disorders due to use of other stimulants, including caffeine), with subdivisions such as F15.2 for dependence syndrome and F15.5 for psychotic disorder.

Major changes in ICD-11:

ICD-11 introduces greater specificity and conceptual clarity. Code 6C46 explicitly separates amphetamine-type stimulants from other stimulants such as cocaine (which has its own code) and caffeine (also separated). This distinction recognizes important pharmacological, epidemiological, and clinical differences.

The ICD-11 structure allows better specification of clinical presentations through code extensions, facilitating more precise documentation of characteristics such as severity, presence of specific complications, and remission status.

Terminology was updated to reflect contemporary scientific knowledge about substance use disorders, abandoning potentially stigmatizing terms and adopting more neutral and clinically useful language.

Practical impact:

Healthcare professionals need to familiarize themselves with the new coding structure to ensure adequate documentation. Health information systems require updating to accommodate the new classification. The transition may temporarily hinder comparisons with historical data coded in ICD-10, but the greater precision of ICD-11 will benefit research and service planning in the long term.

The clearer separation between different types of stimulants allows better epidemiological monitoring of specific trends, such as the increase in methamphetamine use in certain regions, facilitating more targeted public health responses.

9. Frequently Asked Questions

1. How is the diagnosis of stimulant use disorders made?

The diagnosis is essentially clinical, based on detailed history and physical examination. The interview should explore pattern of use, consequences, and presence of dependence criteria. Toxicological tests confirm recent use, but do not establish the disorder diagnosis by themselves. Evaluation of medical and psychiatric complications complements the diagnosis. There is no single definitive test; the diagnosis requires integrated clinical judgment.

2. Is treatment available in public health systems?

Availability varies considerably among different regions and health systems. Many public systems offer some level of treatment, including detoxification, counseling, and outpatient treatment. Specialized chemical dependence programs frequently include care for stimulants. However, capacity may be limited, with waiting lists in some locations. Specific pharmacological treatments are limited, with the approach based primarily on psychosocial interventions.

3. How long does treatment last?

Duration is highly variable and individualized. Acute detoxification may take days to weeks. Structured outpatient treatment often lasts 3-6 months, but many patients benefit from prolonged follow-up for 12-24 months or longer. Stimulant dependence is frequently a chronic relapsing condition, requiring longitudinal management similar to other chronic diseases. Some individuals require intermittent or continuous support for years.

4. Can this code be used in medical certificates?

Use in medical certificates depends on local regulations and confidentiality considerations. In many jurisdictions, certificates to justify work absences may use more generic terminology such as "medical treatment" without specifying the exact diagnosis, protecting patient privacy. For insurance purposes or disability benefits, it may be necessary to provide the specific code, but always respecting patient consent and data protection laws.

5. Can stimulants prescribed for ADHD cause dependence?

When used as prescribed, under appropriate supervision and at therapeutic doses, the risk of developing dependence is relatively low. However, there is potential for misuse, especially if doses are increased without medical guidance, if the medication is used by non-prescribed routes (such as inhalation), or if it is shared with others. Regular monitoring is essential to identify early signs of problematic use.

6. What are the main medical complications of stimulant use?

Cardiovascular complications are particularly concerning, including hypertension, arrhythmias, myocardial infarction, and stroke, even in young individuals. Neurological complications include seizures and brain damage. Severe dental problems ("meth mouth") are common due to vasoconstriction, bruxism, and neglect of hygiene. Psychiatric complications include psychosis, depression, and anxiety. Intravenous use adds risks of infections, including HIV and hepatitis.

7. Is complete recovery possible?

Many individuals achieve sustained recovery with appropriate treatment and continued support. Recovery is a process that involves not only cessation of use, but also rebuilding functioning in multiple areas of life. Some individuals experience complete recovery without significant sequelae, while others may have persistent medical or cognitive complications. Factors that favor recovery include early treatment initiation, adequate social support, treatment of comorbidities, and engagement in a structured program.

8. How to differentiate occasional recreational use from stimulant use disorder?

Differentiation is based on the presence of negative consequences and loss of control. Occasional recreational use, although not without risks, does not necessarily constitute a disorder. The diagnosis requires a pattern of use that causes significant impairment or distress, presence of dependence criteria (tolerance, withdrawal, compulsion), and persistence of use despite negative consequences. Frequency alone does not define the disorder; functional impact and loss of control are central elements.

Conclusion

The ICD-11 code 6C46 for disorders due to stimulant use, including amphetamines, methamphetamine, or methcathinone, represents an essential tool for identification, documentation, and appropriate management of these complex conditions. Accurate coding facilitates communication among professionals, allows epidemiological monitoring, aids in resource planning, and ensures that patients receive appropriate treatment. Understanding when to use this code, differentiating it from other related conditions, is fundamental for quality clinical practice and for addressing the global challenge represented by stimulant use disorders.

External References

This article was prepared based on reliable scientific sources:

References verified on 2026-02-03

Disorders due to use of stimulants, including amphetamines, methamphetamine or methcathinone

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