The use of psychoactive substances is highly prevalent and contributes substantially to risk behaviours, morbidity and mortality. The United Nations Office on Drugs and Crime World Drug Report¹ estimated that, in 2021, one in every 17 people aged 15-64 in the world had used an illicit drug in the year before. Users increased from 240 million in 2011 to 296 million in 2021, substantially more than accounted for by population growth.

Cannabis continued to be the most used illicit drug (219 million users, 4.3% of the global adult population); 36 million people had used amphetamines, 22 million cocaine, and 20 million methylenedioxymethamphetamine (MDMA or “ecstasy”) or related drugs in the previous year. An estimated 60 million people engaged in non-medical opioid use, 31.5 million of whom used opiates (i.e., non-synthetic opioids; mainly heroin).

Globally, there is very limited implementation of efficient and effective prevention strategies for substance use², and there is a substantial treatment gap for disorders due to this use³. Global evidence has called attention to the need for a new and comprehensive conceptualization of substance use disorders that incorporates the full range of relevant conditions, from risky consumption to mental disorders linked to harmful drug use⁴.

In response to these challenges, the World Health Organization (WHO) adopted a public health approach to the development of the classification of disorders due to substance use in the ICD-11. By public health approach, we refer to a broader perspective that integrates health and social aspects, aiming to benefit affected individuals and their community, and focusing on population well-being⁵.

From a public health perspective, it is essential to identify persons who exhibit a hazardous use of substances that increases the risk of harmful psychological or medical consequences, but whose symptoms do not meet the diagnostic requirements for substance use disorders. These individuals can benefit from education, prevention, and community interventions. People with diagnosable disorders need harm reduction and treatment services of differing intensities and settings, depending on the nature of their condition and the substance involved. Those who suffer physical or psychological harm due to others’ substance use should also be identified and may require services⁶.

In line with this perspective, the range of psychoactive substances classified in the ICD-11 section on disorders due to substance use has been expanded, reflecting changes in the substances associated with public health impact in different parts of the world. An extended set of substance classes will help track patterns more accurately, in order to formulate appropriate clinical and social policy responses nationally and globally. For example, a new set of categories for disorders due to synthetic cannabinoids has been added. Synthetic cannabinoids are sprayed on natural herb mixtures to mimic the euphoric effect of cannabis, and can produce respiratory depression⁷. Their use is reported in high-income countries, but little information is available for low- and middle-income countries¹.

As described in the Clinical Descriptions and Diagnostic Requirements for ICD-11 Mental, Behavioural and Neurodevelopmental Disorders (CDDR)⁸, four primary conditions are identified for each class of psychoactive substances, which are hierarchically and mutually exclusive from one another: a) hazardous substance use, which is conceptualized as a pattern of substance use that is sufficient in frequency or quantity to increase the risk of harmful physical or mental health consequences to the user or to others; since it involves incremental risk for harm that has not yet occurred, it is not considered a mental disorder (rather, it appears in the ICD-11 chapter on “Factors influencing health status or contact with health services”, facilitating early attention and advice from health professionals); b) episode of harmful substance use, which refers to an episode that has already caused harm to a person's physical or mental health or has resulted in behaviour leading to harm to the health of others, but in the absence of a known pattern of substance use; c) harmful pattern of substance use, a sub-dependence diagnosis, characterized by a persistent and repetitive pattern of substance use that has directly caused harm to the person or to someone else through the person's behaviour; and d) substance dependence, when a disorder of substance use regulation has arisen from repeated or continuous use of a substance, typically accompanied by a strong internal drive to use it.

In the ICD-11, the substance dependence diagnosis has been simplified with respect to the ICD-10. It is based on the presence of at least two of three key features: a) impaired control over substance use, b) increasing priority given to substance use over other activities, and c) physiological features of tolerance or withdrawal. Physical and mental harm is very commonly seen in substance dependence, but is not a required feature.

The CDDR indicate that clinicians may assign other substance use diagnoses in addition to one of the four primary diagnoses, depending on the specific clinical situation, including substance intoxication, substance withdrawal, and a range of substance-induced mental disorders (delirium; psychotic, mood, anxiety, obsessive-compulsive, and impulse control disorders)⁸. Additional medical diagnoses can be assigned as appropriate to describe the consequences of substance use. Clinicians can also apply a range of specifiers offering more precision in diagnosis according to the severity, course, or other manifestations of the primary and additional diagnoses.

The classification of conditions related to substance use in the ICD-11 clearly corresponds to different types of intervention needs, consistent with the WHO services pyramid framework describing the optimal mix of services for mental health⁹. Hazardous use is an appropriate target for brief interventions as well as for public health programs and primary prevention. Harmful use can be responded to in generalist settings, such as primary care, using mild or more intensive interventions depending on whether the problem is a single episode or a harmful pattern of use, and on the substance involved. The most severe cases of substance dependence are appropriately treated in more intensive specialized settings, but they represent only a small portion of the overall disease burden related to substance use. Accordingly, the ICD-11 and the CDDR will help clinicians conceptualize and communicate the most appropriate forms of treatment for specific disorders, and support public health interventions for more common but less severe presentations.

Overall, the ICD-11 and the CDDR are valuable tools for helping to reduce the gap between those who need treatment and those who receive it. They will also support improvements in drug and health policies through better characterization of different groups of people affected by substance use, who experience different types of harm and have different needs. This includes improvements in the treatment system to provide more effective alternatives for severe alcohol and drug dependence.

Implementing the new diagnostic requirements can also support a better referral system that matches the needs of different users to the services provided. It can also support improved epidemiological studies and generate more valuable data for WHO member states by providing better categories that accurately reflect substance use outcomes. Finally, and importantly, the new classification supports implementing a public health model rather than focusing only on punishment and incarceration.

精神活性物质的使用非常普遍，极大地增加了危险行为、发病率和死亡率。联合国毒品和犯罪问题办公室《世界毒品报告^1》估计，到2021年，世界上每17名15-64岁的人中就有一人在前一年使用过非法药物。用户数量从 2011 年的 2.4 亿增加到 2021 年的 2.96 亿，远高于人口增长所占的比例。

大麻仍然是最常用的非法药物（2.19 亿使用者，占全球成年人口的 4.3%）；去年，有 3,600 万人使用过安非他明、2,200 万可卡因和 2,000 万亚甲二氧基甲基安非他明（MDMA 或“摇头丸”）或相关药物。据估计，有 6000 万人从事非医疗类阿片类药物的使用，其中 3150 万人使用阿片类药物（即非合成阿片类药物；主要是海洛因）。

在全球范围内，针对物质使用²实施高效且有效的预防策略的实施非常有限，并且对这种使用引起的疾病的治疗存在很大差距³ 。全球证据呼吁人们关注对物质使用障碍进行新的、全面的概念化的必要性，其中包括从危险消费到与有害药物使用相关的精神障碍等各种相关情况⁴ 。

为了应对这些挑战，世界卫生组织 (WHO) 采用了公共卫生方法来制定 ICD-11 中物质使用所致疾病的分类。通过公共卫生方法，我们指的是整合健康和社会方面的更广泛的视角，旨在造福受影响的个人及其社区，并关注人口福祉⁵ 。

从公共卫生的角度来看，必须识别那些表现出危险使用物质的人，这会增加有害心理或医疗后果的风险，但其症状不符合物质使用障碍的诊断要求。这些人可以从教育、预防和社区干预中受益。患有可诊断疾病的人需要不同强度和环境的减少伤害和治疗服务，具体取决于其病情的性质和所涉及的物质。那些因他人使用药物而遭受身体或心理伤害的人也应被识别并可能需要服务⁶ 。

根据这一观点，ICD-11关于物质使用引起的疾病部分中分类的精神活性物质的范围已经扩大，反映了与世界不同地区的公共卫生影响相关的物质的变化。一组扩展的物质类别将有助于更准确地跟踪模式，以便在国家和全球范围内制定适当的临床和社会政策应对措施。例如，添加了一组新的合成大麻素引起的疾病类别。将合成大麻素喷洒在天然药草混合物上以模仿大麻的欣快效果，并可产生呼吸抑制⁷ 。据报道，高收入国家使用了它们，但低收入和中等收入国家的可用信息却很少¹ 。

正如 ICD-11 精神、行为和神经发育障碍 (CDDR) ⁸的临床描述和诊断要求中所述，每一类精神活性物质都确定了四个主要条件，这些条件是分层且相互排斥的： a)危险物质使用，被概念化为一种物质使用模式，其频率或数量足以增加对使用者或他人造成有害身心健康后果的风险；由于它涉及尚未发生的伤害风险增加，因此不被视为精神障碍（相反，它出现在 ICD-11 关于“影响健康状况或与卫生服务接触的因素”的章节中，有助于早期关注和建议卫生专业人员）； b)有害物质使用事件，是指已经对一个人的身体或精神健康造成伤害，或已经导致损害他人健康的行为，但没有已知的物质使用模式的事件; c)有害的物质使用模式，一种亚依赖性诊断，其特征是持续和重复的物质使用模式，直接对个人或通过个人行为对他人造成伤害； d)物质依赖，当重复或连续使用某种物质而导致物质使用调节障碍时，通常伴随着强烈的使用该物质的内在动力。

在ICD-11中，物质依赖诊断相对于ICD-10进行了简化。它基于三个关键特征中至少两个的存在：a）对物质使用的控制受损，b）物质使用比其他活动更加优先，以及c）耐受或戒断的生理特征。身体和精神伤害在物质依赖中很常见，但不是必需的特征。

CDDR 指出，除了四种主要诊断之一之外，临床医生还可以根据具体的临床情况指定其他物质使用诊断，包括物质中毒、物质戒断和一系列物质引起的精神障碍（谵妄、精神病、情绪障碍）。 、焦虑、强迫症和冲动控制障碍） ⁸ 。可以酌情指定其他医疗诊断来描述物质使用的后果。临床医生还可以根据主要诊断和附加诊断的严重程度、病程或其他表现，应用一系列说明符来提供更精确的诊断。

ICD-11 中与物质使用相关的病症分类明确对应于不同类型的干预需求，与描述心理健康最佳服务组合的世卫组织服务金字塔框架一致⁹ 。危险用途是短暂干预以及公共卫生计划和初级预防的适当目标。有害使用可以在初级保健等综合环境中进行应对，根据问题是单次发作还是有害使用模式以及所涉及的物质，使用温和或更强烈的干预措施。最严重的物质依赖病例在更集中的专业环境中得到适当治疗，但它们仅占与物质使用相关的总体疾病负担的一小部分。因此，ICD-11 和 CDDR 将帮助临床医生概念化和传达针对特定疾病的最合适的治疗形式，并支持针对更常见但不太严重的症状的公共卫生干预措施。

总体而言，ICD-11 和 CDDR 是帮助缩小需要治疗者与接受治疗者之间差距的宝贵工具。他们还将通过更好地描述受药物使用影响的不同人群（他们经历不同类型的伤害并有不同的需求）来支持改进药物和卫生政策。这包括改进治疗系统，为严重酒精和药物依赖提供更有效的替代方案。

实施新的诊断要求还可以支持更好的转诊系统，将不同用户的需求与所提供的服务相匹配。它还可以通过提供准确反映物质使用结果的更好类别来支持改进的流行病学研究并为世卫组织成员国生成更有价值的数据。最后，也是重要的是，新的分类支持实施公共卫生模式，而不是只关注惩罚和监禁。