WHO ICD-11 REFERENCE

ICD-11 Mental, Behavioural and Neurodevelopmental Disorders

A plain-English, non-diagnostic directory based on the WHO ICD-11 classification and its Clinical Descriptions and Diagnostic Requirements.

Reviewed against WHO ICD-11 resources on 24 August 2026

What ICD-11 is

ICD-11 is the World Health Organization’s global classification for recording and reporting diseases and health-related conditions. The 2024 Clinical Descriptions and Diagnostic Requirements support qualified professionals in identifying mental, behavioural and neurodevelopmental disorders. They are not designed as a self-diagnosis checklist.

Classification directory

Neurodevelopmental DisordersConditions arising during the developmental period that affect cognitive, language, learning, motor, attention or social-communication functioning.Schizophrenia and Other Primary Psychotic DisordersPrimary disorders involving persistent or episodic changes in perception, thought, belief, self-experience, behaviour or negative symptoms.CatatoniaA syndrome of marked psychomotor disturbance that can occur with mental disorders, substances, medicines or medical conditions.Mood DisordersDepressive and bipolar disorders characterised by episodes or enduring patterns of altered mood and related changes in energy, activity, cognition and functioning.Anxiety or Fear-Related DisordersDisorders in which excessive fear, anxiety and associated avoidance are central and cause significant impairment.Obsessive-Compulsive or Related DisordersDisorders involving intrusive thoughts, urges, images, repetitive behaviours or persistent preoccupations.Disorders Specifically Associated with StressConditions whose defining features follow exposure to stressful or traumatic events.Dissociative DisordersDisruptions in the normal integration of consciousness, memory, identity, perception, body representation or control.Feeding or Eating DisordersDisturbances of eating, feeding or related behaviour that affect health or psychosocial functioning.Elimination DisordersRepeated urination or defecation in inappropriate places beyond the expected developmental stage and not solely due to another condition.Disorders of Bodily Distress or Bodily ExperiencePersistent distressing bodily symptoms or disturbances in the experience of the body associated with excessive attention or impairment.Disorders Due to Substance Use or Addictive BehavioursHarmful patterns, dependence and clinically significant addictive behaviours involving substances, gambling or gaming.Impulse Control DisordersPersistent failure to resist recurrent impulses to perform rewarding acts that lead to harm or significant impairment.Disruptive Behaviour or Dissocial DisordersPersistent behaviour that violates age-appropriate social expectations or the rights of others.Personality Disorders and Related TraitsEnduring disturbances in self and interpersonal functioning classified dimensionally by severity and trait domains.Paraphilic DisordersPersistent patterns of atypical sexual arousal classified as disorders when they involve non-consenting individuals or cause marked distress or significant risk.Factitious DisordersIntentional production, falsification or induction of symptoms without the external incentives that define malingering.Neurocognitive DisordersAcquired disorders of cognition including acute disturbance and progressive or static decline.Mental or Behavioural Disorders Associated with Pregnancy, Childbirth or the PuerperiumMental or behavioural syndromes beginning during pregnancy or the postnatal period when the timing is clinically central.Psychological or Behavioural Factors Affecting Conditions ElsewherePsychological or behavioural factors that adversely affect the course, treatment or outcome of a medical condition.Secondary Mental or Behavioural SyndromesMental or behavioural syndromes judged to be a direct pathophysiological consequence of a medical condition classified elsewhere.Sleep-Wake Disorders Relevant to Mental HealthSleep-wake conditions classified in their own ICD-11 chapter that can overlap with mood, anxiety, cognition and wellbeing.

How to read the condition pages

Each page describes the broad clinical idea, features a qualified professional may explore, important differential questions and the responsible UK route. The text paraphrases the classification and does not reproduce WHO diagnostic requirements. Exact coding, exclusions, qualifiers and boundaries should be checked in the current WHO browser by a trained professional.

Important classification boundaries

  • A symptom is not automatically a disorder; duration, distress, impairment, context and exclusions matter.
  • Culture, age, development, disability, trauma and life stage can change presentation and interpretation.
  • Physical illness, medicines, sleep and substances can mimic or contribute to mental-health symptoms.
  • Gender incongruence is not classified as a mental disorder in ICD-11.
  • Sleep-wake disorders sit in a separate ICD-11 chapter but are included here as a relevant linked pathway.

Official WHO sources

Scope, safety and urgent help

iMetaWellness provides complementary wellbeing information and reflective support. It does not diagnose a mental disorder, select investigations, interpret results as a medical opinion, prescribe treatment or replace a GP, psychiatrist, psychologist, pharmacist or NHS service. A test is useful only when a qualified professional has a clear question and a plan for acting on the result.

If someone may act on suicidal thoughts, cannot remain safe, has severe confusion, new psychosis, collapse, seizure, chest pain or another immediate danger, call 999 or attend A&E. For urgent concerns that are not immediately life-threatening, contact NHS 111, the person’s GP, mental-health team or local crisis service.

Use this information in a responsible next step

We can help you organise observations, questions, routines and a concise summary for an appropriate professional. We do not order tests or confirm diagnoses.