ICD Classification

PsychologyAbnormal Psychology

The International Classification of Diseases (ICD) is a broad classification system that enumerates all the disorders or diseases that affect the human species. This classification has been prepared and revised regularly by an international team of scientists that hail from various member countries of the World Health Organization (WHO).

What is ICD-11 Classification?

Originating in the 1900s, the latest version of ICD is version 11, which has been used since 1st January 2022. The International Classification of Diseases and Related Health Problems (ICD) "as a tool for recording, reporting and grouping conditions and factors that influence health." It is a holistic classification that consists of etiology, prognosis, diagnosis, and treatment specifications of disorders. The fundamental characteristics of this system are discussed in the upcoming sections.

Characteristics of ICD Classification

  • It is multilingual
  • Its formation is based on data from across cultures and contexts
  • It has a unique coding system
  • It is available online as well as in the offline form
  • It is easy to use, accurate as well as efficient
  • It is divided into chapters based on similarity of symptoms and causes of disorders
  • This classification includes nearly all known diseases the human species may suffer, whether psychological, physiological, social, or genetic.

The latest version of ICD, i.e., ICD 11, consists of 26 chapters, a supplementary section for functioning assessment, and a section for extension codes. Most psychological disorders are enumerated in chapter 6 under the heading of 'Mental, Behavioral or Neurodevelopmental Disorders. The categorization within this chapter has been discussed in the next section.

Classification of Psychological Disorders in ICD 11 (Chapter 6)

This chapter consists of nearly all known psychological disorders. It suggests that "Mental, behavioral and neurodevelopmental disorders are syndromes characterized by clinically significant disturbance in an individual's cognition, emotional regulation, or behavior that reflects a dysfunction in the psychological, biological, or developmental processes that underlie mental and behavioral functioning. These disturbances are usually associated with distress or impairment in personal, family, social, educational, occupational, or other important areas of functioning." This chapter is further divided into 26 sections as follows:

Neurodevelopmental Disorders

  • 6A00 Disorders of Intellectual Development
  • 6A01 Developmental Speech or Language Disorders
  • 6A01.0 Developmental Speech Sound Disorder
  • 6A01.1 Developmental Speech Fluency Disorder
  • 6A01.2 Developmental Language Disorder
  • 6A02 Autism Spectrum Disorder
  • 6A03 Developmental Learning Disorder
  • 6A04 Developmental Motor Coordination Disorder
  • 6A05 Attention Deficit Hyperactivity Disorder
  • 6A06 Stereotyped Movement Disorder
  • 6A0Y Other Specified Neurodevelopmental Disorders
  • 8A05.00 Tourette Syndrome (explained in detail in chapter 8 ‘Diseases of nervous system’)
  • 8A05.01 Chronic Motor Tic Disorder (explained in chapter 8)
  • 8A05.02 Chronic Phonic Tic Disorder (explained in chapter 8)

Schizophrenia or Other Primary Psychotic Disorders

  • 6A20 Schizophrenia
  • 6A21 Schizoaffective Disorder
  • 6A22 Schizotypal Disorder
  • 6A23 Acute and Transient Psychotic Disorder
  • 6A24 Delusional Disorder
  • 6A2Y Other Specified Schizophrenia or Primary Psychotic Disorders


  • 6A40 Catatonia Associated with Another Mental Disorder
  • 6A41 Catatonia Induced by Substances or Medications
  • 6E69 Secondary Catatonia Syndrome (coded elsewhere)

Mood Disorders

  • Bipolar or Related Disorders
    • 6A60 Bipolar Type I Disorder
    • 6A61 Bipolar Type II Disorder
    • 6A62 Cyclothymic Disorder
    • 6A6Y Other Specified Bipolar or Related Disorders
  • Depressive Disorders
    • 6A70 Single Episode Depressive Disorder
    • 6A71 Recurrent Depressive Disorder
    • 6A72 Dysthymic Disorder
    • 6A7Y Other Specified Depressive Disorders
    • 6A73 Mixed Depressive and Anxiety Disorder
  • 6A8Y Other Specified Mood Disorders

Anxiety or Fear Related Disorders

  • 6B00 Generalized Anxiety Disorder
  • 6B01 Panic Disorder
  • 6B02 Agoraphobia
  • 6B03 Specific Phobia
  • 6B04 Social Anxiety Disorder
  • 6B05 Separation Anxiety Disorder
  • 6B06 Selective Mutism
  • 6B0Y Other Specified Anxiety or Fear-Related Disorders

Obsessive-Compulsive or Related disorders

  • 6B20 Obsessive-Compulsive Disorder
  • 6B21 Body Dysmorphic Disorder
  • 6B22 Olfactory Reference Disorder
  • 6B23 Hypochondriasis (Health Anxiety Disorder)
  • 6B24 Hoarding Disorder
  • 6B25 Body-Focused Repetitive Behaviour Disorders
    • 6B25.0 Trichotillomania (Hair Pulling Disorder)
    • 6B25.1 Excoriation (Skin Picking) Disorder
  • 6B2Y Other Specified Obsessive-Compulsive or Related Disorders

Disorders Specifically Associated with Stress

  • 6B40 Post-Traumatic Stress Disorder
  • 6B41 Complex Post-Traumatic Stress Disorder
  • 6B42 Prolonged Grief Disorder
  • 6B43 Adjustment Disorder
  • 6B44 Reactive Attachment Disorder
  • 6B45 Disinhibited Social Engagement Disorder
  • 6B4Y Other Specified Disorders Specifically Associated with Stress

Dissociative Disorders

  • 6B60 Dissociative Neurological Symptom Disorder
  • 6B61 Dissociative Amnesia
  • 6B62 Trance Disorder
  • 6B63 Possession Trance Disorder
  • 6B64 Dissociative Identity Disorder
  • 6B65 Partial Dissociative Identity Disorder
  • 6B66 Depersonalization-Derealization Disorder
  • 6B6Y Other Specified Dissociative Disorders

Feeding or Eating Disorders

  • 6B80 Anorexia Nervosa
  • 6B81 Bulimia Nervosa
  • 6B82 Binge Eating Disorder
  • 6B83 Avoidant-Restrictive Food Intake Disorder
  • 6B84 Pica
  • 6B85 Rumination-Regurgitation Disorder
  • 6B8Y Other Specified Feeding or Eating Disorders

Elimination Disorders

  • 6C00 Enuresis
  • 6C01 Encopresis

Disorders of Bodily Distress or Bodily Experiences

  • 6C20 Bodily Distress Disorder
    • 6C20.0 Mild Bodily Distress Disorder
    • 6C20.1 Moderate Bodily Distress Disorder
    • 6C20.2 Severe Bodily Distress Disorder
  • 6C21 Body Integrity Dysphoria
  • 6C2Y Other Specified Disorders of Bodily Distress or Bodily Experience

Disorders Due to Substance Use or Addictive Behaviors

Impulse Control Disorder

  • 6C70 Pyromania
  • 6C71 Kleptomania
  • 6C72 Compulsive Sexual Behaviour Disorder
  • 6C73 Intermittent Explosive Disorder
  • 6C7Y Other Specified Impulse Control Disorders

Disruptive Behaviour and Dissocial Disorder

  • 6C90 Oppositional Defiant Disorder
    • 6C90.0 Oppositional Defiant Disorder, with chronic irritability-anger
    • 6C90.1 Oppositional Defiant Disorder, without chronic irritability-anger
  • 6C91 Conduct-Dissocial Disorder
    • 6C91.0 Conduct-Dissocial Disorder, childhood onset
    • 6C91.1 Conduct-Dissocial Disorder, adolescent onset
  • 6C9Y Other Specified Disruptive Behaviour or Dissocial Disorders

Personality Disorders and Related Traits

  • 6D10.0 Mild Personality Disorder
  • 6D10.1 Moderate Personality Disorder
  • 6D10.2 Severe Personality Disorder
  • QE50.7 Personality Difficulty
  • 6D11.0 Negative Affectivity
  • 6D11.1 Detachment
  • 6D11.2 Dissociality
  • 6D11.3 Disinhibition
  • 6D11.4 Anankastia
  • 6D11.5 Borderline pattern

Paraphilic Disorders

  • 6D30 Exhibitionistic Disorder
  • 6D31 Voyeuristic Disorder
  • 6D32 Pedophilic Disorder
  • 6D33 Coercive Sexual Sadism Disorder
  • 6D34 Frotteuristic Disorder
  • 6D35 Other Paraphilic Disorder Involving Non-Consenting Individuals
  • 6D36 Other Paraphilic Disorder Involving Solitary Behaviour or Consenting Individuals

Factitious Disorders

  • 6D50 Factitious Disorder Imposed on Self
  • 6D51 Factitious Disorder Imposed on Another

Neurocognitive Disorders

  • 6D70 Delirium
  • 6D71 Mild Neurocognitive Disorder
  • 6D72 Amnestic Disorder
  • 6D80 to 6D85 Dementia
  • 6D8Y Dementia, Other Specified Cause
  • 6D8Z Dementia, Unknown or Unspecified Cause
  • 6E0Y Other Specified Neurocognitive Disorder
  • 6E0Z Neurocognitive Disorders, Unspecified
  • Mental or behavioural disorders associated with pregnancy, childbirth or the puerperium
  • Psychological or behavioural factors affecting disorders or diseases classified elsewhere (6E40)
  • Secondary mental or behavioural syndromes associated with disorders or diseases classified elsewhere
  • Sleep-wake disorder (chapter 7)
  • Sexual dysfunctions
  • Gender incongruence
  • Other specified mental, behavioural or neurodevelopmental disorders (6E8Y)
  • Metak, behavioural or neurodevelopmental disorders, unspecified (6E8Z)

Beyond chapter 6 of ICD 11, we see traces of psychological disorders in a few other chapters of this classification, like chapter 7 (sleep-wake disorders) and chapter 8 (disorders of nervous systems). Though ICD classification is very detailed, but a major issue is the lack of connections between disorder and multi-dimensional or axial prognosis and diagnosis of disorders.


Classification of psychological disorders is one of the initial steps toward standardizing disorders for efficient understanding and treatment of these psychological disorders. While classification, in general, can be a little confusing given the various classification systems available to clinicians, the most popular and well accepted among them are the ICD and the DSM classification systems. Though the DSM classification system has a good reach, ICD is more popular worldwide due to its association with WHO and wide cultural and contextual research base.

Updated on 13-Oct-2022 11:19:47