ICD-10 diagnostic categories for mental and behavioural disorders

Q: What is the structure of an ICD-10 code?

An ICD-10 code has the format letter plus two digits plus an optional digit after the dot: the general form is F . . The first letter denotes the chapter (F = mental and behavioural disorders), the two digits the group and subgroup, and the digit after the dot a subtype or specifier. Example: F33.1 means recurrent depressive disorder (F33), current episode moderate (.1). The code can be three or four characters long. ICD-11 has replaced this system with alphanumeric codes in the digit plus letter plus digits format – for example recurrent depressive disorder has the new code 6A71.

Q: Is ICD-10 still in use?

Yes. Although ICD-11 was approved by the World Health Organization in 2019 and entered into force in 2022, many countries – including Poland – still use ICD-10 in medical records, billing and health statistics. Full migration to ICD-11 requires updates to the IT systems of medical entities, official translation of the CDDR document, and staff training, which is taking place gradually. In psychiatry and clinical psychology, ICD-10 codes (for billing) and ICD-11 (for scientific and educational purposes) are increasingly used in parallel.

Q: How does Chapter V of ICD-10 differ from Chapter 6 of ICD-11?

The differences are both structural and substantive. Structurally: ICD-10 used 11 groups (F00-F99), ICD-11 introduces 21 groups (6A0-6E6), with separate chapters for neurodevelopmental, dissociative, obsessive-compulsive and related, and stress-related disorders. Substantively: ICD-11 introduces entirely new entities absent from ICD-10 – complex PTSD (6B41), prolonged grief disorder (6B42), gaming disorder (6C51), compulsive sexual behaviour disorder (6C72), body-focused repetitive behaviours (6B25). It has also changed the structure of personality disorders – instead of ten types F60.0-F60.9 of ICD-10, ICD-11 introduces a single diagnosis 6D10 plus optional trait domains and a borderline pattern. The classification of catatonia has been separated into its own group (6A4) rather than a schizophrenia subtype. A clearer dimensional approach has also been introduced, in which disorders are described by the intensity of features on a scale, not only as closed categories.

Patryk Malejka, MSc in Psychology (clinical specialisation) · 26 May 2026 · Source: WHO ICD-10 Chapter V (F00–F99)

Although ICD-11 has been in force since 2022, ICD-10 remains the leading standard in medical records and health-fund billing in many countries, including Poland. This guide presents all eleven main categories of Chapter V of ICD-10 (F00–F99) and their clinical meaning.

Structure of Chapter V of ICD-10

Chapter V of ICD-10 covers all mental, behavioural and developmental disorders. Codes have the format letter plus digits: the first letter F identifies the chapter, the next two digits identify the group and subgroup, and an optional digit after the dot identifies a subtype or specifier. Example: F33.1 means recurrent depressive disorder, current episode moderate.

The classification is hierarchical and groups related disorders in neighbouring codes. The full structure covers eleven parent groups from F00 to F99 plus a residual code F99 for unspecified disorders.

The eleven parent groups F00–F99

Code	Group	Selected subgroups
`F00–F09`	Organic, including symptomatic, mental disorders	F00 dementia in Alzheimer's disease, F01 vascular dementia, F02 dementia in other diseases, F03 unspecified dementia, F05 delirium, F07 personality and behavioural disorders due to brain disease, damage and dysfunction
`F10–F19`	Mental and behavioural disorders due to psychoactive substance use	F10 alcohol, F11 opioids, F12 cannabinoids, F13 sedatives or hypnotics, F14 cocaine, F15 other stimulants, F16 hallucinogens, F17 tobacco, F18 volatile solvents, F19 multiple drug use
`F20–F29`	Schizophrenia, schizotypal and delusional disorders	F20 schizophrenia, F21 schizotypal disorder, F22 persistent delusional disorders, F23 acute and transient psychotic disorders, F25 schizoaffective disorders
`F30–F39`	Mood (affective) disorders	F30 manic episode, F31 bipolar affective disorder, F32 depressive episode, F33 recurrent depressive disorder, F34 persistent mood disorders (dysthymia, cyclothymia)
`F40–F48`	Neurotic, stress-related and somatoform disorders	F40 phobic anxiety disorders, F41 other anxiety disorders, F42 obsessive-compulsive disorder, F43 reaction to severe stress and adjustment disorders (PTSD F43.1), F44 dissociative, F45 somatoform, F48 other neurotic
`F50–F59`	Behavioural syndromes associated with physiological disturbances and physical factors	F50 eating disorders (anorexia F50.0, bulimia F50.2), F51 non-organic sleep disorders, F52 sexual dysfunction, F53 disorders associated with the puerperium
`F60–F69`	Disorders of adult personality and behaviour	F60 specific personality disorders (paranoid, schizoid, dissocial, borderline, histrionic, anankastic, anxious, dependent), F63 habit and impulse disorders, F64 gender identity disorders (note: moved out of Chapter 6 in ICD-11), F65 paraphilias
`F70–F79`	Mental retardation (in ICD-11: disorders of intellectual development)	F70 mild, F71 moderate, F72 severe, F73 profound, F79 unspecified
`F80–F89`	Disorders of psychological development	F80 specific developmental disorders of speech and language, F81 specific developmental disorders of scholastic skills (dyslexia F81.0), F82 motor, F84 pervasive developmental disorders (autism F84.0, Asperger F84.5)
`F90–F98`	Behavioural and emotional disorders with onset usually in childhood and adolescence	F90 hyperkinetic disorders (ADHD), F91 conduct disorders, F93 emotional, F94 of social functioning, F95 tic disorders (Tourette F95.2), F98 other behavioural and emotional
`F99`	Unspecified mental disorder	F99 mental disorder, not otherwise specified

Comparison with Chapter 6 of ICD-11

ICD-11 retains most of the substantive areas of ICD-10 but reorganises them into 21 parent groups (6A0–6E6) instead of 11. The most important structural differences:

Separate groups: neurodevelopmental disorders (6A0), obsessive-compulsive and related (6B2), stress-related (6B4), dissociative (6B6) received their own chapters instead of being dispersed in F4.
New entities: complex PTSD (6B41), prolonged grief disorder (6B42), gaming disorder (6C51), compulsive sexual behaviour disorder (6C72), body-focused repetitive behaviours (6B25).
New structure of personality disorders: instead of ten types F60.0–F60.9, ICD-11 introduces a single diagnosis 6D10 plus optional trait domains (negative affectivity, dissociality, disinhibition, anankastia, detachment) and an optional borderline pattern.
Separated catatonia: ICD-11 separates catatonia (6A4) from a subtype of schizophrenia into its own group.
Moved categories: gender identity disorders F64 have been removed from the mental disorders chapter and moved to a new chapter HA60–HA6Z (Conditions related to sexual health).

Frequently asked questions

What are the main diagnostic categories covered in ICD-10 for mental and behavioral disorders?

Chapter V of ICD-10 divides mental and behavioural disorders into eleven main groups coded from F00 to F99: F00–F09 organic (dementias, delirium), F10–F19 substance-related, F20–F29 schizophrenia and related, F30–F39 mood disorders (depression F32, F33; bipolar F31), F40–F48 neurotic and stress-related (anxiety F40-F41, OCD F42, PTSD F43.1), F50–F59 eating (anorexia F50.0), sleep, sexual dysfunctions, F60–F69 personality (F60.0–F60.9), F70–F79 mental retardation, F80–F89 psychological development (autism F84.0), F90–F98 childhood-onset (ADHD F90), F99 unspecified.

What is the structure of an ICD-10 code?

An ICD-10 code has the format F<XX>.<Y>: the letter F denotes the chapter (mental and behavioural disorders), two digits denote the group and subgroup, and a digit after the dot denotes a subtype or specifier. Example: F33.1 = recurrent depressive disorder (F33), current episode moderate (.1). The code can be three or four characters long. ICD-11 has replaced this system with alphanumeric codes in the digit plus letter plus digits format — for example recurrent depressive disorder has the new code 6A71.

Is ICD-10 still in use?

Yes. Although ICD-11 was approved by WHO in 2019 and entered into force in 2022, many countries — including Poland — still use ICD-10 in medical records, health-fund billing and health statistics. Full migration requires updates to IT systems, an official translation of the CDDR document and staff training, which is taking place gradually. In psychiatry and clinical psychology, ICD-10 codes (for billing) and ICD-11 (for scientific and educational purposes) are increasingly used in parallel.

How does Chapter V of ICD-10 differ from Chapter 6 of ICD-11?

Structurally: ICD-10 used 11 groups (F00–F99), ICD-11 introduces 21 groups (6A0–6E6) with separate chapters for neurodevelopmental, dissociative, obsessive-compulsive and related, and stress-related disorders. Substantively: ICD-11 introduces entirely new entities — complex PTSD (6B41), prolonged grief disorder (6B42), gaming disorder (6C51), compulsive sexual behaviour disorder (6C72), body-focused repetitive behaviours (6B25). It has changed the structure of personality disorders — instead of ten types F60.0–F60.9, a single diagnosis 6D10 plus optional trait domains. The classification of catatonia has been separated as its own group (6A4) rather than a schizophrenia subtype.

Is a diagnosis made under ICD-10 still valid after ICD-11 was introduced?

Yes. A diagnosis made under ICD-10 remains valid and does not require automatic conversion. WHO has prepared official ICD-10 to ICD-11 mapping tables available on the ICD-11 Browser platform. During the period of coexistence in Poland, records often contain both codes in parallel, which facilitates continuity of care and reporting. The clinician decides on conversion of the patient's diagnosis at the next review.