2.3 Describe the 2 main means of classifying mental disorder

This guide will help you answer 2.3 Describe the 2 main means of classifying mental disorder.

Mental disorders are medical conditions recognised by changes in thoughts, mood, behaviour, or how a person perceives the world. Classifying these disorders means organising them into groups based on similar features. This helps professionals diagnose and treat people accurately.

Two main systems are used to classify mental disorders:

• The International Classification of Diseases (ICD)
• The Diagnostic and Statistical Manual of Mental Disorders (DSM)

Each system uses its own set of guidelines and criteria. Understanding both helps workers offer better support to people with mental health needs.

Why Classifying Mental Disorders Matters

Classifying mental disorders brings structure and consistency to mental health support. When health and social care workers share a common language and framework, they can communicate effectively. This improves the whole journey from diagnosis and care planning to ongoing support.

Key reasons for classification include:

• Shared language across health professionals worldwide
• Clear criteria to identify mental health conditions
• Supports treatment planning and monitoring
• Helps with research into causes and treatments
• Makes it easier to collect statistics for public health

Without proper classification, people could receive inconsistent care.

The International Classification of Diseases (ICD)

What is ICD?

The International Classification of Diseases, shortened to ICD, is a global system developed by the World Health Organization (WHO). It covers all diseases, not just mental health. The mental and behavioural disorders section focuses on psychological conditions.

Role in Mental Health

The ICD gives clear definitions for mental disorders, along with codes used internationally by mental health workers, doctors, nurses, and support staff. These mental health codes appear in medical records and are used when planning or recording any kind of treatment.

For example, depression, anxiety, schizophrenia, and bipolar disorder all have their own specific codes and definitions in the ICD.

Key Features

• Used worldwide, including across the NHS in the UK.
• Free to access and update.
• Regularly reviewed and updated – the current version is ICD-11.

Structure of ICD Classification

The ICD divides mental and behavioural disorders into main groups based on features that show in thoughts, feelings, or behaviour.

Some groups include:

• Schizophrenia, schizotypal and delusional disorders
• Mood [affective] disorders (such as depression and bipolar disorder)
• Anxiety, dissociative, stress-related, and somatoform disorders
• Disorders of psychological development (including autism spectrum disorders)
• Behavioural and emotional disorders with onset usually occurring in childhood and adolescence

Each disorder has a code (like F32 for depressive episode), a definition, and a list of symptoms or signs.

How ICD is Used

In practical settings, ICD helps with:

• Diagnosis: Health professionals compare an individual’s symptoms with those listed in the ICD.
• Communication: Staff use codes to quickly share information and plan care.
• Research: Researchers use ICD categories to track patterns (epidemiology), develop treatments, and improve systems.

Benefits and Limitations

Benefits include global recognition and access, easy coding for health systems, and alignment with legal and public health requirements. Limitations are that updates take time, and some terms may seem medical or impersonal to people using services.

The Diagnostic and Statistical Manual of Mental Disorders (DSM)

What is DSM?

The DSM is produced by the American Psychiatric Association (APA). It is widely used in the United States but has a strong influence elsewhere, including parts of the UK, particularly in research and specialist mental health services.

This manual focuses on mental health disorders only, unlike the ICD which covers all diseases.

Role in Mental Health

DSM lays out the official criteria to diagnose each mental disorder. These criteria must be met for a formal diagnosis. For example, to confirm a diagnosis of major depressive disorder, specific symptoms must be present for at least two weeks and interfere with daily life.

Key Features

• Now in its fifth edition (DSM-5).
• Detailed criteria for each disorder.
• Provides checklists of symptoms and duration needed for a diagnosis.
• Often used in academic, research, and psychological testing contexts.

Structure of DSM Classification

The DSM groups mental disorders by type and by observed features:

• Neurodevelopmental disorders (such as autism and ADHD)
• Schizophrenia spectrum and other psychotic disorders
• Bipolar and related disorders
• Depressive disorders
• Anxiety disorders
• Obsessive-compulsive and related disorders
• Trauma- and stressor-related disorders
• Dissociative disorders
• Somatic symptom and related disorders
• Feeding and eating disorders
• Elimination disorders
• Sleep-wake disorders
• Sexual dysfunctions
• Gender dysphoria
• Disruptive, impulse-control, and conduct disorders
• Substance-related and addictive disorders
• Neurocognitive disorders
• Personality disorders
• Paraphilic disorders
• Others (such as other conditions needing clinical attention)

Each disorder in the DSM comes with:

• Diagnostic criteria: A checklist of symptoms and how long they must last.
• Associated features: Other traits often seen with the disorder.
• Prevalence: How common a disorder is.
• Risk factors: What increases the chance of developing the disorder.
• Differential diagnosis: Other conditions with similar symptoms to consider.

How DSM is Used

In practice, DSM helps with:

• Clinical Diagnosis: Health professionals use DSM criteria to decide if a person has a particular disorder. This can guide support and treatment.
• Assessment: It guides psychologists and psychiatrists in setting out structured interviews and self-report questionnaires.
• Research: Standard criteria make it easier for scientists to compare results and share their work.
• Education: It’s used to teach mental health professionals about mental illnesses.

Benefits and Limitations

The DSM provides detail and consistency. Its clear diagnostic criteria reduce confusion and differences between professionals. Critics say the DSM pathologises normal behaviour, runs the risk of labelling, and reflects cultural values of its place of origin.

Similarities Between ICD and DSM

Despite differences, both systems aim to provide an agreed approach to naming and recognising mental health conditions. Similarities include:

• Both create a shared language for health workers.
• Both rely on defined symptoms and signs to guide diagnosis.
• Each is regularly updated by panels of experts.
• Both influence mental health care, policy, and research worldwide.

Some disorders appear in both with near-identical criteria and terminology. This helps global research and supports people who move between countries.

Differences Between ICD and DSM

A few key differences set the ICD and DSM apart:

• Origin and use: ICD is international and covers all diseases; DSM is US-based and covers mental disorders only.
• Format: ICD uses numeric codes; DSM lists detailed criteria for each disorder.
• Updates: DSM editions appear less often; ICD is updated by WHO and revised more frequently.
• Legal status: ICD is the official diagnostic tool in the UK’s NHS; DSM is used in certain specialist and research settings.

Some specific conditions may have slightly different definitions or criteria in each system, but most major conditions align closely.

How Classifications Support Workers in Practice

Workers in health and social care rely on classification systems for many reasons. Both the ICD and DSM help in practical, day-to-day tasks:

• Supporting Assessment: Clear criteria help staff ask the right questions and notice early signs.
• Communication: Accurate use of codes and terms ensures everyone understands the nature of a person’s mental health needs.
• Care Planning: Diagnoses guide which support, therapy, or medication a person might be offered.
• Preventing Misunderstanding: Consistent use of classifications avoids confusion between workers and with families.
• Reviewing Progress: Improvements, relapses, or changes can be measured against agreed criteria or codes.
• Safeguarding: Formal diagnosis can help identify those at higher risk and put support in place.

Working with People: Considering the Impact

While classification systems act as tools, it’s important to remember each person is unique. The same diagnosis can affect people very differently. Working with people, staff should:

• Avoid using labels carelessly in conversation
• Make time to listen to each person’s story beyond the diagnosis
• Use classification information to inform, but not replace, person-centred approaches
• Respect preferences about language and self-identity
• Support rights to confidentiality and dignity at all times

Classification should guide support, not define people.

Common Terms Explained

Diagnosis

A diagnosis is an official identification of a health condition, based on observed signs and reported symptoms. Both ICD and DSM support accurate diagnosis.

Criteria

Criteria are the list of symptoms and features that must be found for a diagnosis.

Codes

Codes are a short series of letters and numbers that stand for a specific disorder. Used for records, reporting, and planning.

Differential Diagnosis

This is the process of distinguishing between disorders with similar signs or symptoms.

Classification in the UK Health and Social Care Context

In the UK, the ICD is the main system used by the NHS and in official services for coding all diseases, including mental disorders. The DSM may be used by psychiatrists, psychologists, or in specialist services, particularly when conducting formal assessments or research.

Local policies and procedures will usually refer to ICD codes for recording and reporting. Social care staff may see both systems mentioned in training or supporting documentation.

Current Developments

As of 2024, ICD-11 has been adopted by many countries, bringing updated language and categories. DSM-5 continues to be revised and expanded by the American Psychiatric Association. Both systems now pay more attention to culture, development, and how disorders may look different in different populations.

Summary Table

Feature	ICD	DSM
Developed by	World Health Organization (WHO)	American Psychiatric Association
Main use	International	United States, research
Scope	All diseases and disorders	Mental disorders only
Format	Codes (e.g. F32)	Detailed criteria, narrative
Used in UK	NHS and most national services	Some mental health/research areas
Major version	ICD-11	DSM-5

Final Thoughts

Classifying mental disorders makes it possible for health and social care workers to provide clear, fair, and effective support. The two main means of classification — the International Classification of Diseases (ICD) and the Diagnostic and Statistical Manual of Mental Disorders (DSM) — each offer their own structures, benefits, and uses.

By understanding how these systems work, and recognising their strengths and limits, workers can better support people who live with mental health conditions. They are tools to aid communication, diagnosis, planning, and respect for all individuals receiving care.