Classification and Management of Mental Disorders: DSM-5-TR and ICD-11

Classification gives clinicians a shared language for describing patterns of symptoms, course, severity, causes and functional impact. It supports communication, treatment planning, research, health records and service organisation. A classification is not the patient, and a code is not a complete formulation. Diagnosis must remain a careful clinical process that includes safety, physical health, culture, development, substance use, trauma, strengths and the patient’s own goals.

Teaching materials sometimes write “DSM V” and “ICD IV.” The current DSM terminology is DSM-5-TR (the fifth edition, text revision). The WHO classification is ICD-11; ICD-10 remains important in many records and examinations. There is no current psychiatric “ICD-IV” system. Always follow the classification required by the school, hospital and national reporting system, and document the source of the code.

Learning objectives

• Explain why mental-disorder classifications are useful but cannot replace clinical formulation.
• Outline the major DSM-5-TR and ICD-11 families of mental, behavioural and neurodevelopmental disorders.
• Distinguish primary psychiatric illness from disorder due to a medical condition, substance/medication or delirium.
• Apply a biopsychosocial, culturally responsive and risk-informed management framework.
• Document a provisional or confirmed diagnosis, differential, severity, psychosocial formulation and management plan.

1. What makes a mental disorder?

A mental disorder is generally a clinically significant disturbance in cognition, emotion regulation or behaviour associated with distress, impairment, risk or loss of functioning. Distress alone is not always a disorder; cultural practices, normal grief, understandable reactions to danger and differences that do not cause clinically significant harm should not be pathologised. Conversely, a person may have a serious disorder even when they minimise symptoms or appear calm.

Core diagnostic dimensions

2. DSM-5-TR and ICD-11: how they differ

DSM and ICD categories overlap but are not always identical. Do not convert a code by memory when a precise code matters; use the current electronic browser or institutional coding manual. If the picture is incomplete, document a provisional, other-specified or unspecified diagnosis rather than inventing certainty.

3. Major families of mental and behavioural disorders

3.1 Neurodevelopmental disorders

These begin during the developmental period and affect intellectual, motor, language, communication, attention, learning or social functions. Examples include intellectual developmental disorder, autism spectrum disorder, attention-deficit/hyperactivity disorder, communication disorders, specific learning disorders, motor disorders and tic disorders.

• Assess developmental history, school/work function, adaptive skills, language, sensory impairment and collateral information.
• Rule out hearing/vision problems, epilepsy, sleep disorders, trauma, substance exposure and intellectual or neurological conditions.
• Management is developmental and environmental: education adjustments, behavioural support, family training, occupational/speech therapy, social protection and selected medication.

3.2 Schizophrenia spectrum and other primary psychotic disorders

Psychosis is a syndrome, not a diagnosis. It may involve delusions, hallucinations, disorganised thought or behaviour, negative symptoms and cognitive change. The differential includes schizophrenia, schizoaffective disorder, brief or acute psychosis, mood disorder with psychotic features, substance-induced psychosis, psychosis due to a medical condition and delirium.

• Establish duration, mood relationship, functional decline, substance exposure, physical/neurological signs and collateral history.
• Management may include antipsychotic medicine, psychological and family interventions, physical-health monitoring, substance-use treatment, supported education/employment and crisis planning.
• Treat red flags such as altered attention, fever, seizures, catatonia, head injury, immunosuppression or abrupt atypical onset as possible medical illness.

3.3 Catatonia

Catatonia is a psychomotor syndrome that may occur in mood disorders, psychosis, neurological disease, infection, autoimmune illness or medication withdrawal. Signs include stupor, mutism, negativism, posturing, waxy flexibility, echophenomena, agitation and refusal of food or fluid. Malignant catatonia with fever and autonomic instability is an emergency. Assess hydration, renal function, CK, infection, seizures, medication and medical causes, and seek specialist treatment urgently.

3.4 Bipolar and related disorders

Bipolar disorders involve episodes of mania or hypomania, often with depressive episodes. Mania includes elevated, expansive or irritable mood with increased energy and associated reduced need for sleep, pressured speech, grandiosity, racing thoughts, distractibility and risky behaviour. Assess psychosis, substance use, thyroid disease, medicines and safety.

• Acute mania may require a low-stimulation environment, antipsychotic treatment, mood stabiliser and sometimes admission.
• Long-term care includes relapse prevention, sleep/routine stabilisation, medicine monitoring, family work, psychoeducation and treatment of substance use.
• Antidepressant monotherapy can worsen mania or rapid cycling in susceptible patients; reassess the diagnosis before prescribing.

3.5 Depressive disorders

Depressive disorders involve persistent low mood or loss of interest plus cognitive, emotional, physical and behavioural symptoms. Assess duration, severity, psychosis, bipolarity, suicide risk, substances, grief, medical illness, pregnancy/postpartum state and social stress.

• Management may combine psychoeducation, behavioural activation, CBT/IPT, social support, antidepressant medicine and ECT for selected severe or life-threatening presentations.
• Do not equate a questionnaire score with a diagnosis; integrate function, risk, collateral and clinical observation.

3.6 Anxiety and fear-related disorders

These include generalised anxiety disorder, panic disorder, agoraphobia, social anxiety disorder and specific phobias. Rule out hyperthyroidism, arrhythmia, asthma, hypoglycaemia, stimulant use, medication effects and trauma. Management includes psychoeducation, CBT, graded exposure, relaxation, sleep and stimulant reduction, and medicine when indicated.

3.7 Obsessive-compulsive and related disorders

Obsessions are intrusive, recurrent thoughts or images; compulsions are repetitive behaviours or mental acts performed to reduce distress. Related conditions include body dysmorphic disorder, hoarding disorder, trichotillomania and excoriation disorder. Distinguish obsessional thoughts from delusions, ruminations, culturally accepted rituals and psychosis. CBT with exposure and response prevention and selected medicines are evidence-based approaches.

3.8 Trauma- and stressor-related disorders

Post-traumatic stress disorder, complex PTSD, adjustment disorder and prolonged grief involve symptoms after trauma, loss or major stress. Assess current danger, dissociation, substance use, depression, self-harm, sleep and physical injury. Begin with safety, stabilisation and social protection; use trained trauma-focused therapy when appropriate.

3.9 Dissociative disorders

Dissociation may involve depersonalisation, derealisation, amnesia or identity disturbance. Assess seizures, head injury, substances, sleep, trauma and neurological illness. Avoid suggestive questioning; establish safety, grounding, continuity and specialist assessment.

3.10 Feeding and eating disorders

Anorexia nervosa, bulimia nervosa, binge-eating disorder and related conditions affect eating, body image and physical health. Assess weight trajectory, vital signs, hydration, electrolytes, ECG, refeeding risk, purging, laxative use, suicide risk and osteoporosis. Medical instability overrides routine outpatient management.

3.11 Substance use and addictive behaviours

Diagnoses describe impaired control, priority given to use, continued use despite harm, tolerance, withdrawal and functional consequences. Assess the substance, dose, route, last use, overdose, withdrawal, pregnancy, infection risk, violence and co-occurring mental illness. Management ranges from brief intervention and harm reduction to medically supervised withdrawal, opioid agonist treatment, relapse prevention and rehabilitation.

3.12 Neurocognitive disorders

Delirium is acute and fluctuating with impaired attention; it is a medical emergency. Dementia or major neurocognitive disorder is a progressive decline interfering with independence. Assess cognition, function, collateral baseline, medicines, sensory impairment, infection, metabolic causes, depression and neurological signs. A cognitive score alone does not distinguish delirium from dementia.

3.13 Personality disorders and related patterns

Personality disorder classifications describe enduring patterns of inner experience and behaviour that deviate from cultural expectations, begin by adolescence or early adulthood, and cause distress or impairment. Use non-stigmatising language, assess trauma and neurodevelopmental conditions, and focus on risk, relationships, emotion regulation and evidence-based psychological treatment. Never deny emergency care because of a personality-disorder label.

3.14 Sleep-wake, sexual and other conditions

Sleep-wake disorders, sexual dysfunctions, gender incongruence, paraphilic disorders, bodily distress, impulse-control disorders and factitious disorder require careful history, consent, cultural humility and physical assessment. Do not pathologise identity or consensual adult behaviour. Diagnose only when distress, impairment, risk or clinically significant dysfunction meets the relevant criteria.

4. Differential diagnosis: the must-not-miss checklist

5. A biopsychosocial management framework

1. Safety and stabilisation: ABCDE, medical causes, observation level, suicide/violence assessment, safeguarding, hydration, nutrition and sleep.
2. Shared formulation: biological vulnerabilities, psychological processes, social determinants, culture, trauma, strengths and maintaining factors.
3. Evidence-based treatment: psychoeducation, psychological therapy, medicines, ECT or specialist interventions as indicated.
4. Physical-health care: metabolic screening, infectious disease, reproductive health, substance-related harm, chronic disease and medication monitoring.
5. Social recovery: family work, housing, education/work, finances, disability support, legal/safeguarding referrals and community care.
6. Measurement and review: symptoms, function, risk, adverse effects, patient goals, adherence and barriers.
7. Relapse prevention: early warning signs, crisis plan, means safety, follow-up, who to contact and what happens during deterioration.

6. Management by severity

7. Cultural formulation and diagnostic humility

• Ask how the patient, family and community explain the problem and what help they consider acceptable.
• Use trained interpreters and distinguish language differences from thought disorder.
• Consider spiritual experiences in cultural context without dismissing risk or automatically labelling them as psychosis.
• Recognise the effects of poverty, conflict, displacement, gender-based violence, racism, stigma and limited access to care.
• Document uncertainty, competing explanations and the information still needed.

8. Documentation template

9. Worked cases

Case 1: Confusion mistaken for psychosis

A 70-year-old with pneumonia sees insects and fluctuates between agitation and drowsiness. The syndrome is acute with impaired attention. Diagnose possible delirium, investigate and treat the medical cause, review medicines and involve family for baseline information. Do not label schizophrenia based on hallucinations alone.

Case 2: Depression with hidden bipolarity

A patient with recurrent “depression” reports periods of four nights with little sleep, unusual confidence, rapid speech and impulsive spending. Reassess for bipolar disorder before antidepressant monotherapy. Discuss mood-stabilising treatment and specialist review, and assess current risk.

Case 3: First-episode psychosis

A 21-year-old has two months of voices and social withdrawal. Complete a physical/neurological assessment, substance and collateral history, targeted investigations, risk assessment and psychosocial formulation. Start evidence-based treatment while continuing to refine the diagnosis; a first label is not the end of assessment.

10. Common classification errors

• Confusing a symptom such as anxiety, hallucination or insomnia with a complete diagnosis.
• Ignoring delirium, substances or medical disease because the patient has a psychiatric history.
• Using an outdated code or copying a DSM code into an ICD-only reporting system without checking.
• Overdiagnosing based on a questionnaire score or one brief interview.
• Pathologising cultural, spiritual, gender or developmental differences without assessing distress, impairment and context.
• Allowing a diagnosis to obscure safety, physical health, safeguarding or social needs.
• Failing to use provisional or unspecified diagnoses when information is incomplete.

11. Quick self-test

1. Why is a classification not the same as a clinical formulation?
2. What is the current WHO classification, and what does “DSM V” usually mean?
3. Name four features that make delirium different from a primary psychotic disorder.
4. List the major components of a biopsychosocial management plan.
5. Why must bipolarity be considered before antidepressant monotherapy?
6. What information helps distinguish substance-induced psychosis from primary psychosis?
7. When should a clinician document a provisional or unspecified diagnosis?
8. Why is cultural formulation important?
9. Which presentations require emergency rather than routine psychiatric management?
10. What should be recorded alongside a diagnostic code?

Answers

1. A classification organises symptoms into shared categories; formulation explains this person’s causes, context, risks, strengths and treatment needs.
2. ICD-11 is the current WHO classification; DSM V refers to DSM-5, now with a text revision called DSM-5-TR.
3. Acute onset, fluctuating course, impaired attention/awareness and a medical or substance cause are key features.
4. Safety/medical stabilisation, formulation, psychological and biological treatment, physical-health care, social recovery, monitoring and relapse prevention.
5. Antidepressants may precipitate mania or rapid cycling in a person with bipolar vulnerability and may delay correct treatment.
6. Timing of symptoms against use/withdrawal, toxicology limitations, past episodes when sober, collateral history, physical signs and persistence after abstinence.
7. When duration, collateral information, exclusion assessment or symptom pattern is incomplete; uncertainty is safer than false precision.
8. Culture shapes meaning, help-seeking, communication and acceptable experiences; it prevents misdiagnosis and improves engagement.
9. Delirium, overdose, severe withdrawal, catatonia, imminent suicide/violence, unstable medical illness, severe mania or psychosis with inability to care for basic needs.
10. Syndrome, time course, severity, differential, risk, formulation, investigations, patient goals, management, follow-up and classification system used.

References and further reading

• WHO. Clinical descriptions and diagnostic requirements for ICD-11 mental, behavioural and neurodevelopmental disorders (CDDR).
• WHO. ICD-10 Classification of Mental and Behavioural Disorders: Clinical descriptions and diagnostic guidelines.
• American Psychiatric Association. About DSM-5-TR.
• WHO. mhGAP Intervention Guide, version 2.0.
• WHO. mhGAP guideline for mental, neurological and substance use disorders, 2023.
• Use current Ugandan clinical, coding, safeguarding and medicines guidance for local diagnosis, referral and reporting.