ICD-116E63	SECONDARY ANXIETY SYNDROME Secondary anxiety syndrome
ICD-10F06.4	Organic anxiety disorder
DSM-5-TRF06.4	Anxiety Disorder Due to Another Medical Condition

1. Definition and nosology

Secondary Anxiety Syndrome (ICD-11: 6E63 Secondary Anxiety Syndrome; DSM-5-TR: F06.4 Anxiety Disorder Due to Another Medical Condition) — anxiety, panic or obsessive-like symptoms within context of another medical condition or substance effect.

2. History

Development of consultation-liaison psychiatry; formalization from DSM-III.

3. Epidemiology

• Frequency of anxiety is high in chronic medical conditions (cardiac, COPD, endocrine).
• In hyperthyroidism, 60–70% have anxiety symptoms.
• Caffeine, stimulant-induced anxiety.

4. Aetiology and pathogenesis

• Endocrine — hyperthyroidism, pheochromocytoma, hypoglycemia.
• Cardiac — arrhythmia, myocardial infarction, mitral valve prolapse.
• Respiratory — COPD, asthma, pulmonary embolism.
• Neurological — TBI, Parkinson's, MS.
• Substance/medication — caffeine, stimulant, corticosteroid, β-blocker (paradoxical), benzodiazepine/alcohol withdrawal.
• Vestibular disorders.

5. Clinical features

• GAD, panic attack, OCD-like symptoms in the context of a medical condition.
• Atypical features (late onset, focal symptoms).

6. Diagnosis

Medical evidence + distress symptoms + temporal congruence.

6.1 Source-specific specifications

DSM-5-TR / ICD-11 — same.

6.2 Diagnostic algorithm

1. Clinical interview.
2. Medical evaluation — TSH, glucose, cardiac, vestibular.
3. Medication and caffeine history.
4. Toxicology.

6.3 Differential diagnosis

• Primary anxiety disorders (6B0x);
• Delirium;
• Adjustment disorder.

7. Examination and assessment

• GAD-7, HAM-A.
• TSH, glucose, EKG.
• Toxicology.

8. Treatment

1. Etiological treatment.
2. Symptomatic — SSRIs for residual anxiety; benzodiazepines short-term for acute condition.
3. Caffeine restriction.

Treatment methods

1. Etiological Intervention — Correction of medical condition.
2. SSRI For Residual Anxiety — For residual symptoms after correction of medical condition.

9. Prognosis

Significant improvement with etiological intervention.

10. Myths and misconceptions

Myth 1: “Anxiety in a patient with a medical illness is ‘normal’”

Evidence: Clinical distress worsens the course of the medical condition; intervention required.

Myth 2: “Anxiolytics are first-line in hyperthyroidism”

Evidence: Primary is thyroid correction; β-blocker (propranolol) is a symptomatic adjunct.

Myth 3: “Caffeine is safe”

Evidence: High doses can cause panic, anxiety, and tachycardia; limitation is recommended.

11. Sources

1. WHO. ICD-11. 6E63 Secondary anxiety syndrome. 2024.
2. APA. DSM-5-TR. 2022.
3. Levenson J.L. (ed.). APA Publishing Textbook of Psychosomatic Medicine and Consultation-Liaison Psychiatry. 3rd ed. 2018.