Anxiety symptoms are among the most common psychiatric manifestations of medical illness, and the consultation-liaison psychiatrist is often asked to disentangle a primary anxiety disorder from anxiety driven by an underlying physiologic process. DSM-5-TR codes this entity as Anxiety Disorder Due to Another Medical Condition (300.09 / F06.4), reserved for clinically significant anxiety judged to be the direct pathophysiologic consequence of a medical condition rather than a psychological reaction to illness. The diagnosis matters because management hinges on treating the underlying disease — thyrotoxicosis, pheochromocytoma, pulmonary embolism, complex partial seizures, and several drug toxidromes can all masquerade as panic. Recognition is high-yield for boards and high-stakes at the bedside; missing a hyperthyroid storm or an unstable arrhythmia behind "panic attacks" is a classic clinical error. The bottom line is simple: when anxiety arrives without a coherent psychiatric narrative, atypically late in life, or with prominent autonomic or neurologic findings, work the medical differential before settling on a primary diagnosis.

Population-level estimates for the DSM-5-TR category specifically are scarce because most epidemiologic studies bundle secondary anxiety with primary anxiety disorders or with adjustment disorders. What is well-established is that anxiety symptoms are common in medically ill populations and are frequently under-recognized.^1-2

Prevalence and clinical context

• Anxiety symptoms are reported in roughly 10-30% of patients in general medical and primary care settings, with rates varying by illness type and severity.^1-2
• Among hospitalized cardiac patients, point prevalence of clinically significant anxiety has been reported at 20-40%, although only a minority meet criteria for a secondary anxiety syndrome rather than adjustment or primary anxiety disorder.³
• Hyperthyroidism is associated with anxiety symptoms in a majority of untreated patients; resolution typically follows euthyroid restoration.⁴
• Up to half of patients with chronic obstructive pulmonary disease meet criteria for an anxiety syndrome at some point in their illness, with overlap between dyspnea-driven panic and a true secondary syndrome.⁵

Demographic and risk patterns

• New-onset anxiety after age 40 in a previously psychiatrically well patient should raise suspicion for a medical etiology.⁶
• The female predominance characteristic of primary anxiety disorders is attenuated in secondary anxiety; sex distribution instead tracks the epidemiology of the underlying medical condition.^6-7
• Comorbid depression, cognitive impairment, and substance use are common and complicate diagnostic attribution.^1,7
• Polypharmacy in older adults is a major risk factor; anxiety from corticosteroids, sympathomimetics, levothyroxine over-replacement, and stimulant decongestants is frequently mistaken for late-onset GAD.⁸

The mechanism is whatever the underlying medical condition does to autonomic, endocrine, or limbic circuitry. Unlike primary anxiety disorders, the explanatory model is the disease, not a stable psychiatric trait.^6,9

Endocrine drivers

• Hyperthyroidism produces anxiety, tremor, palpitations, and heat intolerance through increased beta-adrenergic sensitivity and elevated metabolic rate.⁴
• Pheochromocytoma releases catecholamines paroxysmally, producing episodic anxiety with hypertension, headache, and diaphoresis — the classic triad.¹⁰
• Hypoglycemia activates counter-regulatory adrenergic responses and is a frequently missed cause of episodic anxiety in patients on insulin or sulfonylureas.¹¹
• Hypercortisolism (Cushing syndrome) and primary hyperparathyroidism are less common but recognized contributors.¹²

Cardiopulmonary drivers

• Pulmonary embolism, arrhythmia (especially supraventricular tachycardia and atrial fibrillation), and acute coronary syndromes can present with anxiety as the prominent subjective complaint.¹³
• COPD and asthma generate anxiety through hypoxia, hypercapnia, and conditioned fear of suffocation; the locus coeruleus and amygdala are implicated in the neurobiology of dyspnea-anxiety coupling.^5,14

Neurologic drivers

• Complex partial seizures of temporal lobe origin can produce ictal fear that mimics panic, often with brief duration, stereotypy, and post-ictal confusion.¹⁵
• Migraine, multiple sclerosis, traumatic brain injury, and Parkinson disease are associated with anxiety syndromes through diverse mechanisms involving limbic, brainstem, and basal ganglia circuitry.^16-17
• Vestibular dysfunction produces a phenotype dominated by dizziness and avoidance that can be misread as agoraphobia.¹⁸

Inflammatory and other drivers

• Anti-NMDA receptor encephalitis and other autoimmune encephalitides can present with anxiety, agitation, and psychosis, particularly in young women with ovarian teratomas.¹⁹
• Pancreatic and other malignancies are associated with anxiety syndromes that occasionally precede the diagnosis of cancer.²⁰

Integrative model

• Final common pathway involves sympathoadrenal activation, locus coeruleus firing, and amygdala-driven fear circuitry, regardless of upstream cause.⁹
• The clinical task is identifying the upstream driver, because symptomatic anxiolysis without disease-directed treatment is incomplete and sometimes dangerous (e.g. masking thyrotoxic storm or pheochromocytoma).^6,10

DSM-5-TR places this disorder among the anxiety disorders and frames it as a direct physiologic consequence of a medical condition, not a psychological reaction to being ill. The clinician's job is to establish that link by history, examination, laboratory data, or imaging.²¹

Core DSM-5-TR criteria (paraphrased)

• Prominent panic attacks or anxiety dominate the clinical picture.²¹
• Evidence from history, physical exam, or laboratory findings supports that the disturbance is the direct pathophysiologic consequence of another medical condition.²¹
• The disturbance is not better explained by another mental disorder, including an adjustment disorder with anxiety triggered by the stressor of having a serious medical illness.²¹
• The disturbance does not occur exclusively during a delirium.²¹
• The symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.²¹

Coding and specifiers

• Code 293.84 (F06.4) in DSM-5-TR; the medical condition is named in the diagnosis (e.g. "Anxiety disorder due to hyperthyroidism").²¹
• DSM-5-TR removed the previous specifiers "with generalized anxiety," "with panic attacks," and "with obsessive-compulsive symptoms" from this disorder category in earlier revisions; current practice is to describe the predominant phenotype in the narrative.²¹

ICD-11 alignment

• ICD-11 codes secondary anxiety under 6E63 "Secondary anxiety syndrome" within the broader category of secondary mental or behavioural syndromes associated with disorders or diseases classified elsewhere.²²
• Functionally equivalent to the DSM-5-TR construct, with the same requirement that the syndrome be a direct consequence of an underlying condition.²²

The phenotype mirrors primary anxiety — panic-like surges, generalized worry, autonomic hyperarousal — but the trajectory and accompanying signs usually betray the medical driver. Pattern recognition is the core skill.^6,21

Common phenotypes

• Panic-like episodes with prominent autonomic features (palpitations, diaphoresis, tremor, dyspnea), often paroxysmal and stereotyped.^10,13
• Generalized anxiety with persistent worry, restlessness, and sleep disturbance, frequently in the setting of endocrine or inflammatory illness.^4,12
• Phobic avoidance secondary to a feared somatic event (e.g. avoidance of exertion after a cardiac event, avoidance of upright posture in vestibular disease).¹⁸

Red flags pointing toward a medical etiology:

• New onset after age 40 in a patient with no psychiatric history.⁶
• Atypical course: episodic, paroxysmal, or stereotyped attacks without identifiable psychological triggers.¹⁰
• Prominent autonomic findings during episodes — sustained hypertension, tachyarrhythmia, severe diaphoresis, headache.¹⁰
• Focal neurologic signs, altered consciousness, or post-event confusion.¹⁵
• Constitutional symptoms (weight loss, fevers, night sweats) or examination findings (goiter, exophthalmos, abdominal mass).⁴
• Poor or paradoxical response to standard anxiolytic treatment.⁶

The differential is broad because the diagnosis is, by definition, the residual after primary psychiatric and substance/medication causes are excluded and a medical etiology is established. Work it systematically.^6,21

Primary anxiety disorders

• Panic disorder: recurrent unexpected panic attacks with persistent worry about future attacks; typical onset in adolescence to early adulthood, often in patients with anxious temperament.²¹
• Generalized anxiety disorder: persistent worry across multiple domains for at least six months; typically chronic and lacks paroxysmal autonomic crises.²¹
• Specific phobia, social anxiety disorder, agoraphobia: situationally cued, with stable triggers and avoidance patterns.²¹

Substance- and medication-induced anxiety

• Stimulants (cocaine, amphetamines, methylphenidate), caffeine, and sympathomimetic decongestants (pseudoephedrine, phenylephrine) commonly produce anxiety states.⁸
• Withdrawal from alcohol, benzodiazepines, opioids, and gabapentinoids generates pronounced anxiety and autonomic activation.²³
• Corticosteroids, levothyroxine over-replacement, beta-agonists (albuterol), thyroid extracts, and high-dose theophylline are recurrent iatrogenic culprits.⁸
• Coded separately as Substance/Medication-Induced Anxiety Disorder when the temporal link to the substance is established.²¹

Other psychiatric conditions

• Adjustment disorder with anxiety: anxiety as a psychological response to an identifiable stressor (including the stressor of being medically ill), without a direct physiologic mechanism.²¹
• PTSD and acute stress disorder: trauma-linked, with characteristic re-experiencing and avoidance.²¹
• Major depressive disorder and bipolar disorder: anxiety is common but secondary to mood phenomenology.²¹
• Delirium: fluctuating attention and consciousness; anxiety may be present but is not the primary disturbance.²¹
• Somatic symptom disorder and illness anxiety disorder: somatic preoccupation without proportionate physiologic findings.²¹

High-yield medical mimics

• Thyrotoxicosis: anxiety, tremor, tachycardia, weight loss, heat intolerance.⁴
• Pheochromocytoma: paroxysmal hypertension, headache, diaphoresis, palpitations.¹⁰
• Hypoglycemia: episodic anxiety with diaphoresis, tremor, hunger, relieved by glucose.¹¹
• Cardiac arrhythmia, particularly SVT and atrial fibrillation: palpitations and a sense of dread.¹³
• Pulmonary embolism: dyspnea and "impending doom," often with tachycardia and hypoxemia.¹³
• Complex partial seizures: stereotyped ictal fear, brief duration, post-ictal confusion.¹⁵
• Asthma and COPD exacerbations: dyspnea-driven anxiety, often with measurable airflow limitation.⁵
• Carcinoid syndrome: flushing, diarrhea, and anxiety from vasoactive mediator release.⁴⁷
• Anti-NMDA receptor encephalitis: anxiety, agitation, psychosis, dyskinesias, autonomic instability.¹⁹

The assessment is structured around two questions: does the temporal and clinical pattern fit a medical driver, and which workup is justified by the clinical picture? Avoid both reflexive psychiatric labeling and shotgun laboratory testing.^6,24

History elements that should not be skipped:

• Onset, duration, frequency, triggers, and stereotypy of episodes.⁶
• Full medication review including over-the-counter products, supplements, herbal preparations, and recent changes in dose or formulation.⁸
• Substance use history with attention to caffeine, nicotine, alcohol, cannabis, stimulants, and any history of withdrawal phenomena.²³
• Constitutional review: weight change, heat or cold intolerance, palpitations, headache, paroxysmal sweating, syncope, gastrointestinal symptoms.^4,10
• Family history of endocrine, cardiac, and neurologic conditions including familial pheochromocytoma syndromes (MEN2, von Hippel-Lindau).¹⁰

Physical examination

• Vital signs including orthostatics; sustained or paroxysmal hypertension warrants attention.¹⁰
• Thyroid examination for goiter, nodules, bruit, and signs of Graves disease (exophthalmos, lid lag).⁴
• Cardiopulmonary examination including auscultation for arrhythmia, murmurs, and signs of heart failure.¹³
• Neurologic examination including cognitive screen, cranial nerves, and gait.^15,17

Laboratory and imaging — directed, not reflexive:

• Baseline: TSH (with free T4 if abnormal), CBC, comprehensive metabolic panel, glucose.^4,24
• ECG when episodes include palpitations, syncope, or chest discomfort; ambulatory monitoring (Holter or event recorder) if paroxysmal arrhythmia is suspected.¹³
• Plasma free metanephrines or 24-hour urinary metanephrines and catecholamines when pheochromocytoma is on the differential (paroxysmal hypertension, headache, diaphoresis, palpitations).¹⁰
• 24-hour urine free cortisol or overnight dexamethasone suppression test when Cushing syndrome is suspected.¹²
• Toxicology screen and serum or breath alcohol when substance involvement is plausible.²³
• EEG when stereotyped paroxysmal episodes, post-event confusion, or focal symptoms suggest seizure.¹⁵
• Neuroimaging (MRI preferred) when focal neurologic findings, atypical headache, or first-onset late-life anxiety is present.¹⁷
• Autoimmune encephalitis panel when anxiety presents with subacute psychosis, seizures, dyskinesias, or autonomic instability.¹⁹

Validated rating scales

• GAD-7 (Generalized Anxiety Disorder 7-item) for symptom severity tracking, not for diagnostic differentiation.²⁵
• HAM-A (Hamilton Anxiety Rating Scale) commonly used in research and inpatient settings.²⁶
• PHQ-9 for concurrent depression screening, given high comorbidity.²⁷
• The Hospital Anxiety and Depression Scale (HADS) was developed for medically ill populations and minimizes confounding by somatic items.²⁸

Treatment is anchored to the underlying medical condition; symptomatic anxiolysis is layered on top when symptoms remain disabling or pose their own risk. The hierarchy is disease-directed treatment first, then targeted symptomatic care.^6,24

Disease-directed treatment

• Hyperthyroidism: antithyroid drugs (methimazole, propylthiouracil), radioactive iodine, or thyroidectomy as appropriate; beta-blockade with propranolol controls adrenergic symptoms during titration.⁴
• Pheochromocytoma: alpha-blockade (phenoxybenzamine or doxazosin) before beta-blockade, followed by surgical resection; unopposed beta-blockade can precipitate hypertensive crisis.¹⁰
• Hypoglycemia: glucose for acute relief and adjustment of the offending hypoglycemic regimen; investigation for insulinoma if recurrent and unexplained.¹¹
• Cardiac arrhythmia: rate or rhythm control and treatment of underlying cardiac disease per cardiology guidelines.¹³
• Respiratory disease: optimization of bronchodilators, inhaled corticosteroids, and pulmonary rehabilitation; pulmonary rehabilitation reduces dyspnea-related anxiety in COPD.⁵
• Seizure disorders: appropriate antiseizure medication; anxiety often improves with seizure control.¹⁵
• Autoimmune encephalitis: immunotherapy (corticosteroids, IVIG, plasma exchange, rituximab) and tumor removal when applicable, coordinated with neurology.¹⁹
• Iatrogenic anxiety: dose reduction or discontinuation of the offending agent when feasible; substitution of less anxiogenic alternatives.⁸

Pharmacotherapy

• High-quality trials specific to Anxiety Disorder Due to Another Medical Condition are limited; most guidance is extrapolated from primary anxiety disorder literature and clinical experience.^2,29
• SSRIs and SNRIs are reasonable first-line agents when symptomatic treatment is needed beyond disease-directed care; sertraline, escitalopram, and venlafaxine have the broadest anxiety-disorder evidence base.²⁹
• Beta-blockers (propranolol, atenolol) target peripheral autonomic symptoms and are particularly useful in thyrotoxicosis and performance-anxiety phenotypes; contraindicated in unstable asthma and decompensated heart failure.^4,30
• Benzodiazepines provide rapid relief but should be limited in duration and avoided in older adults, those with respiratory failure, substance use disorders, or cognitive impairment.³¹
• Buspirone is an option for chronic generalized anxiety phenotypes without acute autonomic crisis; slow onset limits utility in panic-like presentations.²⁹
• Hydroxyzine is a non-habit-forming option for short-term symptomatic anxiety, with sedation and anticholinergic effects as the main limitations.²⁹
• Avoid drugs that worsen the underlying condition: stimulants and sympathomimetics in cardiac or thyroid disease, benzodiazepines in respiratory failure, and serotonergic agents combined with linezolid or MAOIs.³²

Psychotherapy

• Cognitive behavioral therapy targeting illness-related catastrophic cognitions and avoidance behaviors has evidence in cardiac, pulmonary, and oncologic populations.³³
• Mindfulness-based interventions have moderate evidence for anxiety in chronic medical illness.³⁴
• Brief supportive psychotherapy and psychoeducation about the underlying disease often reduce anxiety substantially without specific anxiolysis.^6,36
• Pulmonary rehabilitation programs that include cognitive-behavioral components reduce panic and anxiety in COPD.⁵

Neuromodulation

• No specific evidence base supports neuromodulation for anxiety due to a medical condition; transcranial magnetic stimulation and ECT are not first-line and are reserved for refractory comorbid mood pathology under specialist guidance.^6,29

Adjunctive

• Sleep optimization, caffeine reduction, and graded physical activity (when medically safe) reduce baseline arousal and improve outcomes.³⁵
• Coordination with the treating medical team is essential; recurrent psychiatric consultation often outperforms one-off recommendations.³⁶

Harms cluster in two places: adverse effects of symptomatic anxiolysis layered on top of medical illness, and the hazard of mistaking secondary anxiety for a primary disorder. The evidence base is also thinner than for primary anxiety disorders.^6,24

Adverse effect profile

• SSRIs/SNRIs: nausea, sexual dysfunction, hyponatremia (especially in older adults and those on diuretics), bleeding risk in patients on antiplatelet or anticoagulant therapy, and discontinuation syndrome with abrupt cessation.³⁷
• Beta-blockers: bronchospasm in reactive airway disease, bradycardia, hypotension, fatigue, masking of hypoglycemia symptoms; unopposed beta-blockade in pheochromocytoma can precipitate hypertensive crisis.^10,30
• Benzodiazepines: sedation, falls and fractures in older adults, respiratory depression in COPD or sleep apnea, cognitive impairment, dependence and withdrawal seizures.³¹
• Hydroxyzine: sedation, anticholinergic burden, QT prolongation at higher doses.²⁹

Diagnostic and management hazards

• Premature anxiolysis without workup risks masking thyroid storm, pheochromocytoma crisis, evolving cardiac ischemia, or pulmonary embolism.^6,10,13
• Reflexive psychiatric labeling delays disease-directed treatment and erodes patient trust.⁶
• Polypharmacy is common in medically ill patients and amplifies drug-drug interaction risk.⁸

Limitations of the evidence base

• Few RCTs specifically enroll patients with DSM-5-TR Anxiety Disorder Due to Another Medical Condition; most evidence is extrapolated.^2,29
• Heterogeneity of underlying conditions limits generalizability; trials in COPD anxiety, post-MI anxiety, and oncologic anxiety populations are not interchangeable.³³
• Short follow-up in most intervention studies and limited data on long-term functional outcomes.³³

Disease drivers and tolerability profiles shift across the lifespan and across comorbid contexts. Tailor accordingly.^6,38

Pediatric

• Hyperthyroidism, asthma, congenital heart disease, and migraine are among the medical drivers of anxiety described across age groups, including children and adolescents.^4-6
• SSRIs (fluoxetine, sertraline, escitalopram) carry FDA boxed warnings for suicidality in pediatric populations and require informed consent and monitoring.³⁹
• Benzodiazepines are generally avoided due to paradoxical disinhibition and dependence risk.³⁹

Geriatric

• New-onset anxiety in older adults is more likely to have a medical or medication driver than in younger patients.⁶
• Avoid benzodiazepines per Beers criteria; prefer SSRIs, SNRIs, or buspirone with cautious titration.⁴⁰
• Watch for SIADH and hyponatremia with SSRIs/SNRIs; check sodium 2-4 weeks after initiation in higher-risk patients.³⁷

Perinatal

• Hyperthyroidism (including transient gestational thyrotoxicosis), hypoglycemia in pregestational diabetes, and pulmonary embolism (elevated risk in pregnancy and postpartum) are key considerations.^4,11,41
• SSRIs are generally compatible with pregnancy after individualized risk-benefit discussion; paroxetine is typically avoided due to teratogenicity concerns.⁴¹
• Benzodiazepines near term are associated with neonatal sedation and withdrawal.⁴¹

Comorbid medical illness

• Cardiac: avoid stimulants and sympathomimetics; SSRIs broadly safe, with sertraline particularly well-studied post-MI.⁴²
• Pulmonary: avoid benzodiazepines in advanced COPD and in patients with hypercapnia; combine pulmonary rehabilitation with CBT.⁵
• Hepatic and renal impairment: dose-adjust SSRIs/SNRIs and avoid agents with active metabolites that accumulate.^8-9

Comorbid substance use

• Alcohol and benzodiazepine withdrawal can mimic and exacerbate anxiety; manage withdrawal first.²³
• Stimulant and caffeine intake assessment and reduction are first-line.⁸
• Avoid benzodiazepine prescribing in active substance use disorder when possible.³¹

Cultural considerations

• Somatic idioms of distress vary across cultures; what presents as "chest pressure" or "heart pain" may reflect anxiety, cardiac disease, or both.⁴³
• Stigma around psychiatric diagnosis can amplify reluctance to accept anxiolytic treatment even when warranted; integrative explanations that include the medical driver often improve acceptance.^6,43

Prognosis tracks the trajectory of the underlying medical condition. When the driver is reversible, anxiety typically remits; when it is chronic, anxiety often persists and warrants ongoing management.^4-5

Course patterns

• Reversible drivers (hyperthyroidism corrected, pheochromocytoma resected, offending medication discontinued, hypoglycemia regimen adjusted): anxiety typically resolves within weeks to months.^4,10
• Chronic drivers (COPD, heart failure, Parkinson disease, multiple sclerosis): anxiety tends to be persistent, with course shaped by disease progression and rehabilitation.^5,17
• Episodic drivers (paroxysmal arrhythmia, complex partial seizures): anxiety is episodic and improves with control of the underlying paroxysmal event.^13,15

Outcomes data

• Anxiety in cardiac populations is associated with worse cardiac outcomes including increased mortality and rehospitalization, though causality is debated.⁴²
• Anxiety in COPD is associated with more frequent exacerbations and higher healthcare utilization.⁵
• Treatment of the underlying condition is the single most consistent predictor of symptomatic improvement.⁶

The acute risks are not the anxiety per se but the medical drivers behind it. The emergency triage is medical first, psychiatric second.^6,10,13

Medical emergencies presenting as anxiety

• Thyroid storm: fever, tachycardia, altered mental status, heart failure; mortality high without immediate treatment with antithyroid drugs, beta-blockade, iodine, and corticosteroids.⁴⁴
• Pheochromocytoma crisis: severe paroxysmal hypertension, headache, end-organ damage; alpha-blockade before any beta-blockade.¹⁰
• Pulmonary embolism: sudden dyspnea, tachycardia, chest pain, hypoxemia; consider in any acute anxiety with cardiopulmonary findings.¹³
• Acute coronary syndrome: chest discomfort with anxiety, particularly atypical presentations in women, older adults, and patients with diabetes.¹³
• Hypoglycemia: sudden anxiety with diaphoresis and tremor in patients on insulin or sulfonylureas; obtain glucose immediately.¹¹
• Anti-NMDA receptor encephalitis or other autoimmune encephalitides: subacute anxiety with psychosis, seizures, dyskinesias, autonomic instability.¹⁹

Psychiatric safety considerations

• Suicide risk assessment is part of every evaluation; anxiety, particularly when comorbid with depression and serious medical illness, elevates risk.⁴⁵
• Hospitalization is warranted when severe agitation, suicidal ideation with intent, or inability to manage the medical workup safely outpatient is present.^6,45
• Coordinate with the medical team; an anxious patient who refuses workup may need capacity assessment and ethical-legal consultation.³⁶

The category sits at a clinically useful but epistemically uncomfortable intersection of psychiatry and internal medicine. Several debates remain unresolved.^6,21

• Diagnostic threshold: distinguishing a direct physiologic cause from psychological reaction to medical illness can be clinically arbitrary, especially when both contribute. DSM-5-TR offers a framework but not a bright line.²¹
• Etiologic attribution: assigning causality to a medical condition often relies on clinical judgment and temporal association rather than mechanistic proof, particularly for conditions like irritable bowel syndrome, fibromyalgia, and chronic Lyme syndromes where bidirectional relationships are likely.^2,6
• Treatment evidence: the field lacks RCTs that specifically enroll patients diagnosed with Anxiety Disorder Due to Another Medical Condition; recommendations rest on extrapolation, expert consensus, and disease-specific anxiety literature.^2,29
• DSM-ICD divergence in the past: prior DSM editions included specifiers for symptom subtype ("with panic attacks," "with generalized anxiety," "with obsessive-compulsive symptoms") that DSM-5-TR no longer formally tracks for this category, complicating comparisons across older literature.²¹
• Cardiovascular anxiety and outcomes: whether treating anxiety in cardiac populations improves cardiac outcomes remains debated; ENRICHD and SADHART addressed depression more than anxiety, leaving the question partially open.⁴²
• Long COVID and post-acute infection syndromes: emerging evidence implicates persistent anxiety as part of post-acute sequelae, with unsettled mechanisms and evolving diagnostic frameworks.⁴⁶

• Anxiety Disorder Due to Another Medical Condition is coded 293.84 (F06.4) in DSM-5-TR.²¹
• The diagnosis requires evidence that the anxiety is the direct physiologic consequence of another medical condition, not a psychological reaction to illness.²¹
• New-onset anxiety after age 40 in a previously psychiatrically well patient should prompt a medical workup before psychiatric treatment.⁶
• Pheochromocytoma classically presents with the triad of paroxysmal hypertension, headache, and diaphoresis, with anxiety often prominent.¹⁰
• Beta-blocker monotherapy in pheochromocytoma can precipitate hypertensive crisis through unopposed alpha activity; alpha-blockade is given first.¹⁰
• Hyperthyroidism produces anxiety, tremor, tachycardia, weight loss, and heat intolerance, with TSH and free T4 the initial laboratory tests.⁴
• Plasma free metanephrines or 24-hour urinary metanephrines and catecholamines are the first-line tests for pheochromocytoma.¹⁰
• Complex partial seizures of temporal lobe origin can produce stereotyped ictal fear that mimics panic disorder; EEG and imaging are indicated when episodes are stereotyped or accompanied by post-event confusion.¹⁵
• Anti-NMDA receptor encephalitis classically presents in young women with subacute anxiety, psychosis, seizures, dyskinesias, and autonomic instability, often with an associated ovarian teratoma.¹⁹
• Hypoglycemia is a frequently missed cause of episodic anxiety in patients on insulin or sulfonylureas and is relieved by glucose administration.¹¹
• Beta-blockers are contraindicated as monotherapy in unstable asthma and decompensated heart failure and should be used cautiously in COPD.³⁰
• Benzodiazepines should be avoided in older adults per Beers criteria and in patients with respiratory failure or substance use disorders.^31,40
• Adjustment disorder with anxiety, not Anxiety Disorder Due to Another Medical Condition, is the correct diagnosis when anxiety arises as a psychological reaction to a serious medical diagnosis.²¹
• Pulmonary rehabilitation reduces dyspnea-related anxiety in COPD and is preferred over chronic benzodiazepine prescribing.⁵
• ICD-11 codes the equivalent construct as Secondary Anxiety Syndrome (6E63).²²

No external funding. No conflicts of interest declared. Peer-review status: pending.