Psychosocial, Behavioral & Cognitive · Topic 4 of 7

Depression & Anxiety in Acute Illness

Psychosocial · mood and anxiety disorders

Depression & Anxiety in Acute Illness

Screen, exclude medical mimics, then treat: an SSRI is first line — sertraline is safe after MI — and never stop a home antidepressant abruptly.

Key numbers

Major depression: 5 symptoms for 2 weeks≥ 5 sx for ≥ 2 wk

Citalopram max 20 mg after age 60≤ 20 mg if > 60 y

01 · Defined byMajor depression: 5 symptoms for 2 weeks

Major depressive disorder = 5 or more DSM-5-TR symptoms nearly every day for at least 2 weeks, one being depressed mood or anhedonia, causing impairment and not explained by a substance or medical condition.

02 · GiveSSRI first line; sertraline is safe post-MI

An SSRI is the usual first-line antidepressant; sertraline proved safe and effective for depression after acute MI or unstable angina (SADHART), and SSRIs have few anticholinergic or cardiac conduction effects.

03 · The ruleNever stop an SSRI abruptly

Abruptly stopping an SSRI or SNRI causes discontinuation syndrome — nausea, chills, myalgia, dizziness, anxiety, irritability, insomnia; taper about 25% per week (fluoxetine, with its long half-life, causes it least).

Causes & risk factors

Why it happens

Exclude medical and drug causes first must knowExclude medical causes of depressive symptoms: hypothyroidism, Parkinson disease, stroke, cancer, and drugs such as corticosteroids, some beta-blockers and interferon; check CBC, electrolytes, TSH, vitamin B12 and folate.

Diagnosis & monitoring

Work-up

Check sodium when starting SSRIs in older adultsSSRIs, SNRIs, mirtazapine and tricyclics can cause SIADH and hyponatremia in older adults — monitor sodium closely when starting or changing the dose (AGS Beers 2023).

Ask about suicide when treating depressionAsk every depressed patient about suicidal thoughts — asking does not plant the idea; antidepressants carry a boxed warning for increased suicidal thinking at age 24 and younger, so monitor closely early in treatment.

Acute stress disorder: 3 days to 1 monthAcute stress disorder is diagnosed 3 days to 1 month after trauma; PTSD needs symptoms lasting at least 1 month. Use trauma-focused CBT; no drug routinely prevents PTSD, and prolonged benzodiazepines slow recovery.

Management

Orders

Screen for depression with the PHQ must knowUSPSTF recommends depression screening for all adults, including older and pregnant or postpartum adults (grade B), with a tool such as the PHQ; a positive screen needs a diagnostic interview, not treatment by score alone.

Response takes weeks; continue 6–12 monthsAntidepressant response usually begins in 2–3 weeks (up to 8); after remission continue for 6–12 months (longer for recurrent or severe episodes) to prevent relapse, then taper.

Citalopram max 20 mg after age 60Citalopram prolongs the QT interval dose-dependently: maximum 40 mg daily, and 20 mg daily for patients over 60, with hepatic impairment or CYP2C19 poor metabolizers; avoid with long QT, bradycardia or hypokalemia.

Mirtazapine sedates and adds weightMirtazapine causes sedation and weight gain, has fewer sexual adverse effects than SSRIs, no cardiac adverse effects and minimal hepatic drug interactions.

Benzodiazepines short term only for anxietyFor generalized anxiety, SSRIs or SNRIs (e.g., escitalopram, venlafaxine) are preferred and work in 3–6 weeks; benzodiazepines give immediate relief but only short term, and older adults should avoid them (falls, delirium).

PTSD: trauma-focused CBT, SSRIs, prazosinPTSD is treated with trauma-focused cognitive-behavioral therapy; SSRIs improve symptoms and prazosin reduces trauma nightmares. PTSD may begin months or years after the trauma.

Red flags & don'ts

Avoid harm

SSRIs plus antithrombotics raise bleeding risk interactionSSRIs increase bleeding risk when combined with aspirin, other NSAIDs, anticoagulants or other drugs that affect coagulation — weigh this in patients on antithrombotic therapy.

No SSRI with linezolid or methylene blue interactionSSRIs are contraindicated with MAOIs — including linezolid and IV methylene blue — or within 14 days of one, because of serotonin syndrome.

Avoid tricyclics in heart disease avoidTricyclic antidepressants are contraindicated in coronary artery disease and certain arrhythmias, are anticholinergic in older adults and are lethal in overdose — rarely a good choice in medically ill patients.

Acute stress disorder or PTSD?

Commonly confused

Timing after the trauma	3 days to 1 month
First-line treatment	Trauma-focused CBT
Medication	No routine drug; prolonged benzodiazepines slow recovery
Course	Can evolve into PTSD

Commonly confused

Tell apart

Panic: exclude ACS, arrhythmia and hyperthyroidismPanic disorder is diagnosed only after medical causes such as acute coronary syndrome, arrhythmia and hyperthyroidism are excluded; treat with an SSRI or other antidepressant plus CBT, with a benzodiazepine as a short bridge.

More detail

Reference

Show 4 reference facts

USPSTF recommends screening adults 64 or younger for anxiety disorders (grade B); evidence is insufficient for adults 65 or older.

Generalized anxiety disorder = excessive, hard-to-control worry about many matters on more days than not for at least 6 months, with 3 or more symptoms such as restlessness, fatigue, poor concentration or insomnia.

IV ketamine and intranasal esketamine act within hours; esketamine is FDA-approved for treatment-resistant depression (alone or with an oral antidepressant) and, with an oral antidepressant, for major depression with acute suicidal ideation or behavior.

Depression is associated with higher risk of cardiovascular disease, myocardial infarction and stroke, possibly through inflammatory cytokines, procoagulant factors and reduced heart rate variability.

Pearl

Rule out the thyroid, the steroids and the heart before you call it depression or panic.

Sources · Merck Manual Professional — Depressive Disorders · Merck Manual Professional — Medications for Treatment of Depression · USPSTF. Screening for Depression and Suicide Risk in Adults: Recommendation Statement. JAMA 2023;329:2057–2067 · USPSTF. Screening for Anxiety Disorders in Adults: Recommendation Statement. JAMA 2023;329:2163–2170 · Citalopram tablets prescribing information (dosage §2.1–2.3, contraindications, QT warning) — DailyMed · Glassman AH et al. Sertraline treatment of major depression in patients with acute MI or unstable angina (SADHART). JAMA 2002;288:701–709 · Merck Manual Professional — Posttraumatic Stress Disorder (PTSD) · Merck Manual Professional — Panic Attacks and Panic Disorder · Merck Manual Professional — Generalized Anxiety Disorder · Merck Manual Professional — Acute Stress Disorder · American Geriatrics Society 2023 Updated AGS Beers Criteria (Table 2 benzodiazepines; Table 4 SIADH/hyponatremia). J Am Geriatr Soc 2023;71:2052–2081 · Merck Manual Professional — Suicidal Behavior · Spravato (esketamine) nasal spray prescribing information — indications, REMS, boxed warning — DailyMed · Starter sheet built from the verified AGACNP fact map (facts reviewed 2026-10-15).