Depression in adults

Red Flags

Active suicidality, severe self-harm, or psychotic features — same-day mental health assessment under safeguarding pathway; admission if risk to life^[1]
Severe depression with psychomotor retardation, food/fluid refusal, or catatonia — admission and consideration of ECT^[1]
Bipolar features (prior mania/hypomania, family history, antidepressant-induced mood elevation) — switch to mood stabiliser; do not start antidepressant alone^[1]
Pregnancy or planning pregnancy on antidepressant — perinatal mental health and obstetric review^[1]

Severity-guided treatment selection^[1]
Mild: CBT, behavioural activation, structured self-help. Moderate–severe: combined antidepressant + psychological therapy. Severe with psychosis or risk: psychiatry / ECT consideration
Cognitive behavioural therapy or interpersonal therapy^[1]
12–20 sessions; equivalent to antidepressant in moderate depression at 12 months; lower relapse rate; combine with medication for severe
Continuation and maintenance phase^[1]
Continue antidepressant ≥6 months after first episode achieves remission; ≥1–2 years for second episode; lifelong for ≥3 episodes or severe relapse history
Treatment-resistant pathway^[1]
Failure of 2 adequate trials → augmentation (lithium, atypical antipsychotic, T3, second antidepressant) or switch class; consider ECT, esketamine, rTMS for refractory illness

Drug	Class	Adult	Paediatric	Notes
Escitalopram^[1]	SSRI	10 mg PO daily start, titrate to 10–20 mg/day	—	First-line; QTc warning at higher doses; relatively few drug interactions; review at 2–4 weeks, full effect 4–6 weeks
Sertraline^[1]	SSRI	50 mg PO daily start, titrate to 100–200 mg/day	—	First-line; activating, weight-neutral; counsel about initial activation and suicide warning <25 years
Mirtazapine^[1]	Tetracyclic antidepressant	15 mg PO night start, titrate to 30–45 mg night	—	Useful with insomnia, weight loss, comorbid anxiety; sedating at lower doses; weight gain; less sexual dysfunction than SSRIs
Venlafaxine extended-release^[1]	SNRI	75 mg PO daily start, titrate to 150–225 mg/day	—	Second-line if SSRI inadequate; monitor BP at higher doses; discontinuation syndrome — taper
Amitriptyline (TCA)^[1]	Tricyclic antidepressant	Start 25 mg PO night, titrate to 75–150 mg	—	Effective but anticholinergic, cardiotoxic in overdose; reserve for refractory or comorbid neuropathic pain/insomnia; ECG before higher dose
Lithium (augmentation)^[1]	Mood stabiliser	Start 400 mg PO daily, titrate to plasma 0.4–0.8 mmol/L	—	Augmentation in treatment-resistant depression; renal and thyroid function monitoring; teratogen
Olanzapine + fluoxetine combination (TRD or psychotic depression)^[1]	Atypical antipsychotic + SSRI	Olanzapine 5–10 mg PO + fluoxetine 20–40 mg PO daily	—	Treatment-resistant or psychotic depression; metabolic monitoring

Escitalopram^[1]

SSRI

First-line; QTc warning at higher doses; relatively few drug interactions; review at 2–4 weeks, full effect 4–6 weeks

Sertraline^[1]

SSRI

First-line; activating, weight-neutral; counsel about initial activation and suicide warning <25 years

Mirtazapine^[1]

Tetracyclic antidepressant

Useful with insomnia, weight loss, comorbid anxiety; sedating at lower doses; weight gain; less sexual dysfunction than SSRIs

Venlafaxine extended-release^[1]

SNRI

Second-line if SSRI inadequate; monitor BP at higher doses; discontinuation syndrome — taper

Amitriptyline (TCA)^[1]

Tricyclic antidepressant

Effective but anticholinergic, cardiotoxic in overdose; reserve for refractory or comorbid neuropathic pain/insomnia; ECG before higher dose

Lithium (augmentation)^[1]

Mood stabiliser

Augmentation in treatment-resistant depression; renal and thyroid function monitoring; teratogen

Olanzapine + fluoxetine combination (TRD or psychotic depression)^[1]

Atypical antipsychotic + SSRI

Treatment-resistant or psychotic depression; metabolic monitoring

Most antidepressants take 4–6 weeks for full effect; do not stop because of initial side effects without speaking to your prescriber^[1]
If suicidal thoughts emerge or worsen on starting an antidepressant — same-day medical review and crisis support^[1]
When stopping antidepressant — taper gradually over weeks to avoid discontinuation syndrome (flu-like symptoms, dizziness); never stop abruptly^[1]

Treatment-resistant depression after failure of two adequate antidepressant trialsSpecialist mental health team / mood disorder clinic^[1]
Severe depression with psychotic features, catatonia, or risk to lifeEmergency mental health and consideration of ECT^[1]
Bipolar features detected during assessmentPsychiatry for mood stabiliser initiation^[1]
Pregnancy or planning pregnancy on antidepressantPerinatal mental health for medication review^[1]

Diagnosis and stepwise pharmacological + psychological management of depressive disorder in adults.

1.Indian Psychiatric Society Clinical Practice Guidelines for Management of Depression (2023, Grover et al.) (2023)