Diagnosis & episode characterization #
Persistent depressed mood or loss of interest for at least 2 weeks, associated symptoms and clinically meaningful impairment support a major depressive episode. Establish onset, previous recovery and recurrence. The episode description alone does not distinguish unipolar from bipolar illness.
Document psychosis, psychomotor change, catatonic features, anxiety, seasonal or reproductive timing, and the effect on nutrition, self-care and employment. Use the classification adopted by the service; do not equate a PHQ-9 band with a diagnostic specifier.
Focused assessment #
Reconstruct the current episode and every previous treatment: drug, highest tolerated dose, time at that dose, missed doses, benefit, adverse effects and reason for stopping. Ask about past periods of increased activity with reduced need for sleep and obtain collateral where appropriate.
Assess self-harm thoughts, intent, preparation, access to means and recent changes directly. Examine cognitive complaints and psychomotor disturbance, rather than assuming that all concentration or memory problems are part of depression.
Differential diagnosis #
| Alternative | Discriminating clinical question |
|---|---|
| Bipolar depression | Has there been a distinct lifetime episode of elevation, increased activity or reduced need for sleep? |
| Medical or medication-related symptoms | Do onset and course track thyroid disease, other physical illness, or a medicine/substance exposure? |
| Grief, adjustment and comorbid anxiety | Clarify context, persistent anhedonia, functioning and coexisting syndromes; bereavement does not exclude an episode. |
Investigations with a clinical purpose #
| Finding / treatment context | Investigation | Purpose |
|---|---|---|
| Fatigue, systemic symptoms or suspected endocrine disease | Directed physical examination; thyroid testing and other tests guided by findings | Identify a contributor that changes the formulation. |
| Nutritional or neurological clues | B12 and other deficiency/infection tests according to history and examination | Avoid attributing reversible symptoms solely to depression. |
| Older age, diuretics, confusion or hyponatraemia susceptibility | Serum sodium when indicated | Establish or investigate a treatment-related electrolyte problem. |
| QT vulnerability or interacting medicines | ECG and relevant electrolytes | Evaluate medicine-specific cardiac risk. |
Treatment selection #
View treatment map
- Less severe episode
Discuss guided self-help, behavioural activation or CBT; antidepressants are not routinely the first option unless preferred.
- More severe nonpsychotic episode
Discuss antidepressant treatment and structured psychotherapy, including combined treatment. Match adverse-effect burden to comorbidity and preference.
- Psychotic depression
Specialist care; consider an antidepressant with an antipsychotic and monitor both symptom groups.
- Urgent response needed or severe treatment resistance
Consider ECT after an individualized benefit/risk and consent assessment, particularly with life-threatening poor intake.
| Clinical situation | Treatment approach |
|---|---|
| Less severe episode | Discuss guided self-help, behavioural activation or CBT; antidepressants are not routinely the first option unless preferred. |
| More severe nonpsychotic episode | Discuss antidepressant treatment and structured psychotherapy, including combined treatment. Match adverse-effect burden to comorbidity and preference. |
| Psychotic depression | Specialist care; consider an antidepressant with an antipsychotic and monitor both symptom groups. |
| Urgent response needed or severe treatment resistance | Consider ECT after an individualized benefit/risk and consent assessment, particularly with life-threatening poor intake. |
Doses & prescribing #
Each prescribing record identifies its population and source jurisdiction; international labeling does not establish Indian approval. The clinician selects treatment after assessment.
Sertraline
Major depressive disorder
Adults · Immediate-release tablets · Oral · United States product labeling
- Starting dose
- 50 mg once daily.
- Titration
- Increase by 25–50 mg/day no more often than weekly, according to response and tolerability.
- Treatment range / target
- 50–200 mg/day.
- Maximum / limits
- 200 mg/day.
- Trial & duration
- Assess response and tolerability during the acute trial; maintenance duration is addressed below.
- Monitoring
- Activation, suicidality, sexual/GI effects; sodium when clinically indicated.
- Population & organ-function adjustments
- Mild hepatic impairment: halve starting and maximum doses. Moderate/severe hepatic impairment: not recommended. No renal adjustment in the cited label.
- Important cautions
- Avoid MAOI combinations and pimozide; assess serotonergic combinations and bleeding risk.
Mirtazapine
Major depressive disorder
Adults · Immediate-release tablets · Oral · United States product labeling
- Starting dose
- 15 mg once daily, usually at bedtime.
- Titration
- Allow at least 1–2 weeks between dose changes.
- Treatment range / target
- 15–45 mg/day.
- Maximum / limits
- 45 mg/day.
- Trial & duration
- Continue according to response, remission and recurrence history; taper rather than abruptly stop.
- Monitoring
- Sedation, appetite, weight, metabolic effects and activation; fever/sore throat warrants assessment for blood dyscrasia.
- Population & organ-function adjustments
- Clearance is reduced in renal/hepatic impairment and older adults; dosage reduction may be necessary.
- Important cautions
- Avoid MAOIs; consider additive sedation, hyponatraemia, QT vulnerability and rare severe skin reactions.
Adequate trial & next steps #
NICE recommends reassessment when there is no response after 4 weeks at a recognized therapeutic antidepressant dose. This is a review point, not an automatic instruction to stop.
VA/DoD describes an adequate initial trial as 6–12 weeks overall, including 4–6 weeks at the maximum recommended or tolerated dose. Check diagnosis, adherence, comorbidity and psychosocial factors. Then discuss switching medication or psychotherapy, adding psychotherapy, or specialist augmentation; record why the selected next step fits the prior response.
Continuation & discontinuation #
Continue effective antidepressant treatment for at least 6 months after remission, with longer relapse prevention considered according to recurrence and residual symptoms. Review need and tolerability regularly.
Reduce doses in stages, adapting the pace to withdrawal symptoms, treatment duration and drug characteristics. Symptoms emerging soon after a reduction require distinction between withdrawal and recurrence; there is no universal taper schedule.
Special populations & comorbidity #
Pregnancy or breastfeeding requires a separate discussion of untreated illness, previous response and the selected drug’s exposure data. Avoid an abrupt switch solely because pregnancy is discovered. Severe perinatal illness needs coordinated specialist care.
Older adults need particular attention to falls, polypharmacy, sodium and cognitive change. Hepatic and renal impairment alter some antidepressant exposures; use the specific formulation’s adjustment instructions rather than class-wide assumptions.
Follow-up schedule #
| When | Review focus |
|---|---|
| Usually within 2 weeks of starting | Symptoms, adverse effects, adherence and emerging activation. |
| Within 1 week if aged 18–25 or suicide concern | Suicidality and the agreed support plan; subsequent frequency follows need. |
| During continuation | Residual symptoms, functioning, recurrence, medicine burden and the rationale for continued treatment. |
Clinical pitfalls #
An apparent increase in energy without recovery in mood requires reassessment, especially if sleep need falls or behavior becomes unusually driven. Do not treat activation as proof of antidepressant success.
Sedation or improved sleep alone is not remission. Conversely, persistent social or occupational difficulty may require rehabilitation and psychological work even after core mood symptoms improve.
Assessment tools #
Choose the instrument for its intended purpose; interpretation accompanies the linked tool.
Patient discussion #
Open a plain-language explanation
Depression can affect thinking, sleep, energy and relationships as well as mood. Assessment helps identify the pattern and agree care that fits the person.
Further reading #
References · 5
- NICE NG222 — depression management · United Kingdom · Checked 2026-10-26 · Supports: Treatment selection; Adequate trial & next steps; Continuation & discontinuation; Follow-up schedule
- VA/DoD 2022 — major depressive disorder, assessment and advanced care · United States · Checked 2026-10-26 · Supports: Focused assessment; Investigations with a clinical purpose; Treatment selection; Adequate trial & next steps
- NIMH — depression, diagnostic and treatment overview · United States · Checked 2026-10-26 · Supports: Diagnosis & episode characterization; Differential diagnosis; Special populations & comorbidity; Clinical pitfalls
- Sertraline tablets — product label, sections 2, 5 and 8 · United States · Checked 2026-10-26 · Supports: Investigations with a clinical purpose; Special populations & comorbidity; Clinical pitfalls; Sertraline — Major depressive disorder (Immediate-release tablets)
- Mirtazapine tablets — product label, sections 2, 5 and 8 · United States · Checked 2026-10-26 · Supports: Investigations with a clinical purpose; Special populations & comorbidity; Mirtazapine — Major depressive disorder (Immediate-release tablets)