29-year-old starting sertraline for moderate depression.
Asks: 'How long until it works, and what should I watch for?'
The most accurate framing?
Therapeutics · Psychiatry
Major depressive disorder
Therapeutic goals
- Remission, not response, and function, not just scores
- An honest timeline: benefit in weeks, side effects first
- A relationship that keeps the patient taking the medication long enough to judge it
Patient factors that steer the choice
- Prior response (personal and family): the best predictor available
- Sleep, appetite, and energy profile shaping agent choice
- Comorbid pain (SNRI overlap), anxiety (start low), pregnancy
- Interactions: serotonergic load, bleeding risk, QT
- Early-therapy safety monitoring, especially under 25
Major drug classes
Treatment approach
01Start an SSRI, framed properly
First-line for most; the counselling script (weeks to work, side effects fade, do not stop alone) is as important as the molecule.
02Reassess at 2-4 weeks
Early partial response predicts success; nothing at all by 4 adequate weeks prompts dose optimization or switch.
03Switch or augment deliberately
Within-class switch, cross-class switch (SNRI), or augmentation: each with its own washout and interaction arithmetic.
04Continue and taper on purpose
Months of continuation after remission; taper slowly, never during a crisis, and never by running out.
Monitoring
- Structured mood measures and safety at 2-4 weeks then regularly
- Early activation/suicidality window
- Sodium in older adults if symptomatic
- Discontinuation symptoms during any taper
Pearls
- The refill that never happens in week three is the commonest 'treatment failure'.
- Ask about OTC ibuprofen at the SSRI counter: bleeding risk stacks quietly.
Choose the drug
Last reviewed 2026-08-15 · Principle-level content; jurisdiction-specific recommendations live in the cited guidelines: CANMAT Depression Guidelines (current) · APA Practice Guideline for the Treatment of Patients with Major Depressive Disorder