Executive summary
- Assessment: PHQ-9 score + Functional Impairment + Risk (Suicide/Self-harm).
- Mild (PHQ-9 <10): Do NOT start antidepressants routinely. offer Guided Self-Help or CBT.
- Mod/Severe (PHQ-9 ≥10): Combined approach (SSRI + High-intensity CBT) is most effective.
- Safety: Review 1-2 weeks after starting (increased anxiety/suicide risk in early phase).
Pharmacological Steps (Adults)
- Step 1: SSRI (First Line)
- Sertraline: Start 50mg od -> Titrate to 200mg (in 50mg steps every 3-4 weeks). Preferred in cardiac history.
- Citalopram: Start 20mg od -> Max 40mg (Max 20mg if age >65 or QT risk). Requires ECG if high dose/risk.
- Fluoxetine: Start 20mg od -> Max 60mg. (Long half-life: useful if adherence poor, but 4-week washout to switch).
- Step 2: Switch (No response after 4-6 weeks)
- Compliance check first.
- Switch to different SSRI (e.g., Sertraline to Escitalopram).
- OR Mirtazapine: Start 15mg or 30mg nocte -> Max 45mg. (Good for insomnia/poor appetite).
- Step 3: Escalation
- Venlafaxine (SNRI): Start 75mg XL -> Max 225mg XL (BP monitoring essential). usually specialist initiation or experienced GP.
Switching & Stopping
- Cross-tapering: usually needed when switching (e.g., halve dose of A, add low dose of B). *Except Fluoxetine -> others (needs washout).*
- Discontinuation: Taper over at least 4 weeks (months if long-term use) to avoid "brain zaps" and rebound.
Transparency
This page is an educational, clinician-written summary of publicly available NICE guidance intended for trained healthcare professionals. It uses original wording (not copied text) and should be used alongside the full NICE source, local pathways, and clinical judgement. Doses provided are for general reference; always check the BNF/SPC.