SSRIs are the most prescribed antidepressants worldwide. If you're considering medication for depression or anxiety, here's what you need to know.
How SSRIs Work
SSRIs (Selective Serotonin Reuptake Inhibitors) increase serotonin levels in the brain by blocking its reabsorption. This doesn't 'fix' a 'chemical imbalance'—the reality is more complex—but it does help regulate mood, anxiety, and other symptoms for many people.
The SSRIs Available
- Escitalopram (Lexapro) - Often first-line, fewest drug interactions
- Sertraline (Zoloft) - Good for anxiety, safe in pregnancy
- Fluoxetine (Prozac) - Long half-life, good for those who miss doses
- Paroxetine (Paxil) - Effective but more side effects, harder to stop
- Citalopram (Celexa) - Similar to Lexapro, dose-limited due to heart effects
- Fluvoxamine (Luvox) - Often used for OCD
Which SSRI Is Best?
A major meta-analysis found escitalopram and sertraline had the best balance of efficacy and tolerability among 21 antidepressants.
Source: Cipriani et al., The Lancet, 2018That said, individual response varies enormously. The 'best' SSRI is the one that works for you with acceptable side effects.
What to Expect When Starting
Week 1-2
- Side effects often peak (nausea, headache, jitteriness)
- Mood may not improve yet
- Sleep and appetite may change
- Anxiety may temporarily increase
Week 2-4
- Side effects usually diminish
- Energy and sleep often improve first
- Mood improvement begins
- Full effect not yet reached
Week 4-8
- Full antidepressant effect typically reached
- If no improvement by week 6-8, discuss adjustments
- Side effects that remain are likely permanent
Common Side Effects
- Sexual dysfunction (30-50%) - reduced libido, difficulty with orgasm
- Weight changes (usually modest gain)
- GI upset (nausea, diarrhea) - usually temporary
- Insomnia or drowsiness
- Emotional blunting (feeling 'flat')
- Increased sweating
Stopping SSRIs Safely
Discontinuation symptoms include: dizziness, 'brain zaps,' flu-like feelings, irritability, insomnia. These are not addiction—they're your brain readjusting.
The Bottom Line
SSRIs help many people with depression and anxiety. They're not happy pills and they're not without downsides. But for moderate-to-severe symptoms, medication plus therapy is often the most effective approach.