Antidepressants – what to expect in the first weeks
The side effects come first and the benefit comes later, which is why so many people stop in week two. What actually happens, and when to call.
The timing is the whole problem
Antidepressants take two to six weeks to produce a meaningful improvement in mood. Side effects, when they occur, usually appear in the first days. So the ordinary experience is: feel somewhat worse, then neutral, then better — in that order.
Nobody warns people about this often enough, and it is the single commonest reason a treatment that would have worked gets abandoned in week two.
- Early and usually temporary: nausea, headache, disturbed sleep, jitteriness, more anxiety at first, appetite changes.
- These typically settle within one to two weeks.
- Often the first sign of benefit is sleeping better or having a little more energy — before mood itself lifts.
- Other people frequently notice the improvement before you do.
What to know before starting
Commonly prescribed in South Africa:
Fluoxetine — Prozac, Lorien, Adco-Fluoxetine, Nuzak
Major depressive disorder; anxiety disorders; PTSD; OCD; bulimia nervosa
Sertraline — Zoloft, Serdep, Adco-Sertraline, Lustral
Major depressive disorder; OCD; PTSD; social anxiety disorder; panic disorder
Escitalopram — Cipralex, Lexamil, Adco-Escitalopram, Ecytara
Major depressive disorder; generalised anxiety disorder; social anxiety disorder; panic disorder
Citalopram — Cipramil, Adco-Citalopram
Major depressive disorder; panic disorder
Venlafaxine — Efexor, Efexor XR, Venlor XR, Sandoz Venlafaxine
Major depressive disorder; generalised anxiety disorder; social anxiety disorder; neuropathic pain
Mirtazapine — Remeron, Mirteron
Major depression (especially with insomnia, poor appetite, anxiety)
Amitriptyline — Trepiline, Adco-Amitriptyline, Laroxyl, Elavil
Depression; neuropathic pain; migraine prophylaxis; insomnia (low dose)
- Ask what this one is expected to help, and how long before you should expect it.
- Ask what to do if a dose is missed, and when to come back.
- Take it at the same time daily; whether morning or night depends on whether it makes you drowsy or wakeful.
- Tell the prescriber every other medicine you take, including anything herbal — St John's wort in particular interacts dangerously with several antidepressants and with HIV medicines.
- Do not drink heavily on them; alcohol worsens depression and amplifies drowsiness.
- Expect a review within a few weeks rather than a repeat script and silence.
Things people are not told
- Sexual side effects are common, frequently persistent, and consistently under-discussed. They are a legitimate reason to switch — say so rather than quietly stopping.
- Weight change varies by medicine, and some are far more likely to cause it than others.
- It usually takes trying more than one to find the right fit. A first one not working is normal and not a sign that nothing will.
- They are not addictive in the sense that sedatives are, but stopping abruptly causes discontinuation symptoms — dizziness, electric-shock sensations, flu-like feelings, irritability. They must be tapered.
- Treatment usually continues for at least six months after you feel well, because stopping at the point of feeling better is strongly associated with relapse.
When to contact someone urgently
Medication is one part of treatment. Talking therapy has comparable evidence for mild to moderate depression and better long-term protection against relapse, and the combination outperforms either alone.
Common questions
- Will antidepressants change my personality?
- They are not meant to, and most people describe feeling like themselves again rather than different. Some report emotional blunting — a flatness across both good and bad feelings — which is worth reporting, as it often responds to a dose change or a switch.
- Are they addictive?
- They do not cause craving or dose escalation the way addictive drugs do. They do cause discontinuation symptoms if stopped abruptly, which is a different thing and is managed by tapering.
- How long will I need to take them?
- Usually at least six months after feeling well for a first episode, and longer for recurrent depression. It is a decision to make with your prescriber based on your history, not a fixed period.
Sources
- Mental health support and crisis resourcesSouth African Depression and Anxiety Group (SADAG)
- National Mental Health Policy Framework and Strategic PlanNational Department of Health, South Africa
- Primary Healthcare Standard Treatment Guidelines and Essential Medicines ListNational Department of Health, South Africa
Last reviewed 4 August 2026.