How Long Do Antidepressants Take to Work? A Realistic Week-by-Week Timeline
Updated: 5 days ago
Written by the Prescribed Wellness Psychiatry team · Medically reviewed by Veronica Sanchez, MD · Updated October 2026
Most antidepressants take four to eight weeks to work. According to the National Institute of Mental Health, sleep, appetite, energy, and concentration often improve before mood lifts. So the first sign that a medication is working is usually not feeling happy. It is sleeping through the night, or eating again, or getting through an afternoon without running out of gas.
That gap between starting a medication and feeling better is the hardest part of treatment, and it is where most people quit. Knowing what is supposed to happen, and when, makes the wait easier to sit through. Here is the honest version of the timeline.
Key takeaways✓ Most antidepressants take four to eight weeks to work, per the National Institute of Mental Health. ✓ Physical symptoms — sleep, appetite, energy, concentration — usually improve before mood does. ✓ Side effects often show up in the first week or two, before any benefit, and many ease with time. ✓ In the NIMH STAR*D study, about a third of people reached full remission on the first medication they tried, and it took an average of nearly seven weeks. ✓ If nothing at all has shifted after four to six weeks, that is a reason to check in with your prescriber — not a reason to stop on your own. |
What happens in the first two weeks?
In the first two weeks, side effects usually arrive before benefits do. The National Institute of Mental Health lists upset stomach, headache, and sexual side effects as common with SSRIs and other antidepressants, and notes that these "are generally mild and tend to go away with time." Mayo Clinic puts it the same way: many side effects fade after the first few weeks.
This ordering is backwards from what anyone would want, and it is the single most common reason people stop a medication early. Feeling queasy on day four is not a sign that the medication is wrong for you. It is a sign that your body is adjusting to it.
Some people do notice small changes in this window. Research suggests those early changes matter. A meta-analysis of 6,562 patients by Thase, Szegedi and colleagues, published in the Journal of Clinical Psychiatry in 2009, found that improvement in the first two weeks predicted later response with high sensitivity — and that a complete lack of early improvement was a strong signal that the current plan might need adjusting sooner than psychiatrists traditionally assumed.
What that research does not mean: that feeling nothing at two weeks predicts failure. The same analysis found that early improvement was much better at ruling outcomes out than ruling them in. Plenty of people who feel nothing early still do well.
When should my mood actually lift?
For most people, the four-to-eight-week window is where mood change shows up. The National Institute of Mental Health gives four to eight weeks as the standard range, and the 2022 VA/DoD clinical practice guideline for major depressive disorder describes a minimum of four to six weeks of treatment before concluding that someone has had a partial response or no response at all.
The largest real-world study of this is STAR*D, run by the National Institute of Mental Health. In its first phase, it took participants an average of nearly six weeks to reach a "response" — meaningful improvement — and nearly seven weeks to reach "remission," meaning symptoms largely resolved.
Averages hide a lot. Some people feel different in ten days. Some need the full eight weeks and then some. We cannot predict in advance which one you will be, and any psychiatrist who tells you otherwise is guessing.
Do side effects mean the medication is working?
No. Side effects and benefit run on separate tracks. A medication can cause nausea in week one and do nothing for your mood, or cause almost no side effects and work well. One does not predict the other.
This matters because people sometimes read early side effects as proof that "something is happening" and hold on too long, or read the absence of side effects as proof that the dose is too low. Neither reading is reliable. What matters is whether your symptoms move over the four-to-eight-week window, and that is what your prescriber should be tracking with you.
The National Institute of Mental Health notes that people who are sensitive to side effects sometimes do better when the medication is started at a low dose and increased slowly, or taken at a different time of day. Those are conversations to have with your prescriber rather than adjustments to make on your own.
What does a realistic week-by-week timeline look like?
Timeframe | What is common | What it does not mean |
Days 1–7 | Side effects such as nausea, headache, or changes in sleep often show up first. | Early side effects do not predict whether the medication will end up working. |
Weeks 1–2 | Sleep, appetite, energy, or concentration may start to shift before mood does. | Feeling no different this early is normal, not failure. |
Weeks 2–4 | Some people notice a real change. Many do not yet. | A slow start does not mean the medication is wrong for you. |
Weeks 4–8 | This is the window where most of the benefit shows up. | If nothing has moved at all by now, it is a reason to talk with your prescriber. |
After 8 weeks | Benefit can keep building for people who are already improving. | Waiting indefinitely without a check-in is not the plan. |
What if nothing has changed after a month?
Tell your prescriber. Do not stop the medication on your own, and do not quietly wait another two months hoping something shifts.
The VA/DoD guideline treats four to six weeks as the point at which a partial or absent response should prompt a change in the treatment plan. That change is not always a new medication. It might be a dose adjustment, adding something alongside it, adding or changing therapy, or looking harder at sleep, alcohol, thyroid, or another medical issue sitting underneath the depression.
The VA/DoD guideline also recommends using a quantitative measure of depression severity to plan treatment and track progress, rather than relying on memory alone. That is worth knowing as a patient: "I think I'm a little better" is much harder to act on than a score you and your prescriber have both been watching.
What if the first antidepressant does not work?
It is common, and it is not the end of the road. In the NIMH STAR*D study, about a third of participants reached remission on the first medication, with another 10 to 15 percent improving without reaching full remission. That means most people needed something beyond the first try.
Mayo Clinic notes that if one SSRI does not work well, a different one may, because these medications differ in how strongly they act and how quickly the body clears them. Switching within a class is a real option, not a consolation prize.
Whether the next step is a different medication, a different dose, adding therapy, or something else depends on your history, your symptoms, what you have already tried, and what side effects you can live with. That decision belongs to you and your prescriber together. This article cannot make it for you.
How long do I stay on it once I feel better?
Longer than most people expect. The 2022 VA/DoD guideline recommends continuing antidepressants at the therapeutic dose for at least six months after symptoms remit, to lower the risk of relapse. Feeling better is the point at which the medication is working, not the point at which it has finished working.
Stopping matters as much as starting. FDA prescribing information for escitalopram, updated in 2025, instructs that the dose be reduced gradually rather than stopped abruptly whenever possible, and lists nausea, sweating, mood changes, irritability, dizziness, tremor, and anxiety among the reactions that can follow discontinuation. Mayo Clinic describes the same pattern with stopping suddenly or missing several doses.
None of that means the medication is addictive. It means your body adapts to it, and coming off is a process to plan with your prescriber rather than a decision to make on a bad Tuesday.
When should I call before my next appointment?
Sooner than you think. Call your prescriber if you feel noticeably worse, if you are more agitated or unable to sleep, or if side effects are bad enough that you are thinking about stopping.
There is one specific window worth knowing about. FDA prescribing information carries a boxed warning that antidepressants increased the risk of suicidal thoughts and behaviors in patients age 24 years and younger in short-term studies, and instructs that all patients taking antidepressants be closely monitored for clinical worsening and for the emergence of suicidal thoughts and behaviors. The National Institute of Mental Health notes this risk is highest in the first few weeks after starting a medication or after a dose change — which is exactly the window this article is about.
That is not a reason to avoid treatment. Untreated depression carries its own risk. It is a reason to stay in contact during the first weeks rather than disappearing until the next appointment.
If you are having thoughts of harming yourself, you do not need to wait for an appointment. Call or text 988, the Suicide and Crisis Lifeline, which is available 24 hours a day. If you are in immediate danger, call 911.
What does this look like at our practice?
At Prescribed Wellness Psychiatry, a first psychiatric evaluation is 50 minutes and follow-up visits are 25 minutes. That first visit is a long conversation about your history, your sleep, your energy, what changed, and what you have already tried — not a ten-minute prescription pad. Visits are available in person or by secure video anywhere in California, and in English or Spanish. You can switch between office visits and video visits.
Our office is at 3800 Barham Boulevard, Suite 416, at the Cahuenga Pass, with parking in the building. That puts us a few minutes from the Burbank and Universal lots, and a short drive whether you are coming from Toluca Lake, Studio City, or over the hill from Hollywood.
We accept Medicare for psychiatry. Medicare patients are seen in person in Los Angeles and by secure video anywhere in California, including Bakersfield and San Diego.
What is the next step?
If you are in the middle of the wait right now and wondering whether to keep going, that question is worth bringing to a prescriber rather than answering alone at 2 a.m. If you have never started, an evaluation is where the timeline begins.
You can request an appointment online, or call or text (626) 681-3729. Intake forms are sent before your visit, and what to bring and expect is on our current patients page. You can read more about Dr. Sanchez and her background, or, if attention and focus are part of the picture for you, our guide to how an adult ADHD evaluation works.
Frequently asked questions
How long do antidepressants take to work?
Most antidepressants take four to eight weeks to work, according to the National Institute of Mental Health. Sleep, appetite, energy, and concentration often improve before mood lifts. Some people notice changes sooner, and some need the full eight weeks or longer. Your prescriber should be tracking your symptoms with you across that window rather than waiting for one dramatic moment.
Is it normal to feel nothing after two weeks on an antidepressant?
Yes. Two weeks is early. A 2009 meta-analysis of 6,562 patients found that early improvement predicts later response, but also that its main value is ruling outcomes out rather than in — many people who feel nothing at two weeks still respond well. Feeling no different this early is not evidence that the medication has failed.
Do side effects mean my antidepressant is working?
No. Side effects and benefit are unrelated. Antidepressant side effects such as upset stomach, headache, and sexual side effects often appear in the first week or two, and the National Institute of Mental Health notes they are generally mild and tend to ease over time. A medication can cause side effects and not help, or help with almost no side effects.
What should I do if my antidepressant is not working after a month?
Talk to your prescriber rather than stopping on your own. The 2022 VA/DoD clinical practice guideline describes four to six weeks as the point at which a partial or absent response should prompt a change to the plan. That change might be a dose adjustment, a different medication, adding therapy, or looking for a medical issue underneath the depression.
How long do I have to stay on an antidepressant once it works?
The 2022 VA/DoD guideline recommends continuing an antidepressant at the therapeutic dose for at least six months after symptoms remit, in order to lower the risk of relapse. How long beyond that depends on your history and how many episodes you have had. That is a decision to make with your prescriber, not a fixed rule.
Can I stop an antidepressant suddenly if I feel better?
No — plan it with your prescriber. FDA prescribing information instructs that the dose be reduced gradually rather than stopped abruptly whenever possible, and lists nausea, sweating, mood changes, irritability, dizziness, tremor, and anxiety among reactions that can follow discontinuation. This does not mean antidepressants are addictive; it means your body adapts and coming off needs a plan.
Sources
National Institute of Mental Health. Mental Health Medications.
National Institute of Mental Health. Depression.
National Institute of Mental Health. STAR*D Study Level 1 Results.
Thase ME, Szegedi A, Jansen WT, et al. Early improvement in the first 2 weeks as a predictor of treatment outcome in patients with major depressive disorder: a meta-analysis including 6562 patients. Journal of Clinical Psychiatry. 2009;70(3):344–353.
U.S. Department of Veterans Affairs and U.S. Department of Defense. VA/DoD Clinical Practice Guideline for the Management of Major Depressive Disorder. 2022.
U.S. Food and Drug Administration. Escitalopram capsules prescribing information. 2025.
Mayo Clinic. Selective serotonin reuptake inhibitors (SSRIs).
Medical disclaimer: This article is for general educational purposes and does not constitute medical advice, diagnosis, or treatment, nor a guarantee of insurance coverage. Coverage rules and costs change and vary by plan; always verify your benefits. If you are in crisis or thinking about harming yourself, call or text 988 (Suicide & Crisis Lifeline) or call 911.
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