The timing of a drug’s antidepressant effects depends on many factors including the patient’s symptoms, biological individuality, and life stressors. Overall, a person can expect an antidepressant to work anywhere from four to eight weeks after the first dose.1 Some may notice wanted differences much sooner, while others will never note the desired effects.
What Are Antidepressants & How Do They Work?
Antidepressants are a large and diverse group of medications for depression that aim to reduce the signs and symptoms of any depressive disorder. The goal of an antidepressant is to peel away the effects of depression, so the person will begin to think, feel, and behave in ways that are no longer influenced by the condition, and they require a prescription.2
There are many types of antidepressants, many of which act differently on the body and the brain. The main types of antidepressants are:3
- Selective serotonin reuptake inhibitors (SSRIs). These medications work by systematically blocking neurons’ ability to reabsorb serotonin, so more of the wanted neurotransmitter is available to neighboring neurons. Some SSRI options include fluoxetine (Prozac), paroxetine (Paxil), sertraline (Zoloft), citalopram (Celexa) and escitalopram (Lexapro).
- Serotonin and norepinephrine reuptake inhibitors (SNRIs). Rather than only blocking the reabsorption of serotonin, SNRIs impact norepinephrine as well. SNRIs include duloxetine (Cymbalta), venlafaxine (Effexor), desvenlafaxine (Pristiq) and levomilnacipran (Fetzima).
- Atypical antidepressants. These drugs are a group of medications that do not work like SSRIs or SNRIs, but still have impact on the serotonin and norepinephrine systems. Trazodone, vortioxetine (Trintellix), vilazodone (Viibryd) and bupropion (Wellbutrin) are examples of atypical antidepressants.
Additionally, there are some older antidepressants that are used less often due to a greater risk of severe side effects. They are as effective in the treatment of depression. These antidepressant classes include:1
- Tricyclic antidepressants (TCAs) like imipramine (Tofranil), nortriptyline (Pamelor), amitriptyline, and doxepin.
- Tetracyclics like mirtazapine (Remeron) and maprotiline (Ludiomil).
- Monoamine oxidase inhibitors (MAOIs) like tranylcypromine (Parnate), phenelzine (Nardil) and isocarboxazid (Marplan).
Antidepressants can treat much more than major depressive disorder or other types of depression. Prescribers may recommend many antidepressants for anxiety, OCD, chronic pain, or sleep problems.1
*These medications have a black box warning, the most serious warning from the FDA for the risk of suicidal thoughts and behaviors in certain people. Before starting any of these medications, you should talk with your doctor about these risks.
Do Antidepressants Work Immediately?
Experts in the field commonly believe that antidepressants do not work immediately. Instead, they need a period of about four to six weeks to begin producing the desired result.1,2,3
Another school of thought states that antidepressants do work immediately, but the person will not be able to notice the early differences most of the time. Even from the first day someone takes an antidepressant, the medication is active in the brain. Researchers have found that some patients have found some antidepressant effects even a few hours after using medications.4
It is likely that both schools of thought have some merit. Antidepressants work in different manners at the neurotransmitter level and this may explain why effects can be seen in different timetables.
How Long Does It Take for Antidepressants to Work?
When starting a new medication, depression symptoms could alleviate in a matter of days, weeks, or months. In the more undesirable situations, they may never get better with that medication, and the person will have to trial others to get the wanted results.
Farrokh Alemi, PhD, Professor at George Mason University explains, “Symptom remission is usually defined as 50% reduction in symptoms of depression on the Hamilton scale. However, it’s unclear which symptom (if any) gets resolved first.”
Here is a general timeline outlining when you might expect to see results from antidepressants: 1,4,5,6
- 1 Day – On the first day of taking an antidepressant medication, most people will feel nothing at all. Some will notice side effects like nausea or vomiting that could be mild.
- 1 Week – One week in, people are more likely to note some other side effects like sleeping problems, diarrhea, dry mouth, and sexual problems. The patient may not see any desired effects yet.
- 2 Weeks – After 14 days of treatment, people may see their initial side effects dissipate. They may notice some changes in their symptoms like changing energy levels or improving moods, or other people may see the differences first.
- 1 Month – When someone completes their first month of treatment more significant symptom reduction could occur. They might be inspired and more motivated.
- 3 Months – At 90 days into treatment, the full effects of the antidepressant will be active, so if the targeted symptoms are low, they should stay low. Three months in, people may also notice some weight gain, which could be a side effect or a sign that one’s appetite has returned.
- 6 Months – Nothing new is likely at six months, but if symptoms remain well-treated and this is the person’s first bout of depression, the prescriber could consider ending the medication.
- 1 Year – Just like at the six month mark, no new changes are expected at one year. It is another good opportunity to reevaluate the treatment to see if the plan should be adjusted or left unchanged.
- After 1 Year – The typical length of treatment with an antidepressant is one year, but many people use them longer. Some may feel like the medication has lost its effectiveness over time, but many could remain on the same dose for long periods.
This is a typical timeline, but there are always exceptions to the rule. People should always stay patient, be alert, and maintain communication with their prescriber to ensure safety.
Do Any Antidepressants Work Quicker than Others?
Researchers seeking better ways to treat depression are always looking for medications that work quicker in the body. Finding medications that have a rapid onset of antidepressant action (ROAA) is a worthwhile pursuit.
Some medications that might work faster than others include:5
- Escitalopram (Lexapro) and citalopram (Celexa) show decreased symptoms as early as two weeks into treatment.
- Olanzapine – Fluoxetine Combination. By combining fluoxetine (Prozac) with an antipsychotic medication, olanzapine (Zyprexa), patients could report relief within two weeks. This is not likely a medication that would be used as a first line treatment for mild or moderate cases of depression due to its higher side effect burden.
- Mirtazapine (Remeron). Compared to SSRIs, Remeron helped improve sleep, anxiety, and movement issues during the first two weeks of treatment.
One encouraging treatment with a ROAA is esketamine. Esketamine (Spravato) can help people feel better after just a single treatment. A patient is likely to report lower symptoms within two hours with results lasting as long as two week.5 Rather than a pill you take, esketamine is given as a nasal spray or IV invulsion. At this time, esketamine has to be administered in a physician’s office.
Researchers and clinicians continue seeking the best ways to manage depression. For this reason, they experiment with brain stimulation, like transcranial magnetic stimulation (TMS)) and (electroconvulsive therapy (ECT)), sleep deprivation, and hormone changes.5 Depending on the patient’s symptoms, these treatments may be viable.
*These medications have a black box warning, the most serious warning from the FDA for the risk of suicidal thoughts and behaviors in certain people. Before starting any of these medications, you should talk with your doctor about these risks.
When to Expect Initial Improvement When Starting Antidepressants
As soon as one starts taking their medication, they should increase their awareness to notice any changes, including side effects or desired results. They should make their loved ones aware of their antidepressant, so that their friends and family can pay attention to any differences as well.
Some signs your antidepressants have started working may include:7
- Decreased feeling of hopelessness
- Better mood and irritability levels
- More balanced sleep and appetite
- More focus and better concentration
- Increased self-worth
- Fewer thoughts of self-harm and a decrease in suicidal ideation
- Higher energy and motivation
If all goes well, a person can expect these results between a few weeks and a few months after starting the medication.
When to Expect Maximum Benefits from Antidepressants
The maximum benefit from a medication is expected by two months of use. At that point, the full impact of the antidepressant will be experienced.
If a person is still not happy with the result, the treatment provider could decide to raise the dose, change the medication, or add another medication to boost the effects. The total time needed to find the best medication and the best dose can sometimes take months or years, so patience is always needed.
In fact, Alemi adds, “The majority of patients who receive antidepressants for the first time do not benefit from these medications.” He also notes that if this is the case, “You should not make sudden changes in medications or stop taking a medication unless advised by your clinician that it is safe to do so.”
Side Effects of Antidepressants
Some people experience side effects before depression relief, and many will feel no unwanted effects at all. Some side effects will quickly fade after a few days, and others will persist. Whatever the case, people should always consult with their prescriber about their effects and side effects of the antidepressant. Remember, the effects of depression could be much greater than the side effects of medication.1
Some common, early side effects of antidepressants include:1,3
- Nausea and vomiting
- Weight gain
- Diarrhea
- Being unable to fall asleep
- Sexual problems, like lower sexual interest and an inability to have sex
- Dry mouth
- Headaches
The side effects are often mild and tend to disappear as the patient’s body adapts.3 Younger people may experience some more troubling side effects of antidepressants.
Those under the age of 25 may notice increased depression and thoughts of suicide in the days or weeks after starting a new antidepressant.1 If you or someone you love is experiencing these troubling side effects, seek emergency medical services immediately or call 9-1-1.
What Causes Variability in Individual Response Time?
Much of antidepressant use is a mystery. No one is exactly sure how antidepressants work, why they don’t work for some people, and why they work slower in some than others.
In the simplest terms, the ways a person’s body absorbs and processes the medication will dictate the speed and level of effect. A person may not be able to change this, but exploring options with pharmacogenetic testing may offer insights.
How to Get the Most Out of Your Antidepressant Medication
Effective treatment for depression is multifaceted. If someone wants the best results, they will need to follow through with new routines, lifestyle changes, and all recommendations.
Alemi states that first and foremost, you should “Begin by making sure that you are taking the right medication. The Health Informatics Program of George Mason University has created a free site to help individuals learn more about potential antidepressants that could be right for them.” This should always be discussed with a prescribing doctor, but may be helpful for some.
Additionally, Alemi adds two other ways to make sure you’re getting the most out of your antidepressants; “Make sure your medication consistently and do not stop until passage of time or the medications lead to remission of symptoms. Then exercise. Exercise has been shown to be as effective as antidepressants for some patients.”
Some additional ways to ensure you’re getting the most out of your antidepressant medication include:3
- Stay patient and realize it will take some time for your body to feel the full results of the medication
- Take the correct dose of your medication around the same time each day
- The side effects may get better over time, so wait out the mild symptoms
- Talk about dose or medication changes with your prescriber to know what the next step is
- Start or increase therapy and try using options like cognitive behavioral therapy (CBT) for depression
- Avoid alcohol and other drugs while using your antidepressant to avoid distorting the results
- Boost your physical health with better diet, exercise, and sleep routines
You can take all the right steps and your antidepressant may not work well for you. It doesn’t mean there is anything wrong with you. It only means that you have not found your best match yet.
How Long Should You Take Antidepressants?
You should plan to take a new antidepressant for at least two month to study the effects and wanted results. You may only stop before this time if distressing or dangerous side effects emerge, and you should always consult with your doctor prior to doing so.
The duration of treatment will last at least six months and could go on indefinitely if you feel happy with the outcomes. Always discuss possible medication changes with your prescriber to understand the risks and benefits of changes.1
When Antidepressants Are Prescribed for Other Issues
Many people will use antidepressants to address depression, anxiety, or a combination of depression and anxiety. Whether you are using the medication for anxiety, for depression, or for other needs, the timeline will be consistent. Most effects will be noted between four to six weeks after the first dose.
Questions to Ask Your Health Team About Antidepressants
You never want to take medication without a good understanding of what it is and how it works in your system. Having this basic information can help make you aware of the risks and perceptive of any changes.
Questions to ask your care team about depression treatment and antidepressants include:1,3
- How do you know which antidepressant is right for me?
- How long will it take to work?
- What changes can I expect and what happens if I don’t notice any changes?
- What common side effects should I look out for?
- Can I mix different medications?
- Can I use alcohol or other drugs with this medication?
- What happens if I miss a dose?
- How much will this drug cost?
- Can I use this medication if I am pregnant or breastfeeding?
Asking questions and listening intently is always helpful, but your prescriber might not know all the answers. The science of antidepressants is not exact, and one of the most important and helpful questions to ask, Alemi says, is, “What is the evidence that this medication will work for me.”
Final Thoughts
Seeing immediate improvement in your symptoms from an antidepressant is rare, but be patient and aware of your condition to study the changes. Even if the process takes some trial and error, the benefits of an antidepressant could be life-changing.
