Why is my anxiety worse on antidepressants? Here's what's actually happening
More anxiety after starting, raising or missing a dose is common, and the timing usually tells you why. Here's what each pattern means, how long it tends to last, and when it needs a call.
By Tanya Rybakova · Medically reviewed by Dr. Jason Tan , Consultant Psychiatrist · 2026-10-27 · 11 min read
Key takeaways A temporary rise in anxiety is a recognized effect of starting an antidepressant. It usually peaks in the first one to two weeks and settles as the body adjusts. When the anxiety started is the best clue to its cause: soon after starting, after a dose increase, a few weeks in, or after a missed or reduced dose each point to something different. Starting at a lower dose and increasing slowly can reduce early anxiety, which is why prescribers often do this for panic and anxiety disorders. A constant inner restlessness that makes it hard to sit still (akathisia) is not ordinary anxiety. Contact your prescriber promptly. Anxiety with thoughts of self-harm, signs of mania, or fever, sweating and muscle twitching needs urgent help. Talk to your prescriber before stopping or changing your dose. On this page
What timing tells you about anxiety on antidepressants Why can antidepressants make anxiety worse at first? How anxiety side effects differ by antidepressant Can a dose increase make anxiety worse? Why can anxiety come back a few weeks into treatment? Can a missed dose or tapering cause anxiety? Akathisia vs anxiety: how to tell them apart When does anxiety on antidepressants need urgent help? How can you manage anxiety when starting antidepressants? What to track when anxiety rises on antidepressants You started an antidepressant to feel less anxious. A week later, you feel more anxious than you did before: heart racing, a hum of dread, maybe a panic attack you didn't see coming. When anxiety gets worse on antidepressants, it's hard not to read that as proof the medication is wrong for you.
It often isn't. Anxiety that rises after starting, raising or missing a dose is one of the most common things people describe in the early weeks of treatment.
Not every rise in anxiety has the same cause, though, and a few need prompt attention. This guide goes through the main patterns, what's behind each one, and what you and your prescriber can do about it.
What timing tells you about anxiety on antidepressants
The single most useful question is when the anxiety started, and what changed just before it. Anxiety that begins in the first days of treatment, after a dose increase, a few weeks in, or after a missed dose usually has a different cause, and each pattern points to a different next step.
Common reasons anxiety rises on antidepressants. A general guide, not a way to diagnose yourself. When it started Most likely explanation What usually happens What to do Days to two weeks after starting Start-up activation ("jitteriness") Usually settles within one to two weeks, sometimes longer Tell your prescriber if it's hard to manage; a lower dose or slower increase may help Within days of a dose increase Start-up effects returning at the new dose Often settles again within a week or two Mention it at your review, or sooner if it's severe A few weeks in, after some improvement Ups and downs in early recovery, or the medicine not yet working fully Can be a short bad patch; the trend over several weeks matters more than one week Mention it at your review. Contact your prescriber sooner if it keeps getting worse, and seek help straight away if you have thoughts of self-harm Within a few days of a missed, late or reduced dose Withdrawal (discontinuation) symptoms Often eases when the usual dose is taken again Talk to your prescriber, especially if you're tapering Usually soon after starting or increasing a dose: you feel driven to keep moving and can't sit still Akathisia Doesn't usually resolve by pushing through Contact your prescriber promptly With very little need for sleep, racing thoughts or reckless energy Possible mania or a mixed state Needs assessment Seek urgent help With fever, heavy sweating, shivering or twitching, often after adding a medicine Possible serotonin syndrome Needs assessment Seek urgent help Gradually, over weeks to months, without a change in dose The medication isn't doing enough, or anxiety is returning Needs a review of the treatment plan Book a review rather than waiting it out
Why can antidepressants make anxiety worse at first?
Many people feel more anxious, restless or irritable in the first days of an antidepressant. Clinicians call it activation or jitteriness. NICE guidance for anxiety disorders names it directly: SSRIs and SNRIs can cause "increased anxiety, agitation and problems sleeping" when treatment starts.
How often it happens is hard to pin down. A systematic review found estimates ranging from 4% to 65% of people starting treatment, largely because studies measured it in different ways. The same review found no clear evidence that it was more common with SSRIs than with older antidepressants, or more common in people being treated for anxiety. Evidence on whether early jitteriness predicts how well the medicine eventually works is mixed.
Why does it happen? The exact mechanism isn't settled. Antidepressants change serotonin signaling within hours, but the brain's longer-term adjustment, the part linked to feeling better, takes weeks. In the meantime, the early increase in serotonin can stimulate some serotonin receptors linked to anxiety and arousal. As those receptors adapt, the jittery effect usually fades.
How long it lasts. For most people it is strongest in the first one to two weeks and then eases. It doesn't always follow a neat schedule. In one UK trial of people with depression, reports of agitation and sleep problems rose between weeks two and six before falling, even though side effects overall eased over the 12 weeks.
Why a low starting dose helps. A lower starting dose is thought to reduce the chance of start-up anxiety. For panic disorder, NICE advises starting an SSRI at a low dose and increasing it slowly to reduce side effects, including a temporary rise in anxiety. The UK prescribing information for escitalopram says the same: a low starting dose reduces the chance of an anxiety-provoking effect. If your prescriber started you low and is increasing slowly, this is usually why.
Anxiety is only one of the effects people notice early on. Our guide to side effects in the first two weeks covers the others and what tends to settle first.
How anxiety side effects differ by antidepressant
Start-up anxiety can happen with almost any antidepressant, but the pattern differs a little between them. More activating medicines, such as fluoxetine and bupropion, are more likely to cause early restlessness, and SNRIs can add physical signs like sweating. These are general tendencies, not predictions for you.
Can Zoloft (sertraline) make anxiety worse?
Yes, at first. A temporary rise in anxiety is a common early effect of sertraline, alongside nausea and loose stools. For panic disorder, social anxiety disorder and PTSD, it's usually started at 25 mg and increased after a week for this reason (Zoloft prescribing information ). For most people the extra anxiety eases within the first few weeks.
Can Lexapro (escitalopram) make anxiety worse or cause panic attacks at first?
It can. Some people notice more anxiety, and occasionally a panic attack, in the first week or two. Escitalopram is widely used for anxiety and panic, and the early rise usually settles. People with panic disorder are often started on a lower dose, such as 5 mg. In the UK, escitalopram is licensed for panic disorder; in the US it's prescribed for it off-label.
Can Prozac (fluoxetine) make anxiety worse?
Fluoxetine is one of the more activating SSRIs, so nervousness, restlessness and trouble sleeping are common early on. It's usually taken in the morning. Because it builds up slowly in the body, its side effects and its benefits can both take several weeks to settle.
Can Wellbutrin (bupropion) cause anxiety?
Bupropion has a reputation for causing anxiety because it can be stimulating: jitteriness, trouble sleeping and a racing feeling are listed side effects, especially early on. On average, though, a pooled analysis of 10 trials found that anxiety symptoms improved just as much on bupropion as on SSRIs in people with depression. In depression with high levels of anxiety, SSRIs had a modest edge in response rates (about 6 percentage points). Some people do feel noticeably more anxious on bupropion, and for them that matters more than the average. If anxiety on it hasn't eased after the first few weeks, raise it. In the UK, bupropion is licensed only to help people stop smoking, so it is rarely prescribed for depression.
Can Effexor (venlafaxine) or Cymbalta (duloxetine) make anxiety worse?
These SNRIs act on noradrenaline as well as serotonin. Early on, that can show up as sweating, a faster heartbeat or a wired feeling that can feel a lot like anxiety. Venlafaxine can also raise blood pressure at higher doses.
Can a dose increase make anxiety worse?
A dose increase can bring back some of the start-up effects, including anxiety, even if the first weeks went smoothly. This usually settles again within a week or two. US prescribing information also asks for close monitoring "at times of dosage changes," because mood and behavior can shift around these points. If the anxiety after an increase is severe, or you have any thoughts of self-harm, don't wait for your next review: contact your clinician.
Why can anxiety come back a few weeks into treatment?
Some people feel better in weeks two to four and then hit a rough patch, with anxiety, crying spells or panic returning for a while. It can feel like the medication has stopped working. It can be part of the uneven early course of treatment, but it can also mean the dose or medicine needs reviewing. We explain how the early weeks can go in how long antidepressants take to work . If anxiety keeps building, or you're worried about it, contact your prescriber rather than waiting for your review. If you have any thoughts of harming yourself, seek help straight away.
Can a missed dose or tapering cause anxiety?
Anxiety that starts within a few days of a missed, late or reduced dose is often a withdrawal effect rather than your original anxiety coming back. It tends to come with other signs, such as dizziness, irritability, nausea or brief electric-shock sensations ("brain zaps"). It's most noticeable with medicines that leave the body quickly , such as paroxetine and venlafaxine. It's much less likely with fluoxetine, which leaves the body very slowly.
Two practical points follow. Taking your dose at roughly the same time each day helps. And if you're reducing your dose, anxiety soon after a step down is a reason to talk to your prescriber about slowing the taper, not a sign that you can't come off. Our guide to tapering off antidepressants explains how to tell withdrawal from relapse.
A dose calendar makes a missed day easy to spot when anxiety rises a few days later. Akathisia vs anxiety: how to tell them apart
Akathisia is a less common side effect that is easy to mistake for anxiety. It feels like an intense inner restlessness: an urge to keep moving, pacing, shifting in your seat, being unable to sit or stand still. People often describe it as feeling like they want to crawl out of their skin. It most often starts soon after beginning a medication or increasing the dose.
It matters because it can be very distressing. Severe restlessness and agitation are among the symptoms regulators ask people to report straight away , because in a small number of people they can come before worsening mood or thoughts of self-harm, although a direct cause has not been proven. It does not usually improve by pushing through, and increasing the dose can make it worse. If this sounds like what you are feeling, contact your prescriber promptly, and seek urgent help if you also have thoughts of harming yourself. They can often help by lowering the dose, changing the medicine, or adding a short-term treatment for the restlessness.
When does anxiety on antidepressants need urgent help?
Most anxiety on antidepressants is unpleasant but not dangerous, and it usually settles with time or a change in dose. A few combinations of symptoms are different, because they can point to a crisis, mania or serotonin syndrome. Seek urgent help if anxiety comes with any of the following:
Thoughts of harming yourself or ending your life, or feeling unable to keep yourself safe Feeling unusually high, energetic or reckless, needing very little sleep, or racing thoughts. These can be signs of mania or a mixed state, which some antidepressants can trigger, particularly in people with bipolar disorder that hasn't been diagnosed yet. Fever, heavy sweating, shivering, a racing heart, muscle twitching or stiffness, together with agitation or confusion (possible serotonin syndrome, especially after starting or adding another medicine or remedy that affects serotonin, such as another antidepressant, tramadol, triptans for migraine, or St John's wort) In the US: If there is immediate danger, call 911 or go to the nearest emergency department. The 988 Suicide and Crisis Lifeline is available free at any time by call, text or chat.
In the UK: If you or someone else is in immediate danger, call 999 or go to A&E. For urgent mental health support, use NHS 111 online or call 111. Samaritans are available free on 116 123 at any time.
Elsewhere: find a crisis line near you .
Young adults need closer watching in the first weeks. In the US, antidepressants carry an FDA boxed warning about suicidal thoughts and behavior in people aged 24 and younger. In the UK, NICE advises a review a week after starting for people aged 18 to 25 with depression, and for anxiety disorders weekly checks for the first month for people under 30.
How can you manage anxiety when starting antidepressants?
Start-up anxiety usually passes, but you don't have to just grit your teeth through it. Most of what helps is a small change your prescriber can make, such as the dose or when you take it, plus a few things you can do yourself. Options to discuss with your prescriber include:
Going lower and slower. Dropping back to a lower dose and increasing more gradually is a common and sensible way to reduce early anxiety. Changing the timing. If a morning dose leaves you wired, or an evening dose keeps you awake, the time can sometimes be moved. Check with your prescriber or pharmacist first. Cutting back on caffeine and alcohol. Both can amplify anxiety and disrupt sleep while your body adjusts. Short-term help, used carefully. Occasionally a prescriber may suggest a short course of another medicine for sleep or severe anxiety in the first weeks. Some of these can cause dependence, so they're only used briefly, if at all. Non-drug tools. Slow breathing, a short walk, or the techniques you may already use in therapy can take the edge off a spike. A different medicine, if the anxiety doesn't settle or is hard to tolerate. What usually doesn't help is stopping suddenly. That can add withdrawal symptoms on top of the anxiety and makes it harder to tell what's going on.
Download on the App Store The withClaro app helps you track mood, sleep, energy and side effects between visits, so you walk into your next appointment with a clear picture, not a blank mind.
What to track when anxiety rises on antidepressants
Timing patterns only help if you can see them. A minute a day is enough:
Your anxiety level, 0 to 10, once or twice a day The time you took your dose, and any missed or late doses Any dose change, and the date it happened Physical signs: racing heart, sweating, restlessness, trouble sitting still Sleep, caffeine and alcohol The withClaro app's weekly summary shows which symptoms showed up on low-mood days. In your review, say what changed and when: "Anxiety went from 4 to 7 in the first week, eased to 5 by week three, and jumped again two days after we increased to 100 mg." That gives your prescriber far more to work with than "I've been more anxious."
Frequently asked questions How long does increased anxiety last after starting an SSRI? For most people, start-up anxiety is strongest in the first one to two weeks and then eases. For some it lasts longer, and it can briefly return after a dose increase. If it's still significant after two to four weeks, or is hard to manage at any point, talk to your prescriber.
Can Zoloft make anxiety worse? Yes, temporarily. A short-term rise in anxiety is a common early effect of sertraline. It usually settles within the first few weeks, and a lower starting dose is thought to reduce it.
Can Lexapro cause panic attacks at first? It can, in some people, during the first week or two. This usually settles as the body adjusts. Tell your prescriber, especially if panic attacks are new for you or frequent.
Does Wellbutrin cause anxiety? It can cause jitteriness, restlessness and trouble sleeping, especially early on. On average, studies haven't found that it worsens anxiety more than SSRIs in people with depression, but individual experiences vary. Raise it if it doesn't ease.
Is it anxiety or akathisia? Anxiety is mostly a feeling of worry or dread. Akathisia is mostly physical: an intense urge to move and an inability to sit still, usually soon after starting or increasing a dose. If you feel driven to keep moving, contact your prescriber promptly.
Should I stop my antidepressant if my anxiety gets worse? Talk to your prescriber before stopping. Stopping suddenly can cause withdrawal symptoms, and there are usually other options, such as a lower dose or a slower increase. Seek urgent help if you have thoughts of self-harm or other warning signs.
From the medical reviewer When someone starts an antidepressant for anxiety and feels worse in the first week, I tell them two things straight away. First, this is common, and it does not mean the medicine is wrong for you. Second, it usually settles. The medication changes serotonin signalling quickly, but the brain takes a few weeks to adjust, and in that gap some people feel more of the very thing they came in with. It is frustrating, and I do not pretend otherwise.
Deciding what to do next comes down to how bad it is and which way it is heading. If it is unpleasant but manageable and already starting to ease, we usually hold steady and check in again within a week or two. If it is stopping someone from working, sleeping or getting through the day, I would normally drop back to a lower dose and go up more slowly, rather than stop. I think about switching if things have not settled after a few weeks at a dose they can tolerate, or if the side effects clearly outweigh any benefit.
The one thing I never ask people to wait out is a physical restlessness where they cannot sit still. That needs a prompt call to your prescriber.
Whatever you are feeling, tell your prescriber early. It gives you both more options.
Related articles
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