How Fast Does Ketamine Work for Anxiety?

Ketamine can produce rapid antidepressant and anxiolytic effects in a large percentage of people who take it, but not everyone stands to benefit from the experience. Here’s how long it may take for ketamine to be effective.

By J Gordon Curtis Last Updated: February 12, 2024
Last Updated: February 12, 2024

Ketamine ads and clinics make it seem like a miracle drug capable of curing even the most stubborn of mental health concerns. While it does show a considerable effect on a large number of disorders for many, most research is inconclusive and often conflicting.

Positive results rarely last longer than a week or two — requiring patients to take ongoing treatment to maintain relief.

Studies show that a few specific anxiety disorders are better disposed to ketamine therapy, but even this is uncertain.

Let’s take a look at the issue from all angles to determine if ketamine treatment is the right choice for your anxiety. 

Here, we discuss the following forms of anxiety and the speed at which ketamine may offer relief:

Quick Answer: How Fast Does Ketamine Work?

There’s really no one-size-fits-all-all for ketamine. Many patients report improvements in symptoms almost immediately following treatment; others don’t find relief until the second or third session. Some don’t find relief whatsoever.

Ketamine typically doesn’t work as well for anxiety as drugs like benzodiazepines for alleviating symptoms of anxiety, but it may offer a more long-term source of relief when paired with professional psychotherapy. 

Specifically, therapeutic approaches designed to uproot the underlying, unconscious causes of anxiety have shown the best efficacy for treating anxiety. These treatments often require several weeks of consistent therapy before they’re effective.

Modalities such as IFS (internal family systems), shadow work, and CBT (cognitive behavioral therapy) pair very well with ketamine and other psychedelics.

What Does the Research Say About Ketamine & Anxiety?

Research surrounding the use of ketamine therapy to treat anxiety is mixed at best. A rodent study from 2020 found the anxiolytic (anti-anxiety) effect of ketamine was only apparent immediately after dosing and quickly wore off [1].

These researchers also performed a comprehensive review of the pre-clinical research on ketamine for anxiety treatment and concluded:

There appears to be no pattern in the outcome of the experiments that evaluated the effects of ketamine on anxiety/fear-related behaviors.

This doesn’t mean ketamine can’t help with anxiety, however. Anxiety, like depression, has a multitude of layers and varieties — each person is unique, and so are their mental health needs. 

Differences in gender, metabolic makeup, environment, diet, genetic or hormonal signals, and more can impact the appropriate course of care for anxiety. For this reason, the first step to considering ketamine treatment for anxiety is always to discuss it with a qualified mental health professional (preferably one who isn’t financially incentivized to recommend ketamine).

One thing we do know is that ketamine is not a permanent solution for anxiety. One review from 2022 concluded prior research indicates the anxiolytic effect of ketamine could “persist for up to one week” after ketamine sessions [2].

Ketamine utilizes novel mechanisms for addressing anxiety, which could shake up the entire future of treatment. 

We have yet to answer the question of whether ketamine itself is this tool or if it’s pointing us towards a better solution, however. While the initial studies are shaky, its unique pharmacology has sparked interest in developing related compounds in an effort to find one that works better.

How Ketamine Works for Anxiety

Ketamine primarily impacts N-methyl-D-aspartate receptors (NMDAR), the same location responsible for the antidepressant effects of ketamine

NMDAR helps regulate the flow of signals throughout the body — which may be an integral, overlooked mechanism for treating a long list of mental health conditions. This could explain why ketamine has been found so effective for a diverse range of mental health conditions in recent years.

Here’s a quick breakdown of the chain reaction ketamine and its effects on the NMDA receptors sets off [2, 3]:

ActionRole of AreaPotential Outcome
Inhibition of gamma-aminobutyric acid (GABA)An inhibitory neuronal messenger responsible for dulling (and thus helping control) certain messages and activities in the brainGlutamate can freely fire off in higher concentrations without the inhibition of GABA
Increases in glutamateExcites neurons and encourages activityImproves activity within the brain and activates AMPAR
Activation of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPAR) Promotes “synaptic plasticity” — or the ability to modify connections in the brainIn addition to the therapeutic potential of synaptic plasticity on its own, this also leads to a series of events resulting in the release of norepinephrine and serotonin
Release of norepinephrine and serotoninBroadly speaking, these are responsible for energy and happiness levels (respectively), though they have far more complicated rolesThe boost of energy and happiness may be a crucial component of the antidepressant/anxiolytic action of ketamine and is often a target for other medications
Mu-opioid receptor activityKetamine has activity at all three opioid receptors, but the mu-opioid receptor has a delicate connection with NMDAR and is responsible for our pain signaling pathway between brain and bodyIn addition to potentially contributing to the dissociative effects of ketamine, this can also lead to a release of endorphins and dopamine
Elevations in dopamine and endorphinsHelp control happiness and manage stress, respectivelyMay go a long way in improving the mood and mental outlook of patients in ketamine therapy

Other Ways Ketamine Might Help With Anxiety

While NMDAR is the main area of study when it comes to ketamine, there are a variety of ways it might help with anxiety from a therapeutic standpoint. These factors depend primarily on the environment in which the ketamine session happens and the amount of support they provide.

These elements of the ketamine experience may contribute to an anxiolytic effect:

1. Dissociation

When you feel anxious in your own skin, sometimes it helps to step outside of your body for a little while. Ketamine is a dissociative anesthetic, meaning high doses can completely divorce a person from their sense of self.

Related — Euphoric Nothingness: The Dichotomy of the Dissociative Healing States

2. Paradigm Shifts

Seeing the world in a new light after a ketamine session can be powerful, especially when you take care to integrate the experience. The vast majority of positive outcomes on psychedelics are the result of a new way of seeing and understanding the world around you, as opposed to simply treating chemical imbalances.

3. Depression Reduction

Anxiety has many forms but commonly shows up in people experiencing depression. While the antidepressant effect of ketamine rarely lasts longer than a couple of weeks, the alleviation of depression can help many struggling with some forms of anxiety. 

As with other forms of psychedelic-assisted psychotherapy, the drug alone is rarely enough for lasting change. Rather, the most help comes from taking the drug in a safe and welcoming environment after careful preparation followed by weeks of discussion and integration of the experience.

You will unlikely find this at any clinic — telehealth or otherwise. Having a personal therapist will typically be the most impactful way you could address your anxiety and seek lasting change.

How Ketamine Can Worsen Anxiety

The effects of ketamine can feel overwhelming and disorienting, leaving patients confused and potentially worsening their anxiety in the long run. For the most part, ketamine doesn’t seem to increase a person’s panic response, but in some cases, users report a feeling of “terrifying nonetheless.” 

Ketamine therapy uses high doses of the drug and can match the experience of large recreational doses. Without the guidance of a trained therapist, this can overwhelm participants.

Research has also shown ketamine use — particularly frequent use — often results in social withdrawal and isolation [4].

It’s common for papers to conclude that ketamine won’t worsen symptoms of anxiety in most participants, but it’s rarely the case for all.

One study from the telehealth giant Mindbloom — which funded the study, paid researchers, and provided all participants and clinicians — declared at-home ketamine “safe and effective [5]. The participants in this study underwent extensive criteria for inclusion (including no prior drug use), and one patient still had to seek in-patient care for worsening anxiety after the fourth session.

It’s crucial to note this because the field of ketamine is overrun with corporate interests, and very few studies exist without extensive conflicting interests. Frequently, an author holds a patent pertaining to ketamine, runs a clinic, or accepts money from pharmaceutical companies (to name a few red flags).

One study, as an example, concludes that large doses of ketamine won’t worsen anxiety in patients with post-traumatic stress disorder [6]. This bold conclusion came from a study on just 55 patients — of which only 15 had PTSD, with the remaining having traumatic experiences but not meeting the criteria. 

Additionally, one of the authors is a partial holder of a patent on using ketamine to treat depression. It stands to reason that a world-shattering experience can negatively impact anyone not fully prepared for it, however.

What Forms of Anxiety Can Ketamine Treat?

There are several forms of anxiety, and some may be more conducive to ketamine therapy than others. 

While it’s important to note that all research into ketamine and other psychedelics is preliminary, some studies have found ketamine could help with the following:

1. Ketamine Treatment for Refractory Anxiety

Several studies have looked into how effective ketamine is at treating persistently untreatable (or refractory) anxiety. Anxiety and depression often have a close relationship with each other, and refractory anxiety may or may not be a component of treatment-resistant depression as well.

In this sense, the treatment of the depressive symptoms often helps relieve anxiety symptoms alongside it. However, it’s important to note that research doesn’t always show reliably high percentages of participants have this effect, and results rarely last over a week or two [2].

What little research there is on the topic often revolves around the antidepressant action of ketamine with a passing interest in anxiety. However, there have been promising results showing ketamine can be a rapidly effective treatment for participants, albeit a short one.

2. Ketamine Treatment for Social Anxiety & General Anxiety Disorder

Social and general anxiety disorders are particularly hard to treat because the condition can vary significantly from person to person. Studies conflict on whether ketamine can be helpful, but some promise has shone through in introductory research.

One study evaluated participants with social anxiety disorder in a crossover study where they would take ketamine or a placebo and then the reverse a month later. They used two different tests to determine anxiety levels, and only one of them indicated a significant improvement from ketamine [7].

The authors do very little to discuss why this discrepancy exists, but it’s worth questioning the efficacy of ketamine based on this fact. Several people find rapid relief from ketamine for their anxiety symptoms and are capable of maintaining them through regular sessions, but, like all medications, it won’t be the answer for everyone.

Add the variability of general and social anxiety disorders, and the complexities compound exponentially.

3. Ketamine Treatment for Obsessive-Compulsive Disorder (OCD)

Obsessive-compulsive disorder is related to anxiety and can be debilitating in the lives of those suffering from it. Ketamine has shown the potential to reduce OCD symptoms, but it is rarely a significant, permanent solution.

One study found none of the 10 participants responded to the effects of ketamine immediately but rarely after the acute experience of ketamine wore off [8]. Another study demonstrated only half of the 8 participants experienced an effect lasting longer than one week [9].

For people suffering from OCD, those 45 minutes of relief wearing off along with the effects of the drug can still be worth it. After returning to baseline, participants may find their trip to “ketamine space” — AKA a “K-hole” — helped simply by removing them from their compulsive behaviors momentarily.

Still, this is one of the lesser-researched potential applications of ketamine, so it’s best to discuss this in-depth with a psychiatrist beforehand.

4. Ketamine Treatment for Post-TraumaticPost-Traumatic Stress Disorder (PTSD)

Perhaps no mental health disorder gets more attention than PTSD when it comes to psychedelic therapy. As a debilitating condition, researchers have desperately sought out the solution for years, and ketamine may be (at least part of) the answer.

As with all other conditions, the efficacy of ketamine treatment limits itself to 1–2 weeks, with many reporting rapid or instant benefit after use [10]. As a serious, complex condition, treating PTSD with a psychedelic intervention carries multiple risks.

It’s possible to re-trigger the traumatic experience through the psychedelic state and potentially worsen the condition altogether. That said, research does show this to be exceedingly rare when it comes to ketamine.

Part of this may be the dissociative effects of the drug compared to other psychedelic substances, along with the dopaminergic release from the opioid receptors. While there’s no guarantee that you’ll be in a happy mood on ketamine, it’s often easier than some other drugs.

Don’t take this to mean it’s safe to enter into it without preparation, though. 

Concerns Surrounding Ketamine Therapy for Anxiety

Unlike other drugs used in psychedelic-assisted psychotherapy, ketamine’s toxicity and potential for dependency and addiction raise other concerns. 

Here are some of the potential problems surrounding ketamine treatment for anxiety:

1. Long-Term Ketamine “Boosters”

Every ketamine treatment option requires ongoing sessions with the drug, often resulting in 2–8 sessions per month — often with high doses. Even clinics that advertise just a few sessions generally coerce patients into buying “boosters” with more treatment sessions.

The problem is that ketamine metabolizes into toxic compounds like norketamine, which end up in the bladder, where they erode the protective lining and can cause serious bladder pain.

This discussion typically only happens for recreational use, but clinical use still carries this possibility.

Even the Mindbloom study, which didn’t allow for participants with prior ketamine use, had a participant who had to seek a urologist after just four doses [5]. This is far from the norm, but it’s worth understanding beforehand if you’re considering ketamine as a therapeutic option.

Additionally, ketamine has a high potential for dependence, tolerance, and addictive/chaotic use. Many of the biggest concerns with ketamine go away with the cessation of ketamine use — addiction makes this harder. 

Trapped in chaotic use, people sometimes continue using ketamine after developing serious health problems.

Concerns surrounding the urinary tract, liver, and abdominals are the most important and carry the potential for hospitalization or worse if ketamine users don’t stop using after symptoms appear. 

2. Ketamine Therapy is Expensive

Ketamine therapy is often expensive, ranging anywhere from $100–2000 per session. Telehealth providers offer cheaper doses with low barriers for entry but rarely include much guidance, preparation, or integration support. 

If you’re considering ketamine for the treatment of a major anxiety disorder, it’s likely best to seek out an off-label ketamine clinic instead. They will have clinicians who can confidently walk you through what to expect, be there to make sure nothing goes wrong, and adjust your treatment schedule as needed.

While telehealth companies do little more than mail ketamine doses to your door, they can still be effective alternatives if you already have a mental health provider you trust.

Everyone is different, and it might be more effective to take ketamine at home with someone you trust and discuss the experience before and after with a licensed provider. 

Just make sure you bring it up with them before you take the ketamine. Depending on where you live and who your provider is, this may or may not be a realistic option for them.

Alternatives to Ketamine Therapy for Anxiety

Medications, psychologists/psychiatrists, somatic therapy, meditation, breathwork, and more may treat conditions across the spectrum of severity.

If it’s left unchecked, anxiety can wreak havoc on a person’s life, and it’s important to take managing it seriously. Whatever solution you reach for should be one you’ve thoroughly researched and discussed with a qualified professional.

Other psychedelic-assisted psychotherapies involving magic mushrooms or MDMA (3,4-Methyl​enedioxy​methamphetamine) may also prove beneficial.

Related: Magic Mushrooms for Anxiety

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