Ketamine-Assisted Therapy: Hope for Treatment-Resistant Mental Health Conditions

Imagine a medication that works in hours.

Not in six weeks. In hours.

A medication to which, in the aggregated real-world evidence, about 45 out of 100 people with treatment-resistant depression respond, with around 30 reaching remission. Response means the symptoms are cut in half. It does not mean the depression is gone. For a group in which two or more antidepressants did nothing, those are still remarkable numbers. In studies, suicidal thoughts were also reduced within hours.

And still many people have never seriously heard of it.

Many people hear the name ketamine and immediately think: party drug. Anesthetic. Risk of dependence. These questions are understandable, and they are important. This is where a misunderstanding often begins.

Between the operating theater and the party basement, there is a third space. A medical, therapeutic space. A space in which ketamine does not numb, but can open something. And exactly there lies the difference between a crash and a therapeutic process.

1. What ketamine is, and what it is not

Ketamine was developed in the early 1960s as an anesthetic, and it is still used worldwide today. In emergency rooms, in operations, in pain therapy. In anesthesia it has a safety profile that differs from many other anesthetics: breathing is usually preserved, and circulation does not typically collapse. That does not make it free of side effects. Blood pressure and pulse can rise markedly, nausea is common, and with repeated use the liver and the bladder can be affected. This is why I examine beforehand and monitor throughout.

Then something fascinating was discovered. At a much lower dose, sub-anesthetic, it is called, ketamine can produce an almost opposite effect in depression, trauma, and chronic tension. Not numbing. But opening.

And exactly this discovery has turned the psychiatric research of the past twenty years on its head.

2. What happens in the brain, the neurobiology in plain language

Classical antidepressants work on the serotonin or norepinephrine system. That is important and effective. But it takes weeks, sometimes months. And it does not help everyone.

Ketamine takes a different route.

The NMDA receptor: the gateway to change

Ketamine blocks a specific receptor type in the brain: the NMDA receptor, a glutamate receptor. Glutamate is the most important excitatory messenger of the brain. Imagine NMDA receptors like locks that regulate the flow of information between nerve cells. In chronic depression, these locks could be stuck in an unhealthy pattern.

When ketamine blocks these receptors, according to the prevailing model something surprising happens at first: certain nerve cells are briefly freed from an inhibition. That can lead to a short-term rise in glutamate in other regions. This rise in glutamate could trigger a cascade that reaches into the architecture of the cell.

BDNF, mTOR, and synaptogenesis: what may be happening at the cellular level

Imagine BDNF, brain-derived neurotrophic factor, as the fertilizer of the brain. Chronic stress and depression reduce BDNF, the connections between nerve cells become weaker, thinner, fewer.

In animal models, ketamine rapidly triggers an increase in BDNF synthesis, presumably via the mTOR signaling pathway, a kind of cellular hub for growth signals. New synaptic connections form there as a result. In humans this cannot currently be measured directly. What we see is the clinical effect. The mechanism behind it is plausible, but not yet proven. Krystal and colleagues attribute this process, which neuroscientists call synaptogenesis, to both the rapid and the longer-lasting effects of ketamine in 2024 in Neuropsychopharmacology.

What does this mean for a person? In depression, the brain metaphorically receives fewer growth signals. Connections that stand for joy, hope, motivation may become weaker. Ketamine can set a counter-impulse in motion within hours. That distinguishes it from the classical antidepressants, which need weeks.

3. How fast does ketamine work, and how long does it last?

This is perhaps the most fascinating part.

Classical antidepressants need six to eight weeks. Ketamine can begin to act within hours. In studies, the peak of the antidepressant effect lies between 24 and 72 hours after an infusion.

This is not mysticism. The explanation under discussion is synaptic growth processes that could begin immediately after the infusion.

Single infusion versus a series

A single infusion may keep working for up to seven days in many people. That is meaningful, but usually not enough for lasting change. Repeated infusions over two to three weeks can extend the effect, although the optimal number and frequency are still subjects of research.

4. Treatment-resistant depression: when nothing else helps

I bet you know this feeling. Or you know someone who does.

Not sick enough to need a hospital, but not healthy enough to truly live. A life in gray. Medications that do nothing. Sessions that go in circles. That exhausted “I have already tried everything.”

Treatment-resistant depression is defined as the lack of improvement despite at least two adequate antidepressant treatments in the current depressive episode. This affects an estimated one in three people with severe depression.

What does that mean in practice? In treatment-resistant depression, ketamine can bring a noticeable relief within hours. It is not a magic remedy. Ketamine is currently one of the fastest-acting options we have in treatment-resistant depression. Other established procedures such as electroconvulsive therapy are comparably effective in head-to-head studies. What distinguishes ketamine is above all the speed, not automatically superiority.

And what about suicidality?

This is a particularly important point. Antidepressants usually need several weeks to reach their full effect. That is hard to endure, but it does not change the fact that they are effective and important. Please never stop an ongoing medication on your own, and not because of this article either. Discuss every change with the doctor who prescribed it.

In studies, ketamine was able to reduce suicidal thoughts within hours, sometimes after a single infusion. That can be clinically very significant. It does not replace emergency care.

5. Bipolar depression: when the dark phases will not lift

People with bipolar disorder know a particular dilemma: many medications help against mania, but barely against the deep depressive phases. And exactly in those phases lies the greatest risk.

6. PTSD: when the trauma keeps living in the nervous system

Post-traumatic stress disorder arises after extreme experiences. Violence, loss, accidents, emotional neglect. The symptoms are wearing: flashbacks, nightmares, dissociation, constant over-arousal, the sense of being cut off from oneself or from the world.

What may make ketamine particularly relevant here? Traumatic memories are deeply encoded in the nervous system. Classical therapies need time to reach those layers. Ketamine can ease access to emotionally charged content by briefly reducing cognitive control and opening access to inner experience.

7. Ketamine can open a door, therapy can turn it into a room

To me, this is one of the most important points. And it is often underestimated.

Ketamine changes consciousness. It opens a window in which new perspectives can arise, in which old patterns are less rigid, in which something stuck becomes movable again. But this window closes.

What you do in that window makes the difference. That is the core of ketamine-assisted psychotherapy.

Ketamine alone is like a door that opens briefly. Without integration, it is easy to walk past it. With accompaniment, it can become a room you can actually step into.

8. What you experience in a session

Every experience is unique. But there are recurring patterns that most people describe.

Many people experience this as both shaking and clarifying. Sometimes something rises that has had no place for years. That can be overwhelming. But this is exactly what a safe therapeutic frame is for: not to push it away, but to say: you are allowed to be here.

9. Does ketamine cause addiction? An honest answer

I hear this question in every first conversation. And it is justified.

Ketamine is misused recreationally, often in very high doses, daily, combined with other substances. That carries real risks: psychological dependence, bladder damage (so-called ketamine cystitis), and memory problems with chronic use.

But that is a completely different setting from therapeutic use.

In therapeutic use, different parameters apply: precisely dosed single doses with long intervals between them, under medical supervision, with psychological preparation and integration. A physical withdrawal syndrome as with alcohol, benzodiazepines, or opioids is not described for ketamine in the same way. It carries a potential for misuse nonetheless. That is why every application belongs in medical hands.

But: psychological dependence can develop when people use ketamine to escape feelings, without therapeutic accompaniment. The opposite of the therapeutic goal. That is why the frame is decisive. The point is not to create a new attachment. The point is to become freer.

10. Mechanism and clinical practice: what the neurobiology means for the experience

I would like to go one step further. Because the neurobiology can explain something that many patients describe intuitively, but find hard to put into words.

In severe depression and chronic stress there are indications of a reduced density of synaptic connections, above all in the prefrontal cortex, which is responsible for perspective, planning, and emotional regulation. These findings come predominantly from animal models and examinations of brain tissue. In the living human being we cannot currently see this directly.

What ketamine could set in motion is, at its core, a regenerative process. In animal models, new synaptic connections form within hours. This state of heightened neuronal plasticity could be the biological window in which therapeutic work can act more deeply. In humans this is not proven.

Many people describe after a session that their head had become quieter and that they could feel something again.

How much of this goes back to the neurobiological effect and how much to expectation, attention, and setting cannot honestly be separated. Probably both act together. That does not make the experience any less valuable.

11. How a treatment with me unfolds

Every person brings their own story, a different nervous system, and an individual body. That is why no treatment with me starts with an infusion. It starts with real listening.

Step 1: history and integrative diagnostics

We begin with an in-depth conversation about your life, your symptoms, previous therapies, and inner themes. This also includes physical diagnostics, because emotional state and biochemical foundations can be closely connected.

Step 2: preparation and setting conversation

Before you receive ketamine, we clarify: what is your goal? What is allowed to come up? What do you need if it gets intense? This conversation is decisive. It gives your experience a safe frame.

Step 3: the infusion, precisely dosed, medically monitored

The dose is calculated by body weight and lies far below an anesthetic dose. I set the exact dose individually. The infusion runs slowly over about forty minutes, with continuous monitoring of heart rate and blood pressure. Eye protection reduces external stimuli. Music carries the process emotionally. I am present the entire time.

The setting makes the difference. Ketamine can do more when the room around it is shaped properly.

Step 4: integration

After every session we talk: what did you experience? Which feelings were there? What has shifted? The experience is the impulse. Integration turns it into change.

Step 5: course and closure

How many sessions make sense is something we decide together as we go. Some people describe more clarity afterwards, more access to feelings, more self-leadership. Those are individual courses from my practice, not a success rate. My goal is not for you to stay with me. My goal is that you learn to accompany yourself.

12. Why I always work integratively

Many people, when they think of mental health, think only of conversations, diagnoses, and medications. But what about a vitamin D deficiency that can impair drive and mood? About chronic inflammation that weighs on body and nervous system? About a dysbiosis in the gut that could influence emotional experience via the gut-brain axis?

Your emotional state can have biochemical foundations. Ketamine does not treat isolated symptoms. It is part of an integrative approach that takes all levels into account.

13. Who ketamine is suited for, and who it is not

What if there is no severe diagnosis?

If you have read this far, you have learned a lot about treatment-resistant depression, PTSD, and bipolar disorder. That is the scientific language in which ketamine is researched and described. Studies so far exist only for people with a diagnosis.

In my practice I also see people without a severe diagnosis who cannot move forward through thinking alone. Whether a ketamine-assisted treatment is justifiable in an individual case is decided only after a medical examination and only where there is a clear medical indication. Without an indication I do not prescribe ketamine.

We live in a culture that places cognitive understanding above bodily experience. We analyze, name, categorize. We know a lot about ourselves. And still little often changes. Not because we know too little, but because knowing alone is often not enough. For some people the key may lie more in experiencing than in understanding.

Ketamine can temporarily make the analytical part of the mind, the part that constantly judges, controls, and comments, quieter. What remains is a deeper access to what is actually going on inside us. Images, feelings, connections that do not appear in normal waking consciousness. That is not a mystical process. The mechanism under discussion is a neurobiological one: fewer filters, more access.

So please do not let the clinical language in this article put you off. If you have the feeling that pure thinking is reaching its limits, a conversation is the right first step. Whether that leads to a ketamine-assisted treatment is not decided by it. That depends on the examination, the diagnosis, and a careful assessment, and in many cases a different path is the better one.

14. Self-check: could ketamine be relevant for you?

Ketamine within the system, the connection to my other specialty areas

Mental health is rarely isolated. Associations are discussed between mood and physical factors such as inflammation, the gut microbiome, mold toxins, or a heavy-metal load. Reliable studies combining these topics with a ketamine treatment do not exist so far. I look at these levels because they can play a role in an individual case, not because an association has been proven.