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

Imagine there was a medication that worked in hours.

Not in six weeks. In hours.

A medication that, in clinical studies of people with treatment-resistant depression, achieves response rates of up to 50 %, even when two or more antidepressants have already failed. A medication that can reduce suicidal thoughts within hours, before any conventional therapy has even begun to take effect.

And yet many people have never seriously heard of it.

Many people hear the name ketamine and immediately think: party drug. Anaesthetic. Addiction risk. These questions are understandable. And they matter. Because this is exactly where the real misunderstanding begins.

Between the operating room and the party basement there is a third space. A medical, therapeutic space. A space in which ketamine does not anaesthetise but can open something. And that is precisely the difference between a crash and healing.

1. What ketamine is, and what it is not

Ketamine was developed as an anaesthetic in the early 1960s and is still used worldwide today. In emergency departments, in surgery, in pain medicine. It is one of the few substances that does not depress respiration, stabilises circulation, can be dosed extremely reliably, and has hardly any toxic side effects when used correctly.

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

And it is precisely this discovery that has turned psychiatric research on its head over the last twenty years.

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

Classical antidepressants work on the serotonin or noradrenaline 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 particular type of receptor in the brain: the NMDA receptor, a glutamate receptor. Glutamate is the brain's most important excitatory neurotransmitter. Imagine NMDA receptors as gates that regulate the flow of information between nerve cells. In chronic depression these gates may be permanently stuck in an unhealthy pattern.

When ketamine blocks these receptors, something surprising happens at first: nerve cells are briefly released from a particular form of inhibition. This leads to a short-term rise in glutamate in other regions. And this glutamate surge activates a cascade that intervenes directly in the cell's architecture.

BDNF, mTOR and synaptogenesis: the actual healing process

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

Ketamine very rapidly triggers an increase in BDNF synthesis. This happens via activation of the mTOR signalling pathway, a kind of cellular hub for growth signals. The result: new synaptic connections form, damaged ones are repaired. This process, which neuroscientists call synaptogenesis, was described by Krystal and colleagues in 2024 in Neuropsychopharmacology, and is responsible for both the rapid and the longer-lasting effects of ketamine.

What does this mean for the person? Metaphorically speaking, in depression the brain receives fewer growth signals. Connections that stand for joy, hope, motivation become weaker. Ketamine can set this process in motion within hours, and biologically that is unique among the known antidepressants.

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

This is perhaps the most fascinating part.

Classical antidepressants need six to eight weeks. Ketamine begins to work within hours. The peak of the antidepressant effect is reached 24 to 72 hours after an infusion.

This is not mysticism. These are the synaptic growth processes that begin immediately after the infusion.

Single infusion vs. course of treatment

A single infusion (0.5 mg/kg over 40 minutes) lasts up to seven days in many people. That is meaningful, but not enough for sustained change. Repeated infusions over two to three weeks can prolong the effect, although the optimal number and frequency are still under research.

4. Treatment-resistant depression: when nothing else works

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

Not sick enough to need hospital. But not well enough to really live. A life in grey. Medications that do nothing. Conversations that go in circles. That exhausted "I have already tried everything."

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

What does this mean in practice? In treatment-resistant depression, ketamine can bring noticeable relief within hours. It is not a magic bullet. But in the research it is by far the fastest and most powerful instrument we have for people for whom everything else has failed.

And what about suicidality?

This is a particularly important point. Classical antidepressants take weeks to develop their anti-suicidal effects, and during the first two weeks the suicide risk can briefly even increase. Ketamine can reduce suicidal thoughts within hours, sometimes after just a single infusion. Clinically, this can be life-saving.

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 it is precisely in those phases that the greatest risk lies.

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

Post-traumatic stress disorder develops after extreme experiences. Violence, loss, accidents, emotional neglect. The symptoms are wearing: flashbacks, nightmares, dissociation, constant hyperarousal, the feeling of being cut off from yourself or 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 alone opens a door, therapy turns it into a room

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

Ketamine alters consciousness. There is a window in which new perspectives can emerge, in which old patterns are less rigid, in which something that has been locked away can become movable again. But that window closes.

What you do inside that window is what makes the difference. That is the heart of ketamine-assisted psychotherapy.

Ketamine alone is like a door that opens briefly. Without integration, you walk past it. With guidance it becomes a room you can actually enter.

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 shaking and clarifying. Sometimes something rises up that has had no place for years. That can be overwhelming. But this is exactly the point of a safe therapeutic frame: not to suppress. But to say: you are allowed to be here.

9. Is ketamine addictive? An honest answer

I hear this question in every initial consultation. And it is a fair one.

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), memory impairment with chronic use.

But that is a completely different setting from therapeutic use.

In therapeutic use, fundamentally different parameters apply: precisely dosed individual administrations with long intervals between them, under medical supervision, with psychological preparation and integration. Ketamine does not produce a physical withdrawal syndrome the way alcohol, benzodiazepines, or opioids do.

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

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

I want to go one step further. Because the neurobiology explains something that many patients describe intuitively but find hard to put into words.

In severe depression or chronic trauma, synaptic connections literally shrink. Not metaphorically. Microscopically measurable. The prefrontal cortex, which is responsible for perspective, planning, and emotional regulation, loses connection density.

What ketamine sets in motion is, at its core, a process of regeneration. New synaptic connections form within hours. This state of heightened neuronal plasticity, which lasts for a certain period after the infusion, is the biological window in which therapeutic work can reach more deeply.

Many patients describe it like this: "My head was finally still. And for the first time in years I could feel what was really there."

That is not suggestion. That is synaptogenesis.

11. How a treatment with me unfolds

Every person brings a unique 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-taking and holistic diagnostics

We begin with an in-depth conversation about your life, your symptoms, previous therapies, and inner themes. That also includes physical diagnostics, because emotional state and biochemical foundation are inseparable.

Step 2: Preparation and setting conversation

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

Step 3: The infusion, precisely dosed, medically monitored

0.5 mg/kg of ketamine slowly intravenously over about 40 minutes. Heart rate and blood pressure are continuously monitored. An eye mask reduces external stimuli. Music supports the emotional process. I am present the entire time.

The setting makes the difference. Ketamine can do more when the space is set up correctly for it.

Step 4: Integration

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

Step 5: Course and conclusion

After several sessions (depending on the situation, typically 4–6) a new inner space often emerges: more clarity, more access to feelings, more self-direction. My goal is not for you to stay with me. My goal is for you to learn how to accompany yourself.

12. Why I always work holistically

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

Your emotional state has biochemical foundations. Ketamine does not treat isolated symptoms. It is part of a holistic approach that takes every level into account.

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

Ketamine is not only for severe diagnoses.

If you have read this far, you have learned a lot about treatment-resistant depression, PTSD, and bipolar conditions. That is the scientific language in which ketamine is researched and described. But I want to be honest: that is not the full picture of what I see in my practice.

Many of the people who come to me have none of these severe diagnoses. No treatment-resistance, no clinical condition listed in a DSM catalogue. And yet they have benefited deeply from ketamine.

We live in a culture that places cognitive understanding above bodily experience. We analyse, name, categorise. We know a lot about ourselves. And yet often little changes. Not because we know too little, but because knowledge alone is not enough. The key lies in the experiencing, not in the understanding.

Ketamine can temporarily quiet the analytical part of the mind, the part that is constantly evaluating, controlling, and commenting. What remains is a deeper access to what is really going on inside us. Images, feelings, connections that do not appear in ordinary states of consciousness. This is not a mystical process. It is neurobiology: less filter, more access.

So please don't let the clinical language of this article put you off. If you feel that you are reaching the limits of pure thinking, that you want to feel more and analyse less, or that you are looking for a deep experience that can spark real change from within, that is a fully valid reason for a conversation. You don't have to be sick to benefit from ketamine. You only have to be willing.

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

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

Mental health is rarely an isolated matter. In my practice I regularly see: people struggling with treatment-resistant depression or PTSD often carry a biological burden at the same time, mold toxins that produce neuroinflammation, heavy metals that disrupt neurotransmitter synthesis, or a dysbiotic gut microbiome that destabilises mood through the gut-brain axis. Ketamine opens a window. But that window is most useful when the entire system is working with it.