Why Ketamine-Assisted Therapy Usually Involves 4–8 Sessions

What the research says about why a single ketamine session isn’t a full treatment

When people first learn about ketamine-assisted therapy (KaT), one of the most common questions is:

“Why does it take multiple sessions?”

You may have heard stories of someone having a powerful psychedelic experience in a single session and wonder if the same should apply to ketamine. Others worry that clinics recommending 6–8 sessions may simply be trying to increase revenue ($).

The reality is much simpler: most research on ketamine for depression and other mental health conditions uses a series of treatments; not a single session.

At Access Therapy, when we recommend 4–8 ketamine-assisted therapy sessions (often around six), it’s because that structure is the most consistent with what research and clinical experience suggest leads to better and longer-lasting outcomes.

Here’s why.

1. Ketamine works quickly — but a single dose often fades

One of the most exciting things about ketamine-assisted therapy is how quickly it can help relieve symptoms of depression and distress. Research shows that the medicine can reduce depressive symptoms within hours, which is very different from traditional antidepressants that often take weeks to work.

But early studies also revealed something important: the benefits of a single ketamine-assisted therapy session are often short-lived.

In many patients, the antidepressant effects begin to fade within about 5–8 days after one session.

Because of this, researchers began studying repeated ketamine-assisted therapy treatments, which have consistently shown stronger and more durable improvements than a single dose.

In other words, one session can sometimes provide relief — but multiple sessions help stabilize and extend the benefits.

2. Most clinical research uses about six treatments

If you look at how ketamine-assisted therapy is studied in clinical trials, you’ll notice a clear pattern: treatment is usually delivered as a short series.

For example:

• Many treatment-resistant depression studies use six medicine sessions over 2–3 weeks as an initial treatment protocol.

• Research comparing single vs. repeated medicine doses found that repeated treatments produced stronger antidepressant effects than a single treatment alone.

• Other clinical research also administers six sessions and tracks symptom improvements over time, with many patients responding after several treatments rather than the first one.

This is why many modern ketamine-assisted therapy programs — including psychotherapy-based models — recommend a series of sessions rather than a one-time experience.

Healing rarely happens in a single moment. More often, it unfolds over a process.

3. The therapy part of ketamine-assisted therapy matters

Ketamine doesn’t just temporarily change mood, it appears to affect neuroplasticity, meaning the brain becomes more capable of forming new neural connections.

This temporary window of flexibility may make the brain more receptive to psychological change and learning.

That’s one reason why the medicine is increasingly paired with psychotherapy. When therapy is integrated into the process, it can help people:

• process emotional experiences

• gain new insights

• shift long-standing patterns

• translate those insights into real life change

Research examining ketamine combined with psychotherapy suggests this approach may help sustain the antidepressant benefits of ketamine treatment.

But meaningful psychological change usually takes more than one session.

It often requires preparation, multiple medicine sessions, and integration work over time.

4. Most people’s experience unfolds across several sessions

While some clients do have meaningful insights in their first session, the deeper therapeutic work usually unfolds gradually.

Clinically, many people report a progression like this:

Sessions 1–2
Getting familiar with the medicine, building trust in the process.

Sessions 3–4
Deeper emotional processing, perspective shifts, or new insights.

Sessions 5–6+
Integration — applying insights into relationships, habits, and daily life.

Interestingly, some studies have found that many patients don’t show significant clinical response until after several treatments, highlighting the importance of completing a full treatment series.

5. A full treatment series can lead to stronger outcomes

Emerging research suggests that repeated ketamine-assisted therapy sessions tend to produce more robust improvements than minimal exposure.

For example, studies examining serial medicine treatments have found response rates above 60% in people with treatment-resistant depression after completing a full treatment protocol.

Repeated sessions may allow the brain to:

• reinforce new neural pathways

• consolidate emotional breakthroughs

• integrate new perspectives into everyday life

Instead of being a single “aha moment,” healing becomes a gradual restructuring of patterns.

The bottom line: why we recommend 4–8 sessions

Ketamine-assisted therapy can open the door to change very quickly.

But meaningful healing usually happens when that opening is supported, repeated, and integrated over time.

That’s why most research-informed treatment models involve a series of sessions — typically between 4 and 8.

At Access Therapy, our recommendations are guided by one principle:

We want clients to have the best possible chance of lasting improvement.

Not just a powerful experience but real, sustained change in how you feel and live your life.

If You’re Curious or Considering Ketamine-Assisted Therapy(KaT) or Psychedelic-Assisted Therapy (PaT) in General

It’s normal to feel both curious and cautious about psychedelic‑assisted therapy. Questions about safety, legality, readiness, and fit are not only welcome — they’re important.

If you’re exploring whether PaT might be right for you, we encourage a slow, informed approach. Learning, asking questions, and understanding your own mental health history are meaningful first steps.

As this work becomes available in Hamilton, our commitment is to offer care that is ethical, grounded, and deeply respectful of the vulnerability involved in healing.

Curious and Want to Learn More?

If you’re wondering whether psychedelic-assisted therapy might be right for you — or you simply want more information — we offer a free, no-obligation information call.

This call is a space to:

• Ask questions in a grounded, non-pressured way

• Learn more about our upcoming ketamine-assisted therapy program

• Understand what the process involves and whether it may be a fit for you

There is no expectation to commit. Our goal is to support informed, thoughtful decision-making.

Future blog posts will explore how psychedelic-assisted therapy works, who it may (and may not) be appropriate for, preparation and integration practices, and what current research tells us about long-term outcomes.