Combining Ketamine-Assisted Psychotherapy and EMDR: What the Research Now Shows

Allison Kalivas

My colleague Dr. Joey Tadie wrote about combining KAP and EMDR back in 2024, when we were largely working from clinical rationale and early observation. A year later, the research has caught up in meaningful ways — and I wanted to add my own perspective: what the evidence now shows, what I’ve seen in my own work with clients, and where the science still has honest gaps. This is that update.

If you’ve been researching ketamine-assisted psychotherapy in Denver, you’ve probably run into a wall of contradictions. Some sources make it sound like a miracle. Others make it sound reckless. And somewhere in between, you’re trying to figure out whether this is something that could actually help you—or whether it’s just another wellness trend with good marketing.

That skepticism makes sense. It’s worth honoring, actually. The decision to try something like ketamine-assisted psychotherapy shouldn’t feel casual—it should feel like a considered choice, made with real information.

So here’s what we can offer: an honest look at what the research currently shows about KAP, how we combine it with EMDR at Catalyst Center, and who it tends to work best for. No hype. No vague promises about “unlocking your healing.” Just what we know, what we’ve seen clinically, and where the science still has gaps.

Let’s start with the basics, because the terminology alone creates confusion. Ketamine-assisted psychotherapy—KAP—is not the same thing as a ketamine infusion at a clinic where you sit in a recliner with an IV and go home afterward. Those infusions can shift mood temporarily, but they don’t involve therapy. The “assisted” part matters.

In KAP, ketamine is administered at a low, carefully calibrated dose within a therapeutic relationship. A trained clinician is present throughout the session. The medicine isn’t the treatment—it’s a tool that opens a window. What happens inside that window, with a therapist who knows your history and your nervous system, is where the real clinical work takes place.

And no—this isn’t “just getting high.” That’s probably the most common question we hear, and it deserves a direct answer. The doses used in KAP are sub-psychedelic. You remain aware, present, and able to engage in the therapeutic process. The experience can feel expansive or unfamiliar, but the goal isn’t altered consciousness for its own sake. The goal is creating the neurobiological conditions for deep processing to happen.

The research on KAP has moved meaningfully since 2021. We’re no longer relying on anecdote and early case studies. Peer-reviewed findings from 2024 and 2025 are giving us a clearer—and more nuanced—picture of what ketamine-assisted psychotherapy can and can’t do. Here’s what the current evidence tells us.

KAP efficacy for depression, PTSD, and anxiety. A 2025 systematic review published in Current Treatment Options in Psychiatry analyzed eight studies involving 421 participants and found significant reductions in depressive symptoms with KAP for treatment-resistant depression. The review concluded that combining ketamine with structured psychotherapy shows real promise—though the authors were careful to note that small sample sizes and protocol variability still limit definitive conclusions.

The findings on PTSD are similarly encouraging. A 2024 systematic review and meta-analysis by Almeida et al., published in Clinical Neuropsychiatry, examined ten studies—including five randomized controlled trials—with a total sample of 363 individuals. The analysis found that ketamine produced statistically significant improvements in PTSD symptoms as measured by the PCL-5, with a standardized effect size of 0.25 at treatment endpoint. Notably, the improvements were not statistically significant at the 24-hour mark alone; they became significant over the full course of treatment. That distinction matters: it suggests the benefit builds with repeated sessions rather than appearing as a single-dose fix.

What makes the Almeida findings particularly relevant for our work is this: four of the ten studies they reviewed combined ketamine with structured psychotherapy—including prolonged exposure and a mindfulness-based modality called TIMBER. The studies that paired ketamine with therapy showed prolonged therapeutic effects compared to ketamine alone. This aligns with what we see clinically: ketamine creates a window, but it’s the therapeutic work inside that window that determines the lasting outcome.

A separate large retrospective study published in 2024 in Psychedelic Medicine reinforced this pattern. Tracking outcomes across 346 KAP patients at three months and 94 at six months, the study found that when ketamine was paired with structured psychotherapy and integration sessions, symptom improvements for depression, anxiety, and PTSD were sustained for up to five months after the last dosing session. The takeaway: ketamine alone may produce a temporary shift, but ketamine combined with therapy appears to extend and deepen those effects.

The integration window—and why it matters as much as the session itself. Ketamine acts on the brain’s NMDA receptors, triggering a cascade of neurobiological effects. Among the most clinically relevant: it increases brain-derived neurotrophic factor (BDNF) and promotes synaptogenesis—the formation of new neural connections. In plain language, ketamine temporarily makes your brain more flexible. More willing to form new pathways. More capable of updating old patterns.

Researchers call this the “neuroplasticity window.” A 2025 study in the International Journal of Molecular Sciences described this as a 24–72 hour period of heightened neural receptivity following ketamine administration—a window during which psychotherapeutic interventions may take deeper root. In practice, many clinicians extend this working window to seven to ten days, during which the brain remains in a more adaptable state.

This is where the research gets particularly relevant for our work at Catalyst Center. A peer-reviewed study published in the European Journal of Psychotraumatology (2025) examined the combination of ketamine and EMDR specifically, finding meaningful reductions in PTSD symptoms and functional impairment. The authors noted that ketamine may facilitate the adaptive updating of traumatic memories during the reconsolidation process. While this was a retrospective chart review rather than a randomized controlled trial, it represents some of the first published evidence for the KAP-EMDR combination.

Additionally, ketamine appears to decrease activity in the default mode network—the part of the brain responsible for persistent self-referential thinking and rumination. For clients who get stuck in loops of self-blame or hypervigilance, this quieting effect can create a more receptive state for trauma processing.

A word about honesty. We think it’s important to name what the research doesn’t yet show. Most existing studies are small. Many lack the randomized controlled trial design that represents the gold standard. And a 2025 systematic review from the University Medical Center Groningen noted that only two studies in the entire KAP literature have actually randomized the psychotherapy component—meaning we’re still building the evidence base for how, exactly, therapy amplifies ketamine’s effects. The clinical rationale is strong. The early results are encouraging. But this is still an emerging field, and we believe you deserve to know that.

If you’re considering this approach, here’s what the process actually looks like—because demystifying it matters.

Preparation. Before any ketamine session, you’ll work with your therapist to identify specific treatment targets, build coping resources, and set clear intentions. We don’t administer ketamine and hope for the best. Every session is embedded in a treatment plan.

In my experience, this phase does more than clients expect. Most people arrive focused on what the ketamine session will feel like — the unknown of it. What surprises them is how much clarity can surface just in the process of naming what they’re actually hoping to release. Sometimes the intention itself becomes the first real moment of the work.

The KAP session. Ketamine is administered at a sub-psychedelic dose in our office, with your clinician present throughout. Most clients describe the experience as a gentle loosening—a softening of the usual mental rigidity, not a loss of awareness. Sessions typically last two hours.

EMDR reprocessing. Within the days following the KAP session—during the neuroplasticity window—you’ll complete EMDR reprocessing with your therapist. This is where the deep therapeutic work happens. Because your brain is in a more flexible, receptive state, reprocessing can often access material that previously felt locked down or unreachable.

What I notice clinically is that clients who had been circling the same material for months — hitting the same wall — often find it moves differently here. Not because the memory changed, but because their relationship to it has.

Integration. After reprocessing, integration sessions help you make sense of what came up, consolidate new insights, and stabilize. This phase is as important as the sessions themselves.

It’s also the phase people most underestimate going in. The ketamine session feels like the event. But integration is where meaning gets made — where something that surfaced in a two-hour window gets woven into how you actually understand yourself. Clients often tell me this is where the shift becomes real.

KAP combined with EMDR tends to be most effective for clients who have already done some therapeutic work but feel like they’ve hit a ceiling. People with treatment-resistant depression, complex PTSD, or chronic anxiety that hasn’t responded fully to traditional approaches often see the most benefit.

It’s not typically recommended as a starting point for someone brand new to therapy. The work is intensive, and it requires a foundation—both a therapeutic relationship and a baseline level of emotional regulation—to be effective and safe.

There are also medical contraindications. Certain cardiovascular conditions, active substance use disorders, and some psychiatric presentations may make KAP inappropriate. Every client is evaluated individually.

The research on combining ketamine-assisted psychotherapy with EMDR is still emerging—and we think it’s important to say that clearly. We’re not in the business of overselling. What we can say is that the neurobiological rationale is strong, the early clinical findings are encouraging, and in our own practice, we’ve seen this combination open doors for clients who had been struggling for a long time.

If you’re curious about ketamine-assisted psychotherapy in Denver—whether on its own or combined with EMDR—we’re glad to talk through whether it might be a fit. That conversation doesn’t commit you to anything. It’s just a starting point.