Ketamine Therapy in Israel vs. Antidepressants

August 4, 2026

If you have taken one antidepressant after another and still feel stuck, you have probably started asking a harder question: is there something that works differently? Ketamine therapy in Israel is increasingly part of that conversation — not as a replacement for conventional psychiatry, but as a different mechanism for people whose depression has not responded to the standard path.

This article compares ketamine-assisted psychotherapy (KAP) with SSRIs and other antidepressants: how fast each works, what the evidence actually shows, how the side effects differ, and — a question we are asked constantly at our Jerusalem clinic — whether you have to come off your current medication to try ketamine.

The short answer to that last one is usually no. The longer answer is worth reading, because the two treatments are less like competitors and more like tools built for different jobs.

Why People in Israel Start Looking Beyond Antidepressants

Antidepressants help a great many people, and for most patients an SSRI remains the sensible first step. But the landmark STAR*D trial — still the largest real-world study of sequential antidepressant treatment — found that only about a third of participants reached remission on their first medication. Roughly a third did not achieve remission after two adequate trials, which is the standard clinical definition of treatment-resistant depression.

STAR*D’s often-quoted claim that around two-thirds of patients eventually remit after up to four treatment steps has itself been contested: a reanalysis using the study’s own primary outcome measure reported a substantially lower cumulative remission rate of roughly 35%. The debate is technical, but the practical takeaway is not — a significant number of people cycle through multiple antidepressants without getting well, and that experience is real rather than a personal failure.

That is the population ketamine therapy was developed for. If this describes you, our article on managing treatment-resistant depression with ketamine covers the Israeli context in more depth.

Ketamine Therapy vs. Antidepressants: The Core Differences

The two treatments differ in almost every dimension that matters to a patient — speed, mechanism, delivery, and what the side effects feel like day to day.

Onset. Antidepressants typically need four to six weeks to reach full effect. Meta-analyses of ketamine report symptom reduction within four to twenty-four hours of a single dose.
Mechanism. SSRIs work through gradual adaptation to increased serotonin availability. Ketamine acts on the brain’s glutamate system and is associated with synaptic plasticity.
How it is taken. An antidepressant is a daily tablet taken indefinitely. KAP is a short course of supervised sessions, followed by occasional maintenance.
Therapy included. Psychotherapy alongside an antidepressant is usually separate, if it happens at all. In KAP, preparation and integration therapy are built into the treatment.
Side effects. Antidepressant side effects — sexual dysfunction, weight change, sleep disruption, emotional blunting — often persist for as long as you take the drug. Ketamine’s — transient dissociation, a mild rise in blood pressure, occasional nausea — typically resolve within hours.

Speed Is the Most Striking Difference

A meta-analysis published in Translational Psychiatry found that a single intravenous dose of ketamine produced a rapid antidepressant effect peaking within 24 hours and lasting roughly three to seven days. An individual-participant-data meta-analysis in the American Journal of Psychiatry similarly found significant reductions in suicidal ideation within the first 24 hours after a single infusion.

That speed is different from anything an SSRI can offer. It is also why ketamine is best understood as a treatment that opens a window rather than one that holds a door open indefinitely.

What the Evidence Does — and Doesn’t — Say About the Therapy Part

Here it is worth being straight with you rather than promotional. A systematic review published in Psychopharmacology in February 2026 screened 768 records and analysed 11 studies of ketamine-assisted psychotherapy for treatment-resistant depression. Across those studies, KAP was associated with reductions in depressive symptoms, with some improvements sustained up to six months. But among the three studies that included control groups, KAP did not significantly outperform the control conditions, and the authors conclude that randomised controlled trials are needed before firmer conclusions can be drawn.

In other words: the rapid antidepressant effect of ketamine itself is well established. Whether the psychotherapy wrapped around it adds measurable benefit over ketamine alone is still an open research question.

What we can say is why we practise this way. Clinically, the period after a session is when people are most able to look at painful material without being overwhelmed by it, and integration is where clients tell us the change becomes usable. That is a clinical judgement supported by experience and by the direction of the evidence — not a proven superiority claim, and we would rather say so.

It is also why we deliver ketamine as assisted psychotherapy rather than as a standalone infusion. If you want to understand how that differs from a medicalized IV protocol, see our comparison of ketamine infusions and ketamine-assisted therapy, and our explainer on the neurochemistry of ketamine.

Do I Have to Stop My Antidepressants to Try Ketamine Therapy in Israel?

This is the single most common concern we hear, and the answer is reassuring: in most cases, no.

Research published in the Journal of Clinical Psychiatry found no differences in outcomes between patients treated with IV ketamine or intranasal esketamine based on which class of oral antidepressant they were taking concurrently. Practically speaking, ketamine and standard antidepressants can generally coexist.

There are specific exceptions, and they are handled at intake rather than left to chance. Some medications — benzodiazepines, ADHD stimulants, and mood stabilizers such as lamotrigine — can blunt ketamine’s effect and may require a hold on the day of treatment. MAOIs are a rule-out. Every client goes through a full medical and psychiatric intake with our psychiatrist, including a detailed review of your current prescriptions, before any treatment is approved.

The decision to change, taper, or continue any psychiatric medication belongs with your prescribing doctor. Ketamine therapy does not require you to abandon what is already helping.

Which One Is Right for You?

Neither treatment is universally better. The honest framing is that they suit different situations:

An antidepressant is usually the reasonable first step for a first episode of depression, or where conventional treatment has not yet been tried properly.
Ketamine-assisted psychotherapy is worth discussing when two or more adequate antidepressant trials have not produced remission, when side effects have become intolerable, or when the slow onset of conventional medication is itself a problem.
Many people end up using both — ketamine to interrupt an entrenched depressive pattern, and ongoing psychiatric care to maintain the gains.

What determines the right answer is not an article; it is a psychiatric assessment. Our piece on whether you are a candidate for ketamine therapy in Israel walks through the screening criteria we use, and Is Ketamine Therapy Safe? addresses the questions that usually come next.

How Ketamine Therapy Works at Our Jerusalem Clinic

Keter Health is Israel’s first ketamine-assisted psychotherapy centre, based in Jerusalem and serving clients from across the country. Ketamine is a legally prescribed medication here, and its psychiatric use is overseen by a licensed psychiatrist — in our case Dr. Isaac Nagel, MD, a board-certified psychiatrist trained at St. Luke’s Roosevelt Hospital in New York.

The structure of treatment is deliberately unhurried:

Free initial consultation. An exploratory conversation, no referral required.
Comprehensive psychiatric evaluation. Full history, medication review, and screening for contraindications.
KAP sessions. We use primarily intramuscular ketamine, administered by a medical professional alongside a KAP-certified facilitator. Most clients begin with three or four fully prepared and integrated sessions spaced over two to six weeks.
Integration sessions. Individual therapy to translate what surfaced during the session into everyday life.

Many clients then move into a lighter maintenance phase, typically one to three sessions a year. We work on a minimal-effective-dose philosophy: the least medicine needed to achieve a durable result.

FAQ

Is ketamine therapy more effective than antidepressants?
Not as a blanket statement. Ketamine acts far more rapidly, and the evidence base is strongest in people whose depression has not responded to conventional antidepressants. For a first episode of depression, a standard antidepressant is usually the appropriate starting point.

How quickly does ketamine work compared with an SSRI?
Meta-analyses report measurable improvement within 4 to 24 hours of a single ketamine dose, peaking around 24 hours. SSRIs typically require four to six weeks to reach full therapeutic effect.

Can I take ketamine and antidepressants at the same time?
Usually yes. Research in the Journal of Clinical Psychiatry found no outcome differences based on concurrent antidepressant class. Some medications may need a hold on the day of treatment, and MAOIs are a rule-out. Your intake with our psychiatrist covers this in detail.

Is ketamine therapy legal in Israel?
Yes. Ketamine is legally available for medical use when prescribed and administered by licensed professionals, and its psychiatric use is directed by a psychiatrist as part of a screened treatment plan. Read more: is ketamine therapy legal in Israel.

Will I have to stay on ketamine indefinitely, like an antidepressant?
No. Ketamine therapy is delivered as a course rather than a daily medication. Most clients complete an initial series of three or four sessions and then, if useful, return for occasional maintenance sessions.

If Conventional Treatment Hasn’t Worked

If you have given antidepressants a fair trial and depression is still shaping your life, that is worth a conversation rather than another year of waiting. We offer a free, no-obligation consultation to talk through whether ketamine-assisted psychotherapy fits your situation — and to say so plainly if it doesn’t.