When Ketamine Wears Off: A New Way to Keep Suicidal Thoughts at Bay

For people with severe depression and suicidal thoughts, ketamine can bring relief within hours. That rapid effect has transformed the way we think about treating psychiatric crises. But for many patients, the benefit is temporary. Within days to a couple of weeks, suicidal thoughts often begin to return, creating a difficult gap between immediate crisis relief and longer-term recovery.

A study published this May in the American Journal of Psychiatry suggests researchers may have found a way to keep that relief going longer.

A Quick Refresher on Ketamine

Ketamine has become one of the most important advances in psychiatry for treating severe depression and acute suicidal ideation. Unlike traditional antidepressants, which often take several weeks to become effective, ketamine can reduce depressive symptoms and suicidal thinking within hours.

The FDA-approved nasal spray version, esketamine (Spravato), is approved for adults with major depressive disorder and acute suicidal ideation or behavior as part of a comprehensive treatment plan. While ketamine’s rapid antidepressant effects are well established, one of its greatest challenges is durability. The initial improvement often fades, requiring repeated treatments or additional strategies to maintain the benefit.

For years, ketamine’s effects have been explained primarily through its actions on the brain’s glutamate system, particularly its ability to block NMDA receptors and promote rapid synaptic plasticity. Over the past several years, researchers have begun to suspect that another system may also play an important role: the brain’s endogenous opioid system.

That possibility has opened an entirely new line of research.

Why the Opioid System?

When most people hear the word “opioid,” they think of pain medications or addiction, but the brain’s own opioid system serves a much broader purpose.

Endogenous opioids help regulate emotional pain, stress, attachment, reward, and our sense of psychological well-being. Some researchers believe that dysfunction within this system may contribute to the intense emotional suffering that accompanies major depression and suicidal thinking.

Several studies have suggested that ketamine’s antidepressant and anti-suicidal effects may depend, at least in part, on activation of the brain’s mu-opioid receptors. Rather than acting through glutamate alone, ketamine may be engaging multiple brain systems that work together to produce rapid relief.

If that’s true, an obvious question follows: could supporting that opioid pathway after ketamine help extend its benefits?

What the New Study Found

Researchers at Stanford enrolled 50 adults with major depressive disorder and clinically significant suicidal ideation.

Every participant first received a single intravenous ketamine infusion. Two days later, participants were randomly assigned to receive either very low-dose sublingual buprenorphine (0.2–0.8 mg daily) or placebo for the next four weeks.

The results were encouraging.

By the end of four weeks, participants receiving buprenorphine showed a 76% reduction in suicidal ideation scores, compared with a 43% reduction in the placebo group. While both groups improved initially, much of the placebo group’s benefit had diminished by the end of the study. In contrast, patients receiving buprenorphine largely maintained their improvement throughout the four-week treatment period.

Importantly, this was a randomized, double-blind, placebo-controlled trial—the gold standard for clinical research. Although relatively small, it is the first study to demonstrate that a medication may meaningfully prolong ketamine’s anti-suicidal effects.

Wait… Isn’t Buprenorphine Used for Opioid Addiction?

Yes, and that’s part of what makes these findings so interesting.

Buprenorphine is best known as one of the most effective medications for treating opioid use disorder. It works as a partial agonist at the mu-opioid receptor, meaning it activates the receptor but only to a limited degree. This “ceiling effect” greatly reduces the risk of respiratory depression and produces far less euphoria than traditional opioid medications.

In this study, researchers used doses between 0.2 and 0.8 mg daily—far lower than the doses typically prescribed for opioid use disorder. Participants generally tolerated the medication well, and no new safety concerns emerged during the study.

The idea was straightforward: allow ketamine to rapidly interrupt the suicidal crisis, then use low-dose buprenorphine to help sustain the underlying biological pathways that may be contributing to that improvement.

Why This Matters

One of the greatest challenges in treating suicidal patients isn’t simply helping them feel better today; it’s helping them stay better long enough for therapy, medication adjustments, and life circumstances to begin making a lasting difference.

Ketamine opened an entirely new chapter by demonstrating that suicidal thoughts can improve within hours rather than weeks.

This study suggests we may now be asking the next important question: how do we make that improvement last?

If future studies confirm these findings, clinicians may eventually have a way to bridge the vulnerable period after ketamine treatment, reducing the likelihood that suicidal thoughts quickly return.

A Few Important Caveats

As promising as these findings are, it’s important to keep them in perspective.

This was a single-center study involving only 50 participants. Larger, multi-site studies will be needed before this approach becomes part of standard clinical practice. Researchers will also need to better understand which patients benefit most, how long treatment should continue, and what the long-term risks and benefits may be.

For now, this combination should be considered an emerging research strategy—not an established treatment protocol.

Anyone experiencing suicidal thoughts should seek immediate evaluation from a qualified mental health professional. Decisions about ketamine, esketamine, or buprenorphine should always be made within the context of comprehensive psychiatric care.

The Bottom Line

Ketamine fundamentally changed the treatment of suicidal depression by proving that relief doesn’t always have to take weeks.

This new research suggests the next breakthrough may not be finding a faster treatment but finding a way to preserve the relief that ketamine already provides.

It’s too early to know whether low-dose buprenorphine will become part of routine psychiatric care, but the biological rationale is compelling, the study was carefully designed, and the results are difficult to ignore.

In a field where sustained treatments for suicidal crises remain limited, that’s an important development

and one well worth watching.