Dissociation: Ketamine and Other Dissociative Experiences

Plain-language meaning

In this library, "dissociation" means a feeling of being detached from your body, your surroundings or your own thoughts. It is a recognized effect of dissociative drugs such as ketamine and PCP. It is described differently from the experience of a classic psychedelic such as psilocybin or LSD. This page is information only and does not suggest using any substance.

Evidence labels used here: approved medicine (regulator and indication named), mixed and insufficient evidence.

Dissociative versus classic psychedelic

The National Institute on Drug Abuse (NIDA) groups these drugs by how they act in the brain. [1]

Table source: NIDA. [1] NIDA lists MDMA, ibogaine and salvia as "other drugs" that work in a variety of ways. [1] The two groups overlap in what people report, and NIDA notes that researchers debate how to describe and classify them. [1] Never assume that what is true of one substance is true of another.

Ketamine and esketamine are not the same product

Esketamine nasal spray is an FDA-approved prescription medicine. Label: approved medicine (US FDA; treatment-resistant depression in adults, and depressive symptoms in adults with major depressive disorder and acute suicidal ideation or behavior). [2] NIDA says ketamine itself is not FDA-approved for any mental health disorder, though clinics offer it off-label. [3] Ketamine is the racemic mixture of two forms, and esketamine is one of them. [2]

What the FDA label says about dissociation

• The label carries a boxed warning for sedation, dissociation, respiratory depression, abuse and misuse, and suicidal thoughts and behaviors. [2]
• The most common psychological effects were dissociative or perceptual changes, including distortion of time, space and illusions, and derealization and depersonalization. Between 61% and 84% of treated patients developed them, measured on a clinician-administered scale. [2]
• In clinical trials dissociation was transient and occurred on the day of dosing. [2]
• Because of these risks, patients must be monitored by a healthcare provider for at least 2 hours per session, and the medicine is only available through a restricted program (a REMS). [2]
• The label says to assess patients with psychosis carefully before treatment, and to treat only if benefit outweighs the risk. [2]

Is dissociation part of how ketamine works?

This is mixed, and not settled.

• A secondary analysis of 108 treatment-resistant inpatients who received a single ketamine infusion found that more dissociation 40 minutes in was linked to more improvement in depression scores at 230 minutes and at day 7. The authors list limits: secondary analysis, combined diagnostic groups and possible unblinding. [4]
• A recent systematic review of 122 studies (searches run to November 2025) looked at 77 possible predictors of response to ketamine and esketamine, including dissociation. Most variables had more reports of no association than of a positive or negative one. [5]

Association with response is not proof that dissociation is needed. See proposed mechanisms vs proven clinical outcomes and treatment-resistant depression evidence.

Other reported effects of ketamine

NIDA lists short-term side effects of ketamine such as headache, dizziness, sleepiness, feeling "loopy", difficulty speaking, numbness, blurred vision or nausea, plus changes in blood pressure and heart rate. [3] It says unsupervised ketamine use may have serious health risks. [3]

Safety note

Dissociation can impair judgment and coordination. The esketamine label says patients should not drive or operate machinery until the next day after a restful sleep. [2] If someone is unresponsive, has trouble breathing or is in danger, call 911 (US). US Poison Help is 1-800-222-1222 (see poison help by country). See also dissociatives and ketamine.