Summary
The duration of ketamine-induced psychosis can vary greatly depending on individual factors. However, acute psychosis symptoms typically subside within an hour after taking the drug. In some cases analyzed in the review, psychosis may persist for a week or longer. It's crucial to seek medical attention immediately if experiencing symptoms of psychosis and avoid taking ketamine outside of medical settings.
What is Ketamine Used For?
Ketamine is a fast-acting antidepressant used to combat acute suicidal thoughts and treatment-resistant depression. It activates excitatory NMDA receptors throughout the central nervous system and has traditionally been used for inducing anesthesia [1] .
Ketamine misuse is also commonly seen at raves as a white powder or nasal spray. Taking ketamine outside of medical use can have detrimental effects.
Ketamine is a Schedule I substance that must not be taken outside of careful medical supervision.
Ketamine-Induced Psychosis
First of all, it is critical to understand what ketamine-induced psychosis is. Psychosis is a group of psychiatric symptoms, commonly referred to as psychotic symptoms. These can be grouped into positive and negative [2]. Positive symptoms include hallucinations, delusions, dissociative effects or distortion of language. Negative symptoms include depression, inability to begin tasks, disorganization, apathy, and reduced need for socialization [3]. Both positive and negative symptoms of psychosis were increased after giving ketamine to health volunteers and people with schizophrenia [2].
How Long Does Ketamine-Induced Psychosis Last?
We have established that ketamine can increase both positive and negative symptoms of psychosis. The critical question is, how long do these last? Are they transient, meaning that they subside naturally? At what point should you be worried about persisting psychosis?
First of all, the duration of ketamine-induced psychosis or psychotic symptoms can vary significantly between individuals. They can depend on multiple factors, such as the dose of ketamine used, the individual's mental health history, and their physiological response to the drug.
In some studies, ketamine has been shown to induce a dose-related, short-term worsening in mental status in individuals with schizophrenia, with psychotic effects lasting less than 30 minutes [4]. However, several subjects in the same study evidenced delayed or prolonged psychotomimetic effects such as worsening psychosis with visual hallucinations lasting 8-24 hours [4].
A Meta-Analysis of Ketamine-Induced Psychosis Duration
The meta-analysis encompassed 17 studies with 458 participants, focusing on those with major affective disorders treated with intravenous (IV) ketamine at doses of 0.4 or 0.5 mg/kg [5]. The primary tool for measuring psychotic symptoms was the Brief Psychiatric Rating Scale – positive symptoms (BPRS+). Here’s a summary of the findings:
- Initial Symptom Spike: In 72% of the studies, significant increases in BPRS+ scores were observed within the first 30–60 minutes post-infusion. However, these increases were generally mild and temporary.
- Rapid Return to Baseline: Symptom severity typically returned to baseline levels within 60 minutes post-infusion, with no evidence of recurrence in the subsequent hours and days.
- Heterogeneity in Results: While there was significant variability between studies, the overall trend suggested that psychotic symptoms induced by ketamine were transient and resolved quickly.
- Safety Profile: No major psychiatric adverse events or distressing psychotic symptoms were reported. The side effects were mild and similar to those observed in medical and cognitive domains.
So What?
These findings provide reassurance regarding the use of ketamine in treating major depressive disorders. The transient nature of the psychotic symptoms observed suggests that, with proper monitoring, ketamine can be a safe option for patients. However, the significant variability between studies underscores the need for individualized patient assessment and cautious administration.
Summary: How Long Does Ketamine-Induced Psychosis Last?
Ketamine, administered for therapeutic purposes at 0.4 or 0.5 mg via IV infusion, appears to have a mild and temporary side effect profile concerning psychotic symptoms. These findings bolster confidence in ketamine’s potential as a rapid-acting treatment for depression, provided that patients are carefully monitored for psychotic symptoms post-infusion. However, the duration of psychotic symptoms may differ if ketamine is taken intranasally or orally.