Can Anesthesia Cause Psychosis? Factors and Symptoms

Anesthesia can trigger psychotic symptoms in a small but meaningful number of surgical patients. The range of possible mental disturbances after surgery spans from mild confusion and agitation all the way to full hallucinations, paranoia, and disorganized thinking. The exact cause of postoperative psychosis has not been pinpointed to any single factor, and the truth is that anesthesia itself rarely acts alone. Pre-existing vulnerabilities, the type of anesthetic used, the stress of surgery, and even your genetics all feed into whether your brain will react this way during recovery.

Postoperative Psychosis and Postoperative Delirium Are Not Quite the Same Thing

One of the biggest sources of confusion in this area is terminology. Doctors, nurses, and researchers sometimes use “postoperative delirium,” “emergence delirium,” and “postoperative psychosis” in overlapping ways, and the boundaries between them are genuinely blurry. Postoperative delirium is the broader, more common condition. It involves fluctuating attention, disorientation, and sometimes agitation or drowsiness. Postoperative psychosis is typically described as a more severe presentation, with hallucinations, delusions, paranoia, and profoundly disorganized behavior.

In practice, the two overlap considerably, and a patient experiencing severe delirium with visual hallucinations can look a lot like someone in a psychotic episode. The medical literature tends to treat postoperative psychosis as sitting at the extreme end of a spectrum that begins with ordinary confusion and escalates through agitation into frank psychosis. A wide range of behavioral disturbances may follow surgery, including depression, hallucinations, true psychosis, mania, and impulsivity.¹ For the purposes of this article, the factors that raise your risk and the symptoms you should watch for are relevant across this entire spectrum.

What the Symptoms Look Like

Postoperative psychotic symptoms can appear within hours of waking from anesthesia or develop over the first day or two following surgery. They tend to hit suddenly and can be deeply alarming for both the patient and the people around them. A published case of a 59-year-old woman who developed acute psychosis after gallbladder removal described her as disorganized, confused, and perplexed, experiencing a mix of auditory and visual hallucinations with a paranoid perspective.¹ She was unable to be managed without medication.

The most common symptoms include:

Visual hallucinations: Seeing people, objects, or patterns that are not there. This is more common than auditory hallucinations in postoperative settings.
Auditory hallucinations: Hearing voices or sounds. Sometimes patients describe commands or conversations that feel real.
Paranoid delusions: Believing that hospital staff are trying to cause harm, or that something sinister is happening.
Disorganized thinking: Inability to follow a conversation, jumping between unrelated topics, or appearing completely confused about where they are or what has happened.
Agitation and impulsivity: Trying to pull out IV lines, climbing out of bed, or becoming physically combative.

Not every patient presents the same way. Some become hyperactive and agitated, while others become withdrawn, quiet, and unreachable. The quiet form is easy to miss because the patient is not causing disruption, but it can be just as concerning from a medical standpoint.

Who Is Most Vulnerable

If you have no psychiatric history, are relatively young, and are going in for a straightforward procedure, your risk of developing postoperative psychosis is low. But several factors push that risk up substantially.

Pre-Existing Psychiatric Conditions

People with existing psychiatric illness face a markedly higher risk. One review found that patients with psychiatric or chronic brain illness have a three- to five-fold increased risk of delayed emergence from anesthesia and up to a 60 percent incidence of postoperative delirium.² In a study specifically looking at patients with schizophrenia, more than half experienced psychosis emergence or confusion in the first 48 hours after surgery when given a standard anesthetic regimen.³ That is a strikingly high rate compared to the general surgical population.

Advanced Age

Elderly patients are the most studied group for postoperative delirium, and for good reason. Older adults are at the highest risk of developing cognitive disturbances after surgery.⁴ An umbrella review pulling together multiple systematic reviews found that increasing age was one of the most consistent risk factors across studies, alongside pre-existing cognitive impairment, nursing home residency, cerebrovascular disease, kidney failure, and low albumin levels.⁵ The aging brain has less reserve to cope with the chemical disruption that anesthesia causes, and when you layer surgical stress on top, the system can tip over into confusion or psychosis more easily.

Substance Use and Withdrawal

Alcohol or drug withdrawal during a hospital stay is a well-recognized trigger. If you regularly drink heavily and then suddenly stop because you are nil by mouth for surgery, your brain can react violently to the absence of the substance it has adapted to. This factor is specifically listed alongside anticholinergic drugs, infections, metabolic derangements, and pain as an important precipitating cause of postoperative delirium.⁶ If you use alcohol, benzodiazepines, or opioids regularly, letting your anesthesiologist know is critical. They can plan for it.

Other Medical Risk Factors

The same umbrella review identified several additional risk factors that consistently appeared across studies: a higher overall illness burden (as measured by anesthesia risk scores), cerebrovascular disease, intraoperative blood transfusion, and low albumin levels, which is a marker of poor nutritional status.⁵ The common thread is that anything that compromises the brain’s baseline function or resilience makes it more susceptible to the disruption that comes with surgery and anesthesia.

How Different Anesthetic Drugs Affect Risk

Not all anesthetics carry the same likelihood of triggering psychiatric symptoms. The choice of drug, and the way it interacts with your particular brain chemistry, plays a real role.

Ketamine

Ketamine is perhaps the most notorious anesthetic when it comes to psychiatric side effects. It works by blocking a receptor in the brain called the NMDA receptor, which is involved in how the neurotransmitter glutamate signals between neurons. Research has shown that ketamine can reproduce symptoms of schizophrenia, including both “positive” symptoms like hallucinations and paranoia, and “negative” symptoms like emotional blunting.⁷ Brain imaging studies have linked positive psychotic symptoms to blood ketamine levels and glutamate release in a specific brain region, while negative symptoms correlated with direct NMDA receptor inhibition.⁸

Interestingly, though, the picture is not as simple as “ketamine causes psychosis.” In schizophrenic patients undergoing orthopedic surgery, a combination of ketamine with propofol and fentanyl actually reduced the rate of psychosis emergence compared to a standard regimen without ketamine, dropping it from about 54 percent to around 30 percent.³ The likely explanation is that ketamine’s analgesic and sedative properties, combined carefully with other agents, can offset its psychotomimetic effects. Context and dosing matter enormously.

Inhaled Anesthetics

The gases used to maintain unconsciousness during surgery also differ in their risk profiles. A study comparing volatile anesthetics in older surgical patients found that desflurane was associated with more than triple the odds of postoperative delirium compared to isoflurane.⁹ Sevoflurane, another commonly used gas, did not show a statistically significant difference from either isoflurane or desflurane in the same analysis. The overall incidence of delirium in that study population was 41 percent, a reminder of how common these reactions are in older patients undergoing surgery.

Regional Anesthesia as an Alternative

There is growing interest in whether avoiding general anesthesia altogether can reduce the risk. Regional and spinal anesthesia, which numb a specific part of the body while the patient remains conscious or lightly sedated, may offer advantages. One review noted that these approaches can preserve blood flow to the brain and lower neurological complication rates in patients with psychiatric illness.² The idea is straightforward: if the brain never has to process the full chemical assault of general anesthesia, it is less likely to malfunction during recovery. This is not always practical depending on the type of surgery, but for vulnerable patients, it is a conversation worth having with the surgical team.

The Brain Under Surgical Stress

Anesthesia does not act on a brain at rest. Surgery itself is a massive physiological stressor, and the brain’s response to that stress interacts with the effects of anesthetic drugs in ways that can amplify the risk of psychiatric symptoms.

Research has shown that the barrier between the bloodstream and the brain can become leaky after general anesthesia, and this breakdown may allow inflammatory molecules to reach brain tissue that is normally protected.¹⁰ Separately, elevated preoperative anxiety has been linked to higher levels of cortisol and pro-inflammatory molecules, particularly interleukin-6, which can interact with the central nervous system to increase the risk of neuropsychiatric complications after surgery.¹¹

In short, your mental state going into surgery can matter. Patients who are highly anxious beforehand tend to need more anesthetic and more pain medication, which in turn may raise the risk of postoperative mental disturbance. This is one area where preoperative counseling, managing anxiety before the day of surgery, and even short-acting anti-anxiety medications on the morning of the procedure could theoretically make a difference, though the evidence for specific interventions is still evolving.

How Long Symptoms Typically Last

Most cases of postoperative delirium and psychosis resolve within hours to a few days. The dramatic presentations, the hallucinations, the paranoia, the combativeness, tend to fade as anesthetic drugs clear the body and the brain recovers from the shock of surgery. For the majority of patients, this is a temporary and self-limiting event.

However, it is not always short-lived. Evidence shows that delirium can persist for months in some patients and is associated with poor cognitive and functional outcomes well beyond the immediate postoperative period.¹² This is especially true in elderly patients, where an episode of postoperative delirium may accelerate underlying cognitive decline. Whether the delirium itself causes lasting brain damage or simply unmasks vulnerability that was already there is debated, but either way, the episode is not something to dismiss as trivial just because the acute symptoms resolve.

Prevention and Treatment

The good news is that a meaningful fraction of postoperative mental disturbances can be prevented. Some estimates suggest that up to 40 percent of postoperative delirium is preventable with appropriate measures.¹³ Prevention begins before surgery, with identifying who is at high risk and planning accordingly.

The management approach involves several layers:

Risk assessment: Screening for cognitive impairment, psychiatric history, substance use, and nutritional status before surgery helps flag patients who need extra precautions.
Environmental measures: After surgery, simple interventions like keeping the room well-lit during the day, maintaining a normal sleep-wake cycle, ensuring the patient has their glasses and hearing aids, and providing frequent orientation cues (reminding them where they are and what day it is) all reduce the incidence of delirium.
Pain management: Undertreated pain is itself a trigger for delirium, but so is overuse of certain pain medications, particularly opioids. Striking the right balance is one of the more challenging parts of postoperative care.
Medication choices: For the anesthetic itself, the team can choose agents with lower delirium risk for high-risk patients, or use regional anesthesia where feasible. Avoiding anticholinergic medications and benzodiazepines in elderly patients also helps.

Non-drug interventions are considered the first-line approach for managing postoperative delirium when it does occur, regardless of whether the patient is agitated or withdrawn.¹³ Antipsychotic medications, such as haloperidol, are reserved for patients whose agitation poses a risk of harm to themselves or others. Environmental, supportive, and pharmacologic interventions together reduce both the incidence and the side effects of postoperative delirium.¹⁴

Emergence Reactions in Young Children

Children experience their own version of this problem, though it tends to look different from adult postoperative psychosis. Emergence delirium in children is a distinct phenomenon characterized by perceptual disturbances and psychomotor agitation that occurs most commonly in preschool-aged children shortly after waking from anesthesia.¹⁵ A child experiencing emergence delirium may thrash, scream, cry inconsolably, or not recognize their parents, and attempts to console them often make the agitation worse.

How common is it? In a study evaluating children using a validated scoring tool, about 9 percent had clinical agitation consistent with emergence delirium, though a much larger proportion (43 percent) showed at least some degree of disturbance on the scale.¹⁶ Many children who appeared agitated were actually upset for other identifiable reasons, like pain, hunger, or the presence of an IV, rather than experiencing true delirium. The distinction matters because treating pain resolves one but not the other.

Emergence delirium in children is almost always brief, resolving within 15 to 30 minutes. It does not appear to carry the same long-term cognitive risks that postoperative delirium does in elderly adults. But it is deeply distressing for parents to witness, and anesthesiologists who work with children often take steps to reduce its likelihood, such as allowing a parent to be present at induction, using certain sedative premedications, or choosing anesthetic agents known to produce smoother wake-ups.

When to Seek Help

If you or a family member develops confusion, agitation, or unusual behavior after surgery, the most important thing is to notify the medical team immediately rather than waiting it out. Most postoperative psychiatric symptoms respond well to treatment when caught early. The risk rises when symptoms go unrecognized, particularly the quiet, withdrawn form of delirium that does not cause a scene. Hospital staff are trained to screen for these changes, but family members who know the patient’s baseline personality are often the first to notice that something is off.

For patients heading into elective surgery with known risk factors (older age, psychiatric history, a history of heavy alcohol use, previous episodes of postoperative delirium), a preoperative conversation with the anesthesiologist is worth initiating. Ask about the choice of anesthetic agents, whether regional anesthesia is an option, and what the team’s delirium prevention protocol looks like. Hospitals vary widely in how systematically they screen for and manage these complications, and asking the question signals that you are paying attention.

1
PubMed. Postsurgical psychosis: case report and review of literature
2
PubMed Central. General Anesthesia in Psychiatric Patients Undergoing Orthopedic Surgery: A Mechanistic Narrative Review
3
PubMed. Anesthesia with ketamine, propofol, and fentanyl decreases the frequency of postoperative psychosis emergence and confusion in schizophrenic patients
4
PubMed Central. Post-Operative Delirium in Elderly Patients: A Narrative Review
5
PubMed. Risk factors for postoperative delirium: An umbrella review of systematic reviews
6
PubMed. Postoperative delirium. Part 1: pathophysiology and risk factors
7
The Primary Care Companion for CNS Disorders. A Case of Ketamine-Associated Prolonged Psychosis in the Perioperative Setting
8
PubMed Central. Pharmacogenetics of Ketamine-Induced Emergence Phenomena: A Pilot Study
9
PubMed Central. Volatile Anaesthetics and Postoperative Delirium in Older Surgical Patients
10
PubMed Central. The Crosstalk between the Blood-Brain Barrier Dysfunction and Neuroinflammation after General Anaesthesia
11
PubMed Central. The Burden of Preoperative Stress: Biological Mechanisms and Postoperative Outcomes
12
PubMed Central. Review articles: postoperative delirium: acute change with long-term implications
13
International Journal of General Medicine. Evidence-Based Guideline on Management of Postoperative Delirium in Older People for Low Resource Setting
14
PubMed Central. Postoperative delirium in the elderly: diagnosis and management
15
PubMed. Emergence Delirium in Pediatric Anesthesia
16
PubMed. Evaluation of emergence delirium in Asian children using the Pediatric Anesthesia Emergence Delirium Scale