Anesthesia can cause disturbing sexual hallucinations, leading to lasting psychological trauma

Having witnesses or recording devices during procedures that require anesthesia could help prevent opportunities for sexual assault.

Some patients may experience vivid and detailed sexual hallucinations during anesthesia with sedative-hypnotic drugs such as propofol, midazolam, diazepam, and nitrous oxide. Some make suggestive or sexual comments or act out, such as grabbing or kissing medical professionals or touching themselves sexually. Others wake up mistakenly believing they have been sexually assaulted. Why does this happen?

Doctors have long known that sedative-hypnotic drugs, which slow brain activity to induce calmness or sleep, can affect a patient’s perception of reality. A 1984 review of the drugs midazolam, ketamine and thiopental found that 18% of patients undergoing anesthesia for a dental or medical procedure had difficulty distinguishing reality from fantasy during and immediately after dosing. Similarly, a 1980 study found that approximately 14% of patients report dreams or sexual arousal while under anesthesia. Not surprisingly, together these two features of anesthesia can sometimes manifest themselves in sexual hallucinations.

There have been rare instances where medical professionals have used a patient’s unconscious state to commit sexual assault. For example, in 1991, a medical worker sexually assaulted a college student under anesthesia. Although the case was initially dropped on the grounds that the patient might have been having a drug-induced sexual hallucination, the genetic evidence the health professional left behind later led to his conviction. It cannot be assumed that all cases of sexual assault reported under anesthesia are due to a sexual hallucination.

We are pharmacology researchers who recently reviewed the medical literature on sexual assault or sexual fantasy during anesthesia from the first documented case to February 2023, finding 87 reported cases from 17 published articles. A better understanding of what triggers unpleasant or sexual dreams under anesthesia could help researchers figure out how to reduce the risk of hallucinations to protect both patients and providers.

Reports of hallucinations

Sixteen of the individual cases we encountered in our review involved patients reporting sexually amorous behavior or alleged sexual assault. In these cases, observers such as caregivers or family members were also present during the procedure, reducing the chance that the sexual behavior actually occurred versus the hallucination.

We also found a striking match between the anatomical location of the procedure and where the patient perceived inappropriate sexual contact. Procedures involving the mouth were perceived as oral sex, squeezing a ball to make a vein more accessible as squeezing a penis, chest procedures such as breast fondling, and groin procedures such as vaginal penetration.

This may explain why an evaluation of 200 patients found no cases of sexual hallucinations for those who had gallbladder or appendix procedures involving the abdomen, but about 12% of those who had vaginal procedures you have noticed amorous or sexually uninhibited behavior.

These effects of anesthesia can have major real-world impacts on patients and providers long after surgery.

The emotional turmoil a patient experiences is likely to be the same whether they are actually sexually assaulted under anesthesia or have vivid hallucinations of the event. And practitioners can feel heartache, too: Some medical professionals accused of actual or alleged sexual assault have been taken before regulatory boards or courts and lose their license to practice.

Necessary protections

It is possible that if patients knew that a hallucination of sexual assault is a rare but possible adverse effect of anesthesia before receiving it, and were aware of the steps health care professionals are taking to reduce that risk, they would be less likely to believe the their gender the hallucinations were real. But that wouldn’t lessen the trauma of the hallucination.

In one case, an anesthesiology student volunteered in a study in which she experienced sexual hallucinations after taking sedative-hypnotics. Although she knew her vivid memories of the sexual assault were not real, the anguish she felt about them led her to withdraw from the study.

In our literature review, we found 71 individual cases where the physician was alone with the patient at the time of the alleged sexual assault or sexual behavior. For the safety and well-being of both patients and medical professionals, having witnesses in the room or recording devices during dental or medical procedures could help prevent an opportunity for sexual assault and reassure patients that any hallucinations they may be experiencing are not real.

However, the healthcare system must go further to protect patients. Patients dealing with the trauma of hallucinated sexual assault, even if there is evidence that it did not actually occur, should be referred for counseling and supported just like someone who has been physically harmed during a medical or dental procedure.

They remain unknown

What makes some people more likely to remember their dreams while under anesthesia is unclear. A 2009 study of 97 propofol-treated patients reported that those who frequently recall their dreams after anesthesia received higher doses of anesthetics, were younger than 50, and took longer to recover from anesthesia. A 2013 study of 200 propofol-treated patients found that men were more likely to recall dreams after anesthesia, but women were more likely to recall unpleasant dreams. While dreams and hallucinations are related experiences, people who experience hallucinations believe they could conceivably be real.

While we have reviewed all published cases of sexual hallucinations in the medical literature, the actual incidence of anesthesia-induced sexual hallucinations remains unknown. Given the decades since the first reported cases, more work needs to be done. Data from a very large sample of patients will be needed to understand the prevalence of sexual hallucinations under anesthesia. However, pharmaceutical companies are reluctant to spend money on research that could prove their drugs cause adverse side effects.

Finally, although we limited our review to reports of sexual hallucinations during anesthesia, millions of Americans use other sedative-hypnotic drugs. Benzodiazepines such as alprazolam (Xanax) and temazepam (Restoril) are used to treat anxiety and induce sleep. Z-drugs such as zolpidem (Ambien) and eszopiclone (Lunesta), as well as suvorexant (Belsomra) and sodium oxybate (Xyrem) are also used to induce sleep. Opioids such as morphine and oxycodone and gabapentinoids such as gabapentin (Neurontin) and pregabalin (Lyrica) are used to treat pain. Muscle relaxants such as carisoprodol (Soma) and cyclobenzaprine (Flexeril) are used for muscle spasms. All of these drugs have reported cases of patients experiencing hallucinations while taking them.

In a review of the FDA’s adverse event reporting system, which public health officials and researchers use to monitor drug safety, 30,728 cases of abnormal dreams were reported from 1974 to 2022. Most were on sedative-hypnotic drugs that treat insomnia, anxiety, pain and muscle spasms. The reports do not specify the nature of these dreams, or how they affected patients’ perceived well-being.

It is important for patients to be aware that abnormal dreams are a possibility when starting sedative-hypnotic treatment and to inform their doctor if they experience hallucinations. These symptoms may indicate that the drug is not the right choice for you or that the dose may be too high.

This article is republished from The Conversation, an independent, non-profit source of news, analysis, and commentary from academic experts, under the Creative Commons license.