The Arizona Daily Star is reporting that doctors are being warned that some general anaesthetics are associated with sexual dreams which some people may remember as real.
Although it is almost impossible to verify how often sexual hallucinations occur, some studies indicate it happens in 1 percent to 3 percent of anesthetized patients, Strickland said. With some anesthetic drugs – such as ketamine or propofol – the incidence is up to 5 percent.
Just why it happens is not well understood. But the risk is higher under lighter, sedating anesthesia than under deep anesthesia, doctors have found.
Link to article from Arizona Daily Star (via BoingBoing)
Links one and two to cases on PubMed.