Humans use anesthetic to make the blindingly painful and mentally scarring experience of having your eyes sliced open, viscera exposed, or limbs hacked off more tolerable. This is accomplished by inducing unconsciousness in the patient.

Since yinrih can't lose consciousness, they've had to come up with other ways to not give patients PTSD. The most straightforward way is by making surgery less invasive. Micro Mechs have already been mentioned. The fixed external surgical robots that healers use to avoid the hygiene issues that accompany their four-legged body plan are also designed to be as minimally invasive as possible. Many surgical procedures thus be carried out with the application of a local analgesic. Additionally, some operations can be performed during the patient's torpor period when the nervous system is less responsive to external stimuli. But what if you're amputating a limb? There's no way to do that with anything approaching subtlety. The answer is simple: send the patient on a wild drug trip! Psychedelic drugs are the only way outside of suspension to prevent a patient from processing the intense pain signals generated by invasive surgery.

There's a thriving black market for this so-called mind candy, and addiction is prevalent among healers. The illicit use, possession, distribution, and manufacture of mind candy is subject to severe punishments in most jurisdictions. The Spacer Confederacy is perhaps the only exception, though individual colonies like Wayfarers' Haven may still penalize these actions.