They are large humanoid creatures, standing well over six feet in height and towering over Henry Townshend. They resemble a feminine monster with grotesquely distorted facial features. They have mottled gray skin with chunks missing from their bodies and wear bloody gray hospital gowns as well. They move very fluidly and lack the twitching movements common to many other monsters. They always wield pipes in their hands, with which they use to attack victims. Normally they make low-pitched breathing and growling noises, and when struck, they make grunts that sound very much like belching.
They are large, menacing opponents that attack relentlessly but slowly. They deal large amounts of damage and take an impressive amount of punishment as well. However, they are easily interrupted or avoided and can be defeated without much effort (but plenty of time) by a constant flurry of blows. They often appear in groups of two or more, making it much more difficult to defeat them. The rusty axe is the recommended method of dealing with them. Another method is to use Richard's Revolver found in his apartment in the Otherworld, as it is capable of knocking down these enemies in one or two shots.
The Patients are manifestations of Walter Sullivan's aversion to hospitals and the like, finding them terrifying as the Patients themselves are imposing. Also the bloodstains on their hospital gowns makes it seem as though they are bleeding from where their wombs should be, suggesting that they are a manifestation of Walter's hatred for his biological mother, as he seems to have taken both their lungs and wombs out. In the hospital world, Walter is seen disemboweling one by a horrified Henry, who runs away when he witnesses it.
- The Patient's facial and hair appearance resembles that of Claudia Wolf. This is especially observable during the Hospital World's intro cutscene, where Walter is seen "operating" on one.