The PLISSIT model, also known as the PLISSIT model of sex therapy,[1] is a modeling system used in the field of sexology to determine the different levels of intervention for individual clients. The model was created in 1976 by Jack S. Annon. The letters of the name refer to the four different levels of intervention that a sexologist can apply: permission (P), limited information (LI), specific suggestions (SS), and intensive therapy (IT). The model is also used outside the field of sexology, especially in fields involving extensive or life-threatening surgery.[2]