The intellect devourer first appeared in the original Dungeons & Dragons game supplement Eldritch Wizardry (1976).
The intellect devourer appeared in first edition Advanced Dungeons & Dragons in the original Monster Manual (1977). The ustilagor first appeared in Dragon #69 (January 1983), and then reprinted in the original Monster Manual II (1983).
The intellect devourer appeared in third edition in the Psionics Handbook, and its 3.5 revision the Expanded Psionics Handbook (2004). The battle intellect devourer appeared in Dragon #303 (January 2003). The ustilagor appeared in Dragon #337 (November 2005).
The intellect devourer and ustilagor appeared in the fourth edition in Monster Manual 3 (2010).