Humans fail to understand the world around them and alsofail to recognize this lack of understanding. The illusion ofexplanatory depth (IOED) exemplifies these failures: peoplebelieve they understand the world more deeply than theyactually do and only realize that this belief is an illusion whenthey attempt to explain elements of the world. An unexploredfactor of the IOED is how people may become overconfidentby confusing their own understanding with others’understanding. In two experiments, we examine the IOED inmental disorders, a domain where society has a limitedunderstanding. In Experiment 1, we demonstrate that peopledisplay an IOED for mental disorders as well as devices, butthat it is smaller for mental disorders. In Experiment 2, weshow that exposing the IOED is specifically linked togenerating an explanation, rather than more generallythinking about a phenomenon.