text:  There's no single definition of microdosing, but Kilmer says it tends to be in the range of one-tenth to one-twentieth of a full dose. The top reasons people gave for trying it? Fun and social enjoyment, mental health, and personal development. These results from RAND dovetail with another study published in JAMA Health Forum by epidemiologist Eric Leis and his team at the University of California, San Diego.