Drugs such as Adderall or Ritalin are in high demand at colleges, whether to use or sell to others. For actual patients, these medications calm them down, but those faking ADHD become hyper, energized and focused.
The study, published in the journal Psychological Assessment, tested students who actually had ADHD but weren't on their medication and students who had been asked by the researchers to pretend that they had the disorder. It turns out, self-report checklists for ADHD were of "no value" in figuring out the fakers. Even someone with a "cursory knowledge of the disorder could simulate the symptoms."