Hi,
I'm working on the ADHD_200 database and I have a question about how medication status is codified
in the phenotypical data. According to the phenotypic Key document 1=
Medication naive and 2= Not Medication Naive. What does it mean when
typically developing children have a value of 2? Are they receiving some
type of medication? Also, which is the difference between NAN, -999 and
empty cells on medication status?

Thanks a lot for your time