I was an ISTJ when I was on Adderall..and before Adderall I was an "INTJ" and now that I've been off a while, I'm still an "INTJ."
I've taken the test a million times, the majority of the time, I get "INTJ"..It seems to suit me better than being an ISTJ, most ISTJ's I know are completely predictable and they're all "rule abiding, good citizen" type people. That isn't me in the slightest.