"my initial qbtest score was 99. i was prescribed vyvanse 20mg but was supposed to be taking 3/day. i misunderstood and only took 1 early in the morning on the day of my follow up test. i have nuvigil that i take occasionally for shift work sleep disorder. i took one to help stay alert on my afternoon drive to the follow up test. my qbtest score dropped from 99 to 12. i am sure that the nuvigil is responsible because the vyvanse was taken at the lowest dose and several hours outside the time window."