Visual Analog Drug Effect Questionnaire (VAS) includes the following questions 1) “Do you feel GOOD effects from the drink(s)?”; 2) “Do you feel BAD effects of the drink(s)?”; 3) “Do you LIKE the effects of the drink(s)?”; 4) “Do you DISLIKE the effects of the drink(s)?”; 5) “Is this the WORST you have ever felt?”, and 6) “Is this the BEST you have ever felt?”. Subjects responded by positioning an arrow on a 100-point line anchored by “not at all” on the left and “extremely” on the right. These measures were summed to yield two scales: (a) “Positive” effects, which is the sum of “Good, Like and Best” effect responses, and (b) “Negative” effects, which is the sum of “Bad, Dislike and Worst” effects responses.
