Table 1.

The five questions of the Severity Dependence Scale (SDS) adapted for headache medication

1	Do you think your use of headache medication was out of control? (never/almost never = 0, sometimes = 1, often = 2, always/nearly always = 3)
2	Did the prospect of missing a dose make you anxious or worried? (scoring as for question 1)
3	Did you worry about your use of your headache medication? (scoring as for question 1)
4	Did you wish you could stop? (scoring as for question 1)
5	How difficult would you find it to stop or go without your headache medication? (not difficult = 0, quite difficult = 1, very difficult = 2, impossible = 3)

“Your headache medication” was in the interview replaced with the name of the individually relevant headache medication. Each item is scored on a 4-point scale (0–3), and the total maximum score is 15