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)