Figure 3

Severity Dependence Scale (SDS) scores in participants with secondary chronic headache with (black) or without (dashed) medication overuse vs. contact level. χ², p < 0.0035 for all contact levels. *Primary contact level in this figure is defined as GP only (i.e. those participant with only GP contact without referral) due to illustrative purposes, to avoid overlap of groups and to allow adequate significant testing with χ2 test.