[Headache and transformed migraine with medication overuse: what differences between disability, emotional distress...

Twelve percent of general population is estimated to suffer from migraine (Henryet al., 2002), which represent in France 6 to 7 millions of individuals. Transformed migraine (TM) with medication overuse is a complication of migraine characterized by an increase of crisis frequency and by a parallel increase of medication intake. French prevalence of TM with analgesic overuse seems to reach up to 3% of general population (Lanteri-Minet, 2003). TM is associated with an increased disability (concerning housework, leisure, job and social activities). Moreover TM is associated with a bad emotional adjustment, which can lead to anxiety and depressive disorders. Those disorders have been founded to be more frequent in TM than in simple migraine (Radatet al., 1999). As a consequence, TM patients's quality of life is severely impaired. The use of dysfunctional coping strategies against pain should explain bad emotional adjustment in those patients. One study have found a statistical relationship between dysfunctional coping strategies such as nd depressive disorders in migraineurs (Materazzo et al., 2000).

The aim of this study was to compare 30 simple migraineurs (SM) to 32 transformed migraineurs with medication overuse (TM) for impairment, emotional adjustment and coping strategies. Patients have been assessed with Pain Disability Inventory (PDI) (Pollard et al., 1984), Hospital Anxiety Depression scale (HAD) (Zigmond and Snaith, 1983) and Coping Strategies Questionnaire (CSQ) (Rosentiel and Keefe, 1983).

Principal Component Analysis (SPSS Software) confirms the good psychometric properties of PDI and HAD in headache patients. Statistical analysis shows higher emotional distress scores (HAD mean score = 32,2 +/- 10,9) in TM than in SM (24, 1 +/- 7,3) (p < 0,001). Both groups didn't use the same coping strategies against pain. TM were characterized by the use of "dramatisation", "distraction" and "pray", which are considered as dysfunctional coping strategies, although SM used "reinterpretation" which is associated with a better adjustment in term of disability and emotional distress (Riley et al., 1999).

These results suggest that dysfunctional coping strategies in TM should explained the increased prevalence of emotional distress in this population. It should be of an utmost interest to assess temporal evolution of coping strategies after medication withdrawal. Withdrawal is the main therapeutical measure proposed to TM patients. It should also be supposed that behavioural changes related to medication with drawal evolve in parallel with changes in the use of coping strategies against pain.