1. Neuroscience Unit, Conci·Carpinella Institute, Córdoba, Argentina
2. Hospital das Clínicas, University of São Paulo, São Paulo, Brazil
3. Centro de Pesquisa Clínica e Epidemiológica, Hospital Universitário, Universidade de São Paulo, São Paulo, Brazil
4. Headache Group, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
5. Danish Headache Center, Rigshospitalet Glostrup, University of Copenhagen, Denmark
6. Instituto de Psiquiatria, Hospital das Clínicas, Universidade de São Paulo, São Paulo, Brazil