Psycho-biological Substrates of Therapeutic Benefit of Thermal Cure on Generalized Anxiety Disorders

Inclusion Criteria: * Diagnostic of generalized anxiety disorder according to the Diagnostic and Statistical Manual of Mental Disorders (DSM IV) * No treatment by antidepressant for at least 2 months * No treatment by anxiolytic/neuroleptic/bete blockers/antipsychotic for at least 3 weeks * Global score of Hamilton Anxiety Scale (HAM-A) is greater or equal to 20 * Score of HAM-A symptoms greater or equal to 8 * Score of Hamilton Depressive Scale (HAM-D) lower or equal to 7 * Age: Participants will be males and females, 18-75 years of age included. * For women, no ongoing pregnancy/ negative pregnancy test * No wounds * Affiliation to a social security system (recipient or assignee) * Signed written inform consent form Exclusion Criteria: * Treatment by antidepressant for at least 2 months or a treatment by anxiolytic, neuroleptic for at least 3 weeks * Psychotropic treatment (antidepressant, anxiolytic and neuroleptic) between the preinclusion and inclusion * Psychotherapy during the 3 months prior to the inclusion * Thermal cure during the 6 months prior to the inclusion * Treatment by paroxetine for at least 1 month with dose equal or superior to 20 mg per day during the 12 months prior to the inclusion * Contraindication to paroxetine * Enhanced protection (minors, pregnancies women, nursing women,people deprived of liberty by administrative or judicial decision, ...) * Blood donation during the 3 months prior to the inclusion