 Volunteers will be randomized to receive citalopram or placebo in a double blind between groups design for 7 days. They will receive the treatment capsules to take home and will be instructed to take the capsule every morning after breakfast around 8 am. Subjective mood will be assessed on each day of treatment using the Befindlichskeit scale of mood and energy, the State Anxiety Inventory and Visual Analogue Scales. Side-effects will be registered every day using a specific side-effects report sheet. 