Pharmacodynamics and Pharmacokinetics of Citalopram and Escitalopram

Inclusion Criteria

• •1. Outpatients or inpatients with nonpsychotic MDD.
• •2. A score of \>14 on the HRS-D17 (equivalent to 10 or greater on PHQ-9 which is used in primary care to assess depression) given that when medication exceeds the effect of placebo in primary care participants have a HRS-D17 \>12. We added 2 HRS-D17 points to take into account the possibility of measurement error.
• •3. Outpatients or inpatients for whom antidepressant treatment is deemed appropriate by the treating clinician.
• •4. Subjects who are between 18-85 years of age.
• •5. Participants who have general medical conditions (GMCs) which could conceivably be physiologically causing their depressive symptoms will receive treatment as usual for their GMCs as well as for their MDD.