The Mayo Clinic psychiatric pharmacogenomic team has developed a pharmacogenomic algorithm that has been designed to improve the effectiveness and safety of antidepressant medications by providing guidance in medication selection and appropriate dosing. This algorithm has been incorporated into a new genotyping interpretative report. This report is now available from AssureRx. The pharmacogenomic algorithm is based on genotyping both copies of four informative genes. These four genes are: 1) the Cytochrome P450 2D6 gene; 2) the Cytochrome P450 2C19 gene; 3) the Serotonin Transporter gene (SLC6A4); and 4) the Serotonin 2A receptor gene (5HTR2A). Though this algorithm is not yet part of the universal standard of care, Mayo clinicians have found it helpful in guiding treatment decisions at Mayo Clinic Rochester.

The proposed pilot study is designed to evaluate the clinical impact of the interpretive report in an outpatient behavioral health clinic in St. Paul, Minnesota. While the ultimate goal of this project is to show an improvement in patient outcomes, this pilot study will be used to evaluate the feasibility of introducing the pharmacogenomic algorithm to a new setting that does not routinely use the algorithm. Secondary outcome data will be collected to generate meaningful estimates of the magnitude of potential treatment effects. The study will consist of two phases, each enrolling 2530 subjects. In Phase 1, consecutive patients will be prospectively monitored to observe standard practice. Patients will be given the option to receive genotyping and those that agree will have blood drawn. However, the results of the genotyping and algorithm will not be released until all phase 1 patients have completed study visits.. Subsequently, in Phase 2, also enrolling 3025 subjects, the results of the genotyping and algorithm will be made available immediately for additional consecutive prospectively monitored patients. Patients will be prospectively monitored in the same fashion as Phase 1. The results of the study will be used to perform preliminary analyses and subsequent fully powered multi-site trials will be planned based on the results of this study.

Inclusion Criteria:

1. Patient is between the ages of 18 and 80.
2. Major depressive disorder or depressive disorder not otherwise specified (NOS) as ascertained by a physician or mental health professional licensed to diagnose.
3. Patient is an outpatient and not in imminent need of inpatient hospitalization
4. Patient's Hamilton Depression Rating score is >14
5. Patient is being seen by a psychiatrist for optimum medication management.
6. Ability to read, understand and sign an informed consent document

Exclusion Criteria:

1. Serious medical illness (as ascertained via the initial triage screening process)
2. Patients with a diagnosis of Bipolar I disorder
3. Patients with a diagnosis of Schizophrenia or Schizoaffective disorder
4. Patients who are legally unable to consent to enrollment in the study (i.e. patients with legal guardians)