Inclusion Criteria:  18-80 years of age PHQ-9 score ≥ 10  Suffer from Major Depressive Disorder meeting DSM-V criteria and meet at least one of the following:  Either new to antidepressant treatment or currently taking medication for less than 6 weeks. Inadequate efficacy after at least 6 weeks of antidepressant treatment Have discontinued antidepressant treatment due to adverse events or intolerability within the last 6 weeks Must be able to understand requirements of the study and provide written informed consent (English or Spanish)  Exclusion Criteria:  Any patient for whom providing a buccal swab sample would be contraindicated or not possible. Patients taking antidepressants for > 6 months consecutively prior to baseline unless determined to be inadequate efficacy and PCP looking to change medication. Subjects diagnosed as not having or depression. Patients with history of prior PGx testing Inability to provide informed consent Current diagnosis of bipolar disorder type I or II, psychosis, schizophrenia and/or schizoaffective disorder Inability to attend scheduled study visits Patients who are known to be pregnant or lactating Patients that are diagnosed with severe depression