Patients, who previously received intravenous ketamine, will be asked to provide genetic samples in order to assess relationships between response and genetic markers.

Patients will provide two saliva swabs containing genetic materials.

Genetic markers associated with metabolism of IV ketamine will be assessed

The QIDS-SR16 is a self-report assessment used to evaluate depression severity in patients with a Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, diagnosis of Major Depressive Episode. In total, there are 16 individual questions evaluating 9 DSM domains. The highest score is 27, indicating severe depression, while the lowest score is 0, which would suggest a complete absence of depressive symptoms.

The GAD-7 is a 7 item self-report assessment used to evaluate symptoms of anxiety. The scale ranges from 0 (not at all) to 3 (nearly every day). To total score ranges from 0 suggesting a lack anxiety symptoms to 21, indicating severe anxiety.

The SHAPS assessment is a 14 item self report tool used to measure anhedonia. Each item can be have a response of 1 (Definitely agree), 2(Agree), 3(Disagree), and 4(definitely disagree). The total score ranges from 14 to 56, in which higher scores on the assessment indicate higher levels of anhedonia.

The SDS contains 3 items, each ranging between zero to ten. The SDS is a self-reported assessment of disability within the context of depression. The total score ranges from 0, indicating no impairment, to 30, indicating severe impairment.

WPAI is a questionnaire used to evaluate lost productivity due to depression. scores are presented as percentages (multiplying the scores by 100), with 0% representing no impact on productivity and 100% representing complete impact on productivity.