Presynaptic Imaging in Major Depressive Episodes After COVID-19

Inclusion Criteria: * New onset MDE within 3 months after mild or moderate COVID-19, with MDE verified by the research version SCID for DSM 5. See "Positive COVID-19 diagnosis" listed after inclusion/exclusion criteria for a description of how this is determined. * Age 18 to 75. * Good general physical health with no active medical conditions based on self-report (except migraine or PASC). Exclusion Criteria: * Use of antidepressants in the previous month (6 weeks for fluoxetine). * Use of stimulant medication affecting dopamine release in the previous month * Use of antipsychotics in the previous month * History of neurological disease (except migraine, and PASC) based on self-report * Use of medications or herbal products or natural health products with central nervous system effects in past 2 weeks based on self-report * Presence of cigarette smoking in the past two months, based on self-report * Lifetime diagnosis of severe Substance or Alcohol Use Disorder, or diagnosis of mild to moderate Substance or Alcohol Use Disorder in the past two years, based on self-report and verified by the Research Version of Structured Clinical Interview for Diagnostic and Statistical Manual-5 (SCID-5-RV) * Use of recreational drugs, including marijuana, in the past two months, based on self-report and verified by the Research Version of Structured Clinical Interview for Diagnostic and Statistical Manual-5 (SCID-5-RV) * Positive urine drug or cotinine screen at any timepoint during the s…