When you think about what depression is, you probably first think about its psychological symptoms: sadness, decreased motivation, fatigue, etc. Most of us think of depression as a psychological disorder, but there is a large body of evidence that suggests that depression might actually be a biological disorder, as much so as diabetes. 

If you've taken a psychology class, you might also think of decreased levels of neurotransmitters like dopamine and serotonin, but what makes these neurotransmitter levels low in the first place? How do they connect to psychological symptoms of depression? And what does ketamine, a psychoactive drug, have to do with depression? Dr. Gerard Sanacora, the principal investigator of Yale Medical School's Depression Research Program, talks about the latest research on the underlying biological mechanisms of depression and how this knowledge is being applied to discover new treatments for depression. 

Host & Audio Editor: Kevin Bao

Helpers: Serene Feng and Daewon Kwon