Depression is diagnosed through a combination of patient self-reporting and clinical interpretation. As Dr. Karl Deisseroth mentioned on my podcast, there's a tension between the clinical and colloquial use of words. When a patient says they're "depressed," it's important to delve deeper into what they mean by that. Psychiatrists aim to understand the patient's actual feelings, moving beyond jargon to real-world examples. They might ask about the patient's outlook on the future, their level of hope, and their plans. For instance, if a patient expresses difficulty in thinking about or planning for tomorrow, it could be a sign of depression. It's a nuanced process that requires careful listening and interpretation.