(Incomplete, of course, but there would ALWAYS be more to add. Not even getting into bipolar disorder, either, just depression.)
*Clinical/Chemical Depression, as a medical condition, is not the same thing as “feeling sad,” or being “down.” Living through and dealing with normal sadness is an essential part of the human experience. Although depression is called a mood disorder, the clinical meaning of “mood” is not necessarily the same as in colloquial speech.
*A clinically depressed person may or may not even feel especially “sad” at any given time. It’s like, alcohol is classified as a depressant, but that doesn’t mean having a few beers will necessarily make you feel sad. Rather, your brain actually functions differently during a depressive episode. This can take many forms, but in general, you will tend to process things more slowly, and your ability to feel things goes completely out of whack,
*One symptom of depression is the absolute inability (or at least attenuated ability) to experience joy, or motivation, or in some cases to feel much of anything at all. Not a lack of desire to, but an inability. Win the lottery? Numb. New baby? Numb. Diagnosed with terminal cancer? Numb. Hungry? Meh, the kitchen is too far away. Easier to starve.
*Sometimes when a person with depression “acts out,” or does something “crazy,” it is in a desperate attempt to feel something. ANYTHING at all.
*The flip side
I work later today. Is there any way I can call in sad?