Do you mean depression is an illness? I personally don't think thats true at all, and that way of framing it usually results in people developing lifelong dependency on drugs and/or therapy, along with declining health.

Is there someone you can see that will dig into the cause(s) of your depression, whether that be C-PTSD, childhood abuse, biological disease, nutritional deficiencies, etc?

Seems to me that Pdocs, drugs, most talk therapies like CBT, and most conventional medical care all involve managing or suppressing symptoms, but do little or nothing that is curative.