Why does clinical depression need to be treated?

Depression: One very frequent symptom of depression is suicidal thoughts. Sometimes this progresses to the patient attempting suicide. We have found that treatment through a combination of medications and talk therapy helps people manage their depression, which prevents suicide and allows people to live a higher quality of life (be happy), be present for their family, and be healthier overall.

Clnical depression: Because, it's miserable to be depressed on an ongoing basis, isn't it? Would someone choose to continue to suffer if there were an alternative available that can lead to increased happiness? If it's clinical depression, chances are it may not resolve on its own, without professional help.