Disease.

A lot of people assume that only persons with trauma from a painful accident are prone to depression, Or those who need some empathy and attention are faking depression to gain the other's care and patronage. Especially the old people like parents, grand-parents and teachers and that is because they may be lacking awareness and consciousness.

You can't blame them anyways as "depression" became the most elusive concept.

In this article, I will try to simplify this concept and will try to make it a little bit easier for everyone to understand:
- what depression is.
- what it feels like to be depressed.
- the difference between being sad and depressed.
- if it is curable or not.

It's -without controversy- a disease; almost like cancer or those diseases we never know they even exist in our bodies except through tests.
I used a cancer image as it starts growing out of no where, has no specific symptoms to indicate its existing, affecting many systems of the body and probably lethal; just like depression.

Its psychological definition is:
 "A depressive disorder is not a passing blue mood but rather persistent feelings of sadness and worthlessness and a lack of desire to engage in formerly pleasurable activities."

And this definition moves us to the difference between normal sadness and real depression.
first of all, Sadness is a tangible feeling, while depression can feel empty, like nothing at all.
They sometimes can look alike, but while we can talk about what makes us sad, depression can be unexplainable and leave us silent.
Depression keeps you stuck and fun can't fix it, instead, it isolates you from what you love,
sadness is very real difficult emotion to process, But depression is overwhelming numbness that requires professional help. 

Last but not least, depression is a curable and treatable illness but the treatment depends on the severity of the symptoms, In my opinion, you must distract your self from thinking by doing an activity that requires all your concentration and effort. 
You may also need anti-depressant medication with psychotherapy or talk therapy in which you address your emotional state.