Depression is a very unspoken illness of our time.
Oyeah! Depression is a state of low mood and aversion to activity that can affect a person's thoughts, behavior,,and attitude
Some depressed people commit suicide.
Yeah ,they need to be subjected to a Suicide risk assessment a process of estimating probability for a person to commit suicide
Sometimes people will lie about it, so screenings don't always work.
That's would not help the victim ,mood is also a symptom of some mood disorders such as major depressive disorder 
I think doctors just try to heal the symptoms but are not looking at the causes enough.
Sure ,if not properly checked .,it may.long lasting feelings of sadness and loss of interest.