I do think that emotions must be subject to the will and not the other way around, which leads to problems. 

I also think that we don't teach children how to manage disappointment, that they are not entitled to have everybody like them or for everything to go their way in life. If they are sheltered from learning this when younger, learning it when older is going to be much more difficult. 

Where I disagree is that brain chemistry being out of whack is definitely a thing. One who is clinically depressed can benefit enormously from medication and psychotherapy. 

Of course there is a spiritual component too and faith can keep one grounded and resilient, as does the knowledge one's life belongs to God and it is not ours to dispose of at will and that we have obligations to others.