Thank you to the person who is actually doing the research. Maybe reading the actual paper once it is peer-reviewed and published, will help.

I believe OP is not the researcher?

The moot point being whether all the points that OP highlighted are actual causalities that have led Nepali diaspora to a point where mental illness is now 'endemic'?
I beg to differ. How will the researcher measure prevalence of mental illness? Are those variables that OP mentioned, measurable? How are those variables any different than what any Filipino, Vietnamese, Djiboutian face in US? Will those same measures apply to folks who are in Nepal or in Liberia? Is "Life in the modern world" a cause for mental illness? Is this steering towards philosophy now?

Eagerly waiting for the paper to be published. Best wishes.