That "study" shall be outside this thread as decided by Senior Pilot.
If you wish to conduct such a general discussion about such issues you can feel free to do it in a new Thread so long as you do not make reference to this particular tragedy without citing an official reference from the Accident Investigation or other such official authority involved in that investigation.
Discussion of alcohol use along with the consumption of other substances in addition to or/with psychological problems are a fact of life as Helicopter Pilots are humans and thus a topic of concern.
Just take that general discussion elsewhere.