Very prevalent in the industry I am afraid, especially in the bigger airlines where individuals spend long periods away from home, friends, family with a group of strangers week in and week out. It is not a job for people with baggage back home.
There has certainly been an increase in BA in recent years with a few very sad stories from both sides of the flight deck door. We have a counselling department in operation which can be contacted 24 hours a day anywhere in the world but sadly it is up to the individual to realise they need it before its too late!