in australia, they are meant to let someone know if you are planning on hurting yourself, or someone else, or know of someone under 18 being hurt.

otherwise, if it doesn't involve physical harm to other people, the general rule is that they won't tell unless it's something that can get you sent to prison for 5 years. so my T used to tell me that if i ever wanted to speak about something like that, to make it sound like it was something that wouldn't get me imprisoned for more than 5yrs.