Suicidal or joking?

I'm abit worried about some friends that were passing notes with stuff like: "Don't worry, sometimes I want to die, too" and "but I really want too". They both have emotional problems that should be let out. They both keep a diary, but I'm afraid that they might not be opening up for fear of someone coming across it. Gosh, I'm not trying to be mean, but i think that they should face the problem. Sometimes yourself is the only one who can solve the mystery.
With lots of love,
Bee