Teenagers have a "cauldron" of hormones and emotions bubbling inside them that require delicate handling, a grief counsellor says.
An Education Ministry trauma team has been at King's College since the death of Michael Treffers - the third student to die in as many months.
Youthline national spokesman Stephen Bell
said it was vital parents let their children know they were always there if they needed them.
Chris Caruana, a former counsellor at Mt Roskill Grammar, said: "The risk is always heightened if someone's friend has recently died or there are alcohol or drugs involved."
He said parents and teachers needed to look out for "telltale signs" such as sudden changes in behaviour, a sense of apathy and a lack of purpose among students.
"Grief has a way of distorting our perception of things. If they say things like, 'I wish I wasn't here, I don't know why I'm living,' questioning the meaning of life.
"If I was suspicious of someone harming themselves I would be quite overt about it. I don't think there is any point in shying away from the subject.
"We can make rash and regrettable decisions."
