More than a quarter of young people would turn to the internet first if they were upset or had a problem, according to a new survey.
Children as young as 13 would seek out online help, ranging from searching for information to looking at websites specifically designed for young people.
More than one in three (34%) would talk to a parent or carer first, while 27% would speak to another person they trusted and 28% would turn to the internet first.
Meanwhile, 36% would tell friends to avoid Facebook if they were feeling worried or upset.
Of those surveyed, 75% said the internet makes them happy. But when asked if it was bad for young people's mental health, 28% agreed it was.
The poll, for family online safety experts Parent Zone, also found that more than half (51%) of 13 to 20-year-olds have read or seen someone discussing suicide online.
Six out of 10 (61%) have also seen someone talk about hurting themselves on the internet.
The poll of 220 students aged between 13 and 20 was accompanied by in-depth interviews with an extra 40 children.
A total of 119 teachers were also polled, while a further six teachers were interviewed in-depth.
Of the teachers, 44% said the internet is bad for young people's mental health and 91% believe the frequency of mental health issues among pupils is increasing.
Stress and anxiety, depression and self-harm were the most common issues seen in schools.
Most teachers said they did not have adequate resources to deal with pupils' mental health issues.
Vicki Shotbolt, chief executive of Parent Zone, said: "Family life is arguably more complex now than it has ever been.
"Children have access to information, views and opinions that adults cannot control. The internet has destroyed any notions we might have had about keeping some things away from children until they were 'old enough to cope'.
"All of the indicators suggest that the prevalence of mental health problems and the severity of those problems are increasing.
"Some people are linking the internet to the increase so we wanted to speak to the young people who have grown up with technology and hear their views so that we can start to think about how best to support them."
Parent Zone and Ceop Command (formerly the Child Exploitation and Online Protection Centre) - part of the National Crime Agency - publish Parent Info, which offers information to help children and young people stay safe online for schools to host on their own websites.
A spokesman for the NSPCC said: "Socialising online is central to children and young people's lives today, but this report exposes some of the anxieties - which we know all too well from calls to ChildLine - that they experience from using the internet and the impact it can have on their mental health.
"The industry has a responsibility to keep young people safe when they use their services and, whilst some progress has been made, there is much more to do.
"When children and parents report online hate messages, companies must take swift action to prevent further distress to victims. We must do more to protect young people online."