Just 37% of 15-25-year-olds would tell someone if they were struggling.
A new campaign aims to tackle the stigma that stops young people speaking about their mental health.
See Me found just 37% of people aged 15-25 would tell someone if they were finding it difficult to cope with their mental health, compared to 78% who would tell someone if they were physically ill.
Young people also believed they were not taken seriously by adults when they voiced concerns over their mental health, a poll for the charity found.
When asked how they cope with negative thoughts and feelings only 21% said they would speak to someone who supports them. Almost half – 46% - said they would rather stay by themselves and 50% would cope by crying.
However, in a separate survey of Scottish adults with a young person in their care, 83% said they would feel confident talking to a young person about mental health and 76% said they would be confident knowing where to go for help and advice.
See Me’s new campaign, It’s Okay, aims to bridge this gap and encourage young people to seek help before they reach breaking point.
Lisa Cohen, See Me programme manager, said: “Young people don’t feel that adults take them seriously when it comes to mental health. But they should be able to speak openly about what they are going through, without feeling guilty. It is okay not to be okay.
“Everyone involved in young people’s lives needs to have the confidence to open up conversations about mental health and be supportive about what to do next.
“We all need someone we can talk to and trust. We want young people to know that there will be a person that will have the ability to listen and be there for you. ”
The campaign will see the launch of a website and video aimed at breaking down discrimination around mental health while schools will be given resources to help teachers explain the issue to their classes.
Emma Hewitt, 20, from Paisley, first experienced difficulties with her mental health when she was 13, with issues of self-harm and suicidal thoughts.
She said: “If there was more information around I would have known what to look out for and would have maybe gone and spoken to someone before I was forced to.
“If you have a physical problem you go and tell your parent or the school nurse. But if you have a mental health problem it isn’t that easy. At 12 or 13, I didn’t talk about mental health, I didn’t know anything about it.
“Adults didn’t really tend to understand or know what to do, so I thought it was better to keep it to myself. It would have been easier if someone had spoken to me.”