YMCA has been speaking after it polled 2,000 11-24 year olds and found 38 per cent had been shunned because of their mental health problems.
A third of that group said they were alienated every week.
More than half of the stigmatisation comes from a person's own friends, according to the poll, and examples include verbal abuse and being left out of activities.
YMCA, NHS + Jordan Stephens from @rizzlekicks launch #IAMWHOLE mental health campaign today! Together we are whole. https://t.co/2WiAoSIWli
— YMCA England (@YMCA_England) 10 October 2016
This made them 56 per cent less likely to seek help from a medical professional - making them less likely to get better - and 70 per cent less likely to speak about their problems generally.
The study revealed young people were significantly affected by stigmatisation, with 85 per cent reporting lower confidence and nearly three in five (59 per cent) reporting that their schoolwork suffered.
YMCA has launced the #IAMWHOLE campaign in an attempt to get people talking about mental health issues.
Liam Preston, from YMCA, told Premier: "If they're not willing to talk out about it and they're not willing to get help, their mental health difficulties will only get worse.
"When you see harmful language being used, it's about challenging that to say: 'that's not right, and we need to have a better understanding about how people feel'."
Liam encouraged listeners to pray, saying: "It's about asking to give those who're suffering and aren't willing to speak out, giving them the strength to go out and seek help, and also for people to reflect on the language that they use and see how they can change that for the better."
Listen to Premier's Hannah Tooley speaking to Liam Preston:
