According to a survey, which was carried out to mark Mental Health Action Week, in Scotland, more than 80 percent of respondents know two friends who have experienced mental distress at some time or the other.
The survey also showed that almost 90 percent of those suffering from mental distresses would never think of revealing it to others, out of shame for appearing weak or because they felt their friends would not understand.
Other findings included the fact that 62 percent of people in Scotland felt that they knew enough about mental health issues to help friends who were experiencing a problem. Also a total of 44 percent of people living in Scotland said that during a period of mental ill health, friends provided the most support - much more than family members and professionals.
Another fact was that two thirds of people surveyed admitted to feeling frustrated because there was no simple solution to a friend's mental health problem.
Says Dr Andrew McCulloch, chief executive of the Mental Health Foundation: "Friendships are very important for good mental well-being, yet people can feel ashamed or embarrassed to tell their friends about how they feel, and friends are sometimes unsure of how exactly they can help.
"People who feel mentally unwell might find it hard to discuss how they're feeling but friends can provide support."
The Mental Health Foundation has come out with a new booklet called Keeping Us Going, which offers help and guidance for people with mental health problems and their friends.