Lady Gaga was "humiliated, taunted, and isolated" during her school years.
The 'Shallow' hitmaker - whose real name is Stefani Germanotta - went through "a lot of difficult times" whilst she was in school, according to her mother Cynthia Germanotta, who has said she found it hard to watch her daughter go from being "very happy and aspirational" to "questioning to her self-worth".
Cynthia said: "Stefani was very unique and that wasn't always appreciated by her peers and, as a result, she went through a lot of difficult times. Humiliated, taunted, isolated. When you're a young woman, this really severely impacts you.
"It was in middle school when I saw that turn happen - when she went from a very happy and aspirational young girl to somebody that started to question her self-worth, to have doubts about herself and that is when we actually saw the turn."
And although she wanted to help her daughter, Cynthia says she "wasn't prepared" to talk to the 'Bad Romance' singer, 44, about her mental health.
She added: "I believe that we, as both individuals and society, we don't treat [mental health] the same way that we treat physical health. So, certainly when it happened in our house, I didn't know what to look for. As a parent, I wasn't prepared to really address this.
"When I was growing up, times were different. The way that we would deal with things is what I learned, and that's what I resorted to ... I relied on getting a grip. I relied on the generational grit of just sucking it up and getting on with it."
Cynthia has since helped her daughter co-found the Born This Way Foundation, and now has a better understanding of mental health issues and the ways they impact people across the globe.
She said: "What I didn't realise is the profound impact that it can have. It basically turns the focus of everything onto that one individual and families feel conflicted about it, they don't really understand it, it causes conflict and a lot of stress within the families. It can also cause feelings, for me personally, feelings of guilt, of helplessness - not knowing how to help my daughter. So, what I really learned is that no family is immune from this and we should all really learn where we would go and who we would turn to if something like this happened in our families."
Now, Cynthia is urging other parents to "listen and understand" the problems their children are facing.
Speaking on 'CBS This Morning', she said: "The most important thing that [parents] can do is really listen and understand. What I learned from my daughter is to listen and validate her feelings. I think as parents, our natural instinct is to go into problem-solving mode ... when, in fact, they really just want us to take them seriously and understand what they're saying.
"I encourage parents to be vulnerable. Talk about your current or past struggles, so it really models healthy conversations and good behaviour. So, the biggest thing is to really talk to them and it's certainly ok to not be ok and start to have these conversations."