Throngs of screaming teenaged girls lined-up at a Chapters store in Ottawa today, to meet Justin Bieber’s mom.

Pattie Mallette is in Ottawa signing copies of her book "Nowhere But Up".

Bieber is also in town for a concert tonight at the Canadian Tire Centre.

In her book, Mallette reveals her struggles as a single mom, and how she overcame childhood sexual abuse, depression and a battle with addiction.

Mallette says, “These girls are coming up to me and showing me their scars and saying, I stopped cutting because of you, and girls who are crying and saying you saved my life I was suicidal and I'm not anymore you gave me so much hope.”

In the past few months Bieber has faced a barrage of media criticism over some antics like driving too fast in his neighbourhood, and loud parties at his home.

Bieber's grandparents say, he's just being a teenager.

"It's totally crazy,” says Diane Dale, Bieber’s grandmother. “I feel sorry for Justin all the time because paparazzi pick on him all the time. Anybody else's kids have done the same thing but nobody says anything.”

 "He's just a 19 year old boy,” says Bieber’s grandfather Bruce Dale, “and before you criticize him, say, what is my 19-year-old boy doing?”

CTV’s Natalie Pierosara will have more on this story tonight at six.