"There is nothing wrong with him. He is in a great place. Justin is good, really good," Bieber's manager Scooter Braun told eonline.com.
It has been claimed Bieber's meltdown is because of his split from Selena Gomez in January after about two years of relationship.
"He simply hasn't been the same since he split from Selena. It really broke him. They were together for such a long time for two people so young. He hasn't quite known what to do without her," said a source.
"He is lonely. They kept each other very grounded and understood the level of fame that they both had. Now his friends know he needs their support more than ever," added the source.
Bieber's grandmother Kathy Bieber has defended him against accusations he has turned into a bad boy, but insists he should put on a free concert for his fans in Britain.