“We are deeply shocked,” said Günter Hagedorn, president of Biermann’s club FSV Spandauer Kickers 1975.
Biermann spoke out about his illness in 2009 following the suicide of goalkeeper Robert Enke who played for the national side.
Torsten Mattuschka, who played with Biermann at FC Union, said: “He had already tried it a few times. You thought that he had it under control. Unfortunately, he didn't.”
The FC Union captain added: “It’s a tragedy. How desperate do you have to be as a father-of-two to do that?”
The club’s president, Dirk Zingler, wrote on the FC Union homepage: “He fought long and courageously against his illness but he couldn’t win the fight. We are shocked and saddened.”
In 2009, the former defender revealed he had tried to take his life in October of that year. Biermann published a book called "Depression: Red Card" where he discussed his struggle.
He had taken therapy and said in 2009 he hoped to get rid of the taboo surrounding the illness by speaking about it.