Complex sentence: Following a period of depression, during which she became locked up in her home, she decided to abandon her career, but, at the same time, she was writing the material that would make her famous as a solo artist.
Split into simpler sentences: Following a period of depression, during which she became locked up in her home, she decided to abandon her career. But, at the same time, she was writing the material that would make her famous as a solo artist.