9. Britney Spears
After being part of the squeaky clean neon nightmare that was The Mickey Mouse Club, Britney became the most famous female face in the world in 1998 after releasing her debut single "Baby One More Time", aged just 16. What followed was a prime example of a child star meltdown in adult life. In 2007 she had what has been described as an inevitable breakdown in front of the mass of paparazzi who followed her around for her entire career; was charged with a hit-and-run; spent some time beating a photographer's car with an umbrella; and lost custody of her kids to her ex-husband Kevin Federline. Not wanting to be considered unfashionable, she had a number of obligatory celebrity stints in rehab, but the icing on the cake was her decision to embrace the chromedome by shaving her head bald in the craziest celebrity breakdown stunt of recent years.