3. Mischa Barton
Mischa Barton achieved success early in her career following her stint as Marissa Cooper in The O.C. Regrettably, film offers started decreasing drastically after The O.C, and the actress started displaying dramatically fluctuating weight losses and gains. She also ran into trouble with the law enforcers in 2007 for DUI and possession of drugs. Currently, her hectic and unhealthy lifestyle have enforced accelerated aging and we are devastated!