She has since adopted a healthy new lifestyle and slimmed down, losing 48 pounds (21.7 kilograms) during a recent stint on TV talent show Dancing With The Stars.
Osbourne admits she was often bullied for her fuller figure, and she's convinced hurtful jibes about her size contributed to her drug problems.
She tells Shape magazine, "I understand that being judged by others comes with the territory, but it broke my heart and ruined my self esteem. It sets you up to hate yourself in a huge way. I was so angry about the things people said about me. I truly believe it's the main reason I turned to Vicodin and ended up in rehab three times. I just hated myself."