The major symptoms of ODD are defiance, extreme stubbornness, temper and anger problems, and being argumentative. Boys are diagnosed with ODD more often than girls before puberty. After puberty, this number becomes more even between girls and boys.
Although some experts believe that ODD may lead to Conduct Disorder, other experts disagree and believe these to be two separate mental illnesses.
For more information:
How Are ADHD and OOD Different?