The biological theory explains how the mind and body together cause people to act a certain way. Britney Spears at one point in her career was actively taking Crystal Meth. Crystal Meth has many severe affect on a user, these affects include depression, obsessive behavior, uncontrolled judgment, and aggression. Britney went into a hair saloon and shave off all of her hair to eliminate evidence of her drug usage. Also, Spears has Bipolar Disorder, which the prefrontal cortex is smaller then normal. Therefore, people who have this disorder like Britney had mood swings, trouble solving problems, and a hard time making decisions.