In her youth as a Frontier Brain, she acts like a princess. She was quite impatient and had an explosive temper that would erupt if she ever lost a battle. This was an even bigger problem since she possessed some sort of psychic powers that would cause serious damage.
In Pokémon Black and White, Caitlin traveled to the Unova region alone in order to develop her skills further. As seen by her facial expression, she has developed a more calmer personality to keep her temper, and thus her powers, in check.