Yes, there are many things. The most important fact that drove her to insanity was the dwindling affection that her father exhibited towards her. As a child, Ozai showed favoritism towards Azula, which Azula mistook for love. She used her father's acceptance as a way to somehow fill in the void that her mother never filled. Ozai left Azula in the Fire Nation, a symbol of the fact that he no longer valued her. She exhibited great distress upon being deserted by her father, feeling as if he was treating her like Zuko. Another factor that contributed to Azula's mental instability was the betrayal of Mai and Ty Lee. She considered them as her only true friends, although fully aware that they only follow her due to intimidation and fear. When time came, however, Mai chose Zuko, and Ty Lee sided with Mai, again rekindling Azula's sibling rivalry with her brother. The thought of an emotion such as love, which she has never truly experienced, being more powerful than the fear she invoked, drove her insane.
Long term ego-maniacal issues aside, Azula's mental instability was most directly triggered when she was betrayed by Mai and Ty Lee. Her self-identity was based on the idea that she had superior powers of manipulation and intimidation. When Mai defied her and Ty Lee attacked her, her illusions were shattered and her reality and mental stability began crumbling. She began banishing everyone around her from the Fire Nation in fear that they would also betray her and could not be controlled by fear as she wanted. By the time she was forced to confront Zuko, who was the one her mother favored from the beginning and therefore the root of all her insecurities, she simply snapped and abandoned her previous values of perfection and self-control, which is evident during her Agni Kai with Zuko when she becomes "out of breath" for the first time, leading her to attack Katara in hopes of distracting her now dominant opponent, Zuko.