Trader had family problems

According to the AP:

Managers who briefed Union officials on Thursday told them that the trader was having "family problems." The union official said the trader "might have lost his mind a bit"

One of his former teachers, Gisele Reynaud, described Kerviel as a "brilliant" student. She taught him at a university in Lyon, where he graduated in 2000 after an intensive year-long course in how to track, monitor and keep account of the type of trades that he went on to do at Societe Generale. She said the course was very technical and intense, and included accounting, information technology and law. "He was a nice guy," Reynaud said. "He was brilliant".