Crown Princess Masako, who continues to limit her official duties due to a stress-induced illness, celebrated her 46th birthday Wednesday and vowed to continue her efforts to recover from the illness. The wife of Crown Prince Naruhito, the eldest son of Emperor Akihito and Empress Michiko, has refrained from most of her official duties since the agency announced in December 2003 that she is suffering from a stress-related disorder. She was diagnosed with an adjustment disorder in July 2004.