In the Netflix series "Queen Charlotte: A Bridgerton Story," King George III struggles with his mental health. The character is based on the real King George III, who suffered from a mental disorder that caused him to have good and bad days. While the series does not provide a specific diagnosis, some medical historians have suggested that the real King George IIIs mental instability was caused by a hereditary physical disorder called porphyria. The series portrays the king's struggles with his illness and the weight of the crown, and shows how it affects his relationship with Queen Charlotte.