Struensee wrote an important report on the mental health of the King First he reconciled the king and queen.
He supported these new ideas, becoming a proponent of atheism, the writings of Claude Adrien Helvétius, and other French materialists.When Adam and Maria Dorothea Struensee moved to Altona in 1758, where the elder Struensee became pastor of Trinitatiskirche (Trinity’s Church), Johann Friedrich moved with them.When in the course of the year the king sank into a condition of mental torpor, Struensee's authority became paramount.At first, Struensee kept a low profile as he began to control the political machine.The royal court and government spent the summer of 1770 in Schleswig-Holstein (Gottorp, Traventhal and Ascheberg).
On 15 September the King dismissed Chancellor Bernstorff and on 18 December Struensee appointed himself maître des requêtes (privy counsellor), consolidating his power and starting the 16-month period generally referred to as the "Time of Struensee".
However, in December he grew impatient, and on the 10th of that month he abolished the council of state.
A week later he appointed himself maître des requêtes.
He also took Rousseau's advice about cold being beneficial for children literally, and the Crown Prince was thus only sparsely clothed even during winter time.
Struensee was named royal adviser (forelæser) and konferensråd on .
Rantzau recommended Struensee to the court as a physician to attend King Christian VII on his forthcoming tour to princely and royal courts in western Germany, the Netherlands, England, and France. During the eight-month tour he gained the king's confidence and affection.