What must be immediately reported to the elders in the Community in The Giver so that people might be medicated to prevent it?

When adolescents begin to experience sexual desire, they are given pills to suppress these feelings, which are referred to as Stirrings. Jonas has a dream about Fiona in which he wants her to take off her clothes so that he can touch her and bathe her in a bathtub. Jonas reports this to his parents and is given the same pills that adults in the community take.
When he becomes Receiver of Memory, Jonas is exempt from taking these pills. As the Giver shares memories with him, Jonas learns that true emotions cannot be experienced by the community without them. Emotions are suppressed within the community with pills and also by the ideologies of the community itself—there are no words to describe emotions.