In the Śrīmad-Bhāgavatam, Seventh Canto, 4th Chapter, 30th verse, Prahlāda Mahārāj says that even in his childhood, when he was loudly speaking the glories of the Lord, he used to dance just like a shameless madman. And sometimes, being fully absorbed in thought on the pastimes of the Lord, he used to imitate such pastimes. This is an instance of a devotee's being almost like a madman. Similarly, it is said that the great sage Nārada was so ecstatically in love with Kṛṣṇa that he would sometimes dance naked, and sometimes his whole body would become stunned. Sometimes he would laugh very loudly, sometimes he would cry very loudly, sometimes he would remain silent, and sometimes he would appear to be suffering from some disease, although he had no disease. This is another instance of becoming like a madman in the ecstasy of devotion.

Chapter 38: Indifference and Separation