CC Ādi 17.7
bhakta-gaṇa lañā kaila vividha vilāsa
In His youth the Lord exhibited His ecstatic love of Kṛṣṇa on the plea of disturbances of the bodily airs. Accompanied by His confidential devotees, He enjoyed various pastimes in this way.
According to Āyur-vedic treatment, the entire physiological system is conducted by three elements, namely vāyu, pitta and kapha (air, bile and mucus). Secretions within the body transform into other secretions like blood, urine and stool, but if there are disturbances in the metabolism, the secretions turn into kapha (mucus) by the influence of the air within the body. According to the Āyur-vedic system, when the secretion of bile and formation of mucus disturb the air circulating within the body, fifty-nine varieties of diseases may occur. One such disease is craziness.
On the plea of disturbance of the bodily air and metabolism, Śrī Caitanya Mahāprabhu acted as if crazy. Thus in His school He began to explain the grammar of verbs through Kṛṣṇa consciousness. Explaining everything in grammar in relationship to Kṛṣṇa, the Lord induced His students to refrain from worldly education, for it is better to become Kṛṣṇa conscious and in this way attain the highest perfectional platform of education. On these grounds, Śrī Jīva Gosvāmī later compiled the grammar entitled Hari-nāmāmṛta-vyākaraṇa. People in general consider such explanations crazy. Therefore the Lord’s purpose in His attitude of craziness was to explain that there is nothing within our experience but Kṛṣṇa consciousness, for everything may be dovetailed with Kṛṣṇa consciousness. These pastimes of Lord Caitanya Mahāprabhu have been very vividly described in the Caitanya-bhāgavata, Madhya-līlā, chapter one.