Together with his Beatles bandmate John Lennon and their wives, Harrison first took acid in March 1965. He likened the heightened awareness induced by the drug to "a light-bulb on in my head" and "gaining hundreds of years of experience within twelve hours". In addition, he credited LSD as being the catalyst for his interest in Indian classical music, particularly the work of Ravi Shankar, and Eastern spirituality. By the time Harrison wrote "It's All Too Much", in 1967, the Indian sitar had temporarily replaced the guitar as his main musical instrument, as he received tuition from Shankar and one of the latter's protégés, Shambhu Das. As with his other songs from this period, however, such as "Within You Without You" and "Blue Jay Way", Harrison composed the melody on a keyboard instrument. In the case of "It's All Too Much", his use of Hammond organ allowed him to replicate the drone-like sound of the harmonium commonly heard in Indian vocal pieces.