By all accounts from practicing Buddhists, Kerouac's knowledge of and practical use of Buddhism was superficial at best, manufactured at worst. While it seemed as though he had a technical grasp of the idioms encompassing an intellectual approach to buddhism, like most catholic conservatives (i being one of them)it is a near impossible task discard all vestiges of one's acquired messiah complex.
But, no , i don't regard the whole Buddhist/Catholicism question as being the root of his psychological problems (if that is question you are posing). The turmoil is merely symptomatic of man who most obviously was sentimentally attached to the rituals and beliefs of his family and yet attracted to that which would differentiate him from the Lowell rabble. If nothing else, Keroauc demonstrates in Desolation Angels that he is constantly internally polarized about the universe and his place in it.
Alcoholism? Genes? I'm curious to hear what others think.