"Madness and Civilization was also famously criticised by Jacques Derrida who took issue with Foucault's reading of René Descartes' Meditations on First Philosophy. Derrida's criticism led to a break in their friendship and marked the beginning of a fifteen-year–long feud between the two. (At one point, in a 1983 interview with Paul Rabinow, Foucault seemed to criticize Derrida's reading of Plato's Phaedrus in Of Grammatology, considering the writing/speech distinction unimportant.) They eventually reconciled in the early 1980s (reportedly, this reconciliation was due in part to Foucault's defense of Derrida after the latter was alleged to have been caught with marijuana in Prague)."
Derrida and marijuana? Things are suddenly becoming much clearer. What's next? Deleuze and acid?
Of course we know that Derrida was indicted by the communists for speaking up against them during a conference. Still you can't but wonder.