At first glance, the members of Clan Malkavian do not
  appear to be a clan at all; they are chosen from all races,
  creeds and social strata. But Malkavians, regardless of
  mortal standing, bear one disturbing commonality: They are
  all quite mad. Whether from the clan's choice of victims, the
  circumstances of the Embrace, or some property in
  Malkavian blood itself, all Malkavians go insane shortly after
  the transformation (if they were not insane to begin with).
        Accordingly, many Malkavians find themselves
  pariahs, ostracized by a vampiric society fearful of their
  random urges and capricious whims. Wiser Kindred,
  however, prefer to keep the madmen close at hand: Behind
  the Malkavians' lunatic cackling and feverish rantings lie
  smatterings of insight, even wisdom.