  We analyze the "vacuum" polarization induced by a quantum charged scalar
field near the inner horizon of a charged (Reissner-Nordstr\"om-de Sitter)
black hole in quantum states that start out as regular states near an initial
Cauchy surface. Contrary to the outer (i.e. event-) horizon, where polarization
effects lead to a discharge, we find that near an inner horizon, the
transversal component of the expected current density can have either sign
depending on the black hole and field parameters. Thus, the inner horizon can
be charged or discharged. But we find that it is always discharged close to
extremality thus driving the black hole interior away from this critical point.
Furthermore, we find that quantum effects dominate in that the strength of the
blow up of the quantum current at the inner horizon is state-independent and
stronger than that of the current of a classical solution.
