  Quantized chaotic systems are generically characterized by two energy scales:
the mean level spacing $\Delta$, and the bandwidth $\Delta_b\propto\hbar$. This
implies that with respect to driving such systems have an adiabatic, a
perturbative, and a non-perturbative regimes. A "strong" quantal
non-perturbative response effect is found for {\em disordered} systems that are
described by random matrix theory models. Is there a similar effect for
quantized {\em chaotic} systems? Theoretical arguments cannot exclude the
existence of a "weak" non-perturbative response effect, but our numerics
demonstrate an unexpected degree of semiclassical correspondence.
