  We extend the perturbative approach developed in an earlier work to deal with
Lagrangians which have arbitrary higher order time derivative terms for both
bosons and fermions. This approach enables us to find an effective Lagrangian
with only first time derivatives order by order in the coupling constant. As in
the pure bosonic case, to the first order, the quantized Hamiltonian is bounded
from below whenever the potential is. We show in the example of a single
complex fermion that higher derivative interactions result in an effective mass
and change of vacuum for the low energy modes. The supersymmetric
noncommutative Wess-Zumino model is considered as another example. We also
comment on the higher derivative terms in Witten's string field theory and the
effectiveness of level truncation.
