  Effective Lagrangian models of charmonium have recently been used to estimate
dissociation cross sections with light hadrons. Detailed study of the symmetry
properties reveals possible shortcomings relative to chiral symmetry. We
therefore propose a new Lagrangian and point out distinguishing features
amongst the different approaches. Moreover, we test the models against Adler's
theorem, which requires, in the appropriate limit, the decoupling of pions from
the theory for the normal parity sector. Using the newly proposed Lagrangian,
which exhibits SU_L(N_f) x SU_R(N_f) symmetry and complies with Adler's
theorem, we find dissociation cross sections with pions that are reduced in an
energy dependent way, with respect to cases where the theorem is not fulfilled.
