Quantization in the minisuperspace of non-minimal scalar-tensor theories le
ads to a partial differential equation which is non separable. Through a co
nformal transformation we can recast the Wheeler-DeWitt equation in an inte
grable form, which corresponds to the minimal coupling case, whose general
solution is known. Performing the inverse conformal transformation in the s
olution thus found, we can construct the corresponding solution in the orig
inal frame. This procedure can also be employed with the Bohmian trajectori
es. In this way, we can study the classical limit of some particular soluti
ons of this quantum model. While the classical limit of these solutions occ
urs for small scale factors in the Einstein frame, it happens for small val
ues of the scalar field non-minimally coupled to gravity in the Jordan fram
e, which includes large scale factors.