  An investigation of two-time correlation functions is reported within the
framework of (i) Stochastic Quantum Mechanics and (ii) conventional
Heisenberg-Schr\"odinger Quantum Mechanics. The spectral functions associated
with the two-time electric dipole correlation functions are worked out in
detail for the case of the hydrogen atom. While the single time averages are
identical for stochastic and conventional quantum mechanics, differences arise
in the two approaches for multiple time correlation functions.
