  The CPT theorem originally proven by L\"uders and Pauli ensures the equality
of masses, lifetimes, magnetic moments and cross sections of any particle and
its antiparticle. We show that in a Lorentz invariant quantum field theory
described by its Lagrangian, CPT-violating interaction alone does not split the
masses of an elementary particle and its antiparticle but breaks only the
equality of lifetimes, magnetic moments and cross sections. However, CPT
violation in the mass term of a field in the Lagrangian, which can be
attributed to be due to the size of the particle described by a form factor,
breaks only the equality of masses. Also it is shown that the two separate
effects of CPT violation in the interaction terms or in the mass term do not
mix due to higher quantum corrections and remain distinguishable. Thus, we urge
the experimentalists to search for such observable effects concerning
differences in the masses, magnetic moments, lifetimes and cross sections
between the elementary or bound state particles and their antiparticles. In the
case of CPT violation only in the mass term, besides the difference in the
masses of elementary bound state particles and their antiparticles, there will
be also an extremely tiny difference in the lifetimes of bound states due to
the difference in their phase spaces. From the details of calculations, it
appears that the separate effects of the CPT violation described above are
quite general, neither depending on how the nonlocality is achieved, nor
depending on what this violation is due to: due to T violation, as considered
in the present work, which can be attributed to a cosmological direction of
time; to CP or to both T and CP violations. The latter two cases satisfy the
Sakharov's conditions for explaining the baryon asymmetry in the Universe.
