  A theoretical study of possible signals for CPT and Lorentz violation arising
in hydrogen and antihydrogen spectroscopy is described. The analysis uses a
CPT- and Lorentz-violating extension of quantum electrodynamics, obtained from
a general Lorentz-violating extension of the minimal standard model with both
CPT-even and CPT-odd terms. Certain 1S-2S transitions and hyperfine Zeeman
lines exhibit effects at leading order in small CPT-violating couplings.
