  The observed anomalous excess of high-energy cosmic ray (CR) positrons is
widely discussed as possible indirect evidence for dark matter (DM). However,
any source of cosmic positrons is inevitably the source of gamma radiation. The
least model dependent test of CR anomalies interpretation via DM particles
decays (or annihilation) is connected with gamma-ray background due to gamma
overproduction in such processes. In this work, we impose an observational
constraint on gamma ray production from DM. Then, we study the possible
suppression of gamma yield in the DM decays into identical final fermions. Such
DM particles arise in the multi-component dark atom model. The influence of the
interaction vertices on the gamma suppression was also considered. No essential
gamma suppression effects are found. However, some minor ones are revealed.
