  Many stars are in binaries or higher-order multiple stellar systems. Although
in recent years a large number of binaries have been proven to host exoplanets,
how planet formation proceeds in multiple stellar systems has not been studied
much yet from the theoretical standpoint. In this paper we focus on the
evolution of the dust grains in planet-forming discs in binaries. We take into
account the dynamics of gas and dust in discs around each component of a binary
system under the hypothesis that the evolution of the circumprimary and the
circumsecondary discs is independent. It is known from previous studies that
the secular evolution of the gas in binary discs is hastened due to the tidal
interactions with their hosting stars. Here we prove that binarity affects dust
dynamics too, possibly in a more dramatic way than the gas. In particular, the
presence of a stellar companion significantly reduces the amount of solids
retained in binary discs because of a faster, more efficient radial drift,
ultimately shortening their lifetime. We prove that how rapidly discs disperse
depends both on the binary separation, with discs in wider binaries living
longer, and on the disc viscosity. Although the less-viscous discs lose high
amounts of solids in the earliest stages of their evolution, they are
dissipated slowly, while those with higher viscosities show an opposite
behaviour. The faster radial migration of dust in binary discs has a striking
impact on planet formation, which seems to be inhibited in this hostile
environment, unless other disc substructures halt radial drift further in. We
conclude that if planetesimal formation were viable in binary discs, this
process would take place on very short time scales.
