  Relativistic particles with higher spin can be described in first
quantization using actions with local supersymmetry on the worldline. First, we
present a brief review of these actions and their use in first quantization. In
a Dirac quantization scheme the field equations emerge as Dirac constraints on
the Hilbert space, and we outline how they lead to the description of higher
spin fields in terms of the more standard Fronsdal-Labastida equations. Then,
we describe how these actions can be extended so that the propagating particle
is allowed to take different values of the spin, i.e. carry a reducible
representation of the Poincar\'e group. This way one may identify a four
dimensional model that carries the same degrees of freedom of the minimal
Vasiliev's interacting higher spin field theory. Extensions to massive
particles and to propagation on (A)dS spaces are also briefly commented upon.
