  In this letter, we investigate the performance of reconfigurable intelligent
surface (RIS)-assisted communications, under the assumption of generalized
Gaussian noise (GGN), over Rayleigh fading channels. Specifically, we consider
an RIS, equipped with $N$ reflecting elements, and derive a novel closed-form
expression for the symbol error rate (SER) of arbitrary modulation schemes. The
usefulness of the derived new expression is that it can be used to capture the
SER performance in the presence of special additive noise distributions such as
Gamma, Laplacian, and Gaussian noise. These special cases are also considered
and their associated asymptotic SER expressions are derived, and then employed
to quantify the achievable diversity order of the system. The theoretical
framework is corroborated by numerical results, which reveal that the shaping
parameter of the GGN ($\alpha$) has a negligible effect on the diversity order
of RIS-assisted systems, particularly for large $\alpha$ values. Accordingly,
the maximum achievable diversity order is determined by $N$.
