Future wireless communication systems will most likely be operated at carrier frequencies above 300 GHz, where the indoor radio channel behaves entirely differently compared to legacy radio communication frequencies. Being highly relevant for system performance evaluations and channel modeling, the spatial as well as the temporal dispersions are studied for a representative office wireless LAN scenario in this paper. Ray tracing serves as the means for the accurate simulation of the THz radio wave propagation. Simple stochastic models are derived to approximate and reproduce the distance-dependent behavior of the angular spread as well as of the RMS delay spread. Based on the results, the maximum symbol rates achievable without any intersymbol interference are quantified and can be shown to reach up to several 100 GSymbols/s provided that highly directive antennas are used.