The effects could be customisable with example options being: The name of the adverse effect, what attribute it affects (Health, Stamina, Mana, Dexterity, Luck, Movement etc), the rate at which it is affected (positive and negative values along with an option to reduce it to zero), bitmap in status screen, actions enabled or disabled, colour overlay (an RGB value which is placed over the creature bitmap or player viewport to differentiate between effects), the duration of the effect and the required spell to cure the effect.
An example would be a 'Freeze' attribute which reduces the movement rate to 0, disabling all actions, with a light blue overlay, for an indefinate amount of time.
Im not quite sure how the current poison mechanics actually work, so maybe this could not be implemented easily. However, you don't know if you don't ask

Oh and nice work of late on V0.35 GG!