In many types of epilepsy, both idiopathic and symptomatic, seizures are more likely to occur at times of stress, menstruation, sleep deprivation, fever, metabolic disturbance, hypoglycemia, and so on. These are commonly known as seizure precipitants and are widely accepted. Seizures that are due to reversible environmental triggers such as metabolic change or fever have no known physiological difference from those of patients with epilepsy who experience seizures provoked by the same cause. Most of the scientific work has focused for obvious reasons, on the seizures in reflex epilepsies, as these seizures can be reliably provoked and therefore studied in laboratory conditions and also because there are a number of suitable animal models. The remarkable suppression of photosensitivity by valproate or levetiracetam and the absence of any effect by carbamazepine is an example. Similarly, GABAergic drugs seem particularly effective in the photosensitive baboon Papio papio and the audiogenic mouse models.