[Severe vigilance disturbances: a rare complication of sodium valproate treatment (author's transl)].

Severe vigilance disturbances are rarely observed during sodium valproate treatment. Two such cases are reported, with rapid appearance of mental confusion after starting treatment, associated with an overall slowing of the E.E.G. the plasma levels of the different anti-epileptic agents were normal or only slightly raised and could not have caused the phenomenon. Clinical and electrical signs regressed as rapidly after stopping valproate administration as they had appeared after starting treatment.