Lunardi M, et al. - Researchers conducted the study for analyzing the significance of “subtherapeutic” vs “therapeutic” antiepileptic drug (AED) plasma levels with respect to treatment adherence. Study participants included 170 patients with refractory temporal lobe epilepsy who had video-EEG monitoring in view of a surgical indication had their AEDs (carbamazepine, phenobarbital, phenytoin, and valproate) rapidly withdrawn following a standardized schedule. They observed that adherence was found in 73.2% of cases and nonadherence in 26.8%. "Subtherapeutic" AED plasma levels are rarely caused by nonadherence, whereas "therapeutic range" levels do not show that the patient adheres to treatment. Any level needs to be compared with other levels of the same patient for meaningful interpretation. The principle of individualized therapeutic AED monitoring as promoted by the Therapeutic Strategies Commission of the ILAE was strongly emphasized.