Neuropsychological and Behavioral Effects of Antiepilepsy Drugs David W. Loring & Susan Marino & Kimford J. Meador Received: 31 July 2007 / Accepted: 27 September 2007 / Published online: 18 October 2007 # Springer Science + Business Media, LLC 2007 Abstract Antiepilepsy drugs work by decreasing neuronal irritability, which may also result in the non-desired side effect of decreased neuropsychological function. In addition to cognitive side effects, antiepilepsy drugs (AEDs) may be associated with behavioral effects which may range from irritability and hyperactivity to positive psychotropic effects on mood. There have been many new medications released since the 1990s, and although they tend to have more fa- vorable side effect profiles compared to their older counter- parts, there continues to be a risk of decreased cognitive function with the majority of these agents. The effects of in utero antiepilepsy drug exposure are increasingly being investigated, and differential drug risk is beginning to be described for both anatomic and cognitive outcomes. Pa- tients with epilepsy undergoing neuropsychological eval- uations are commonly on AEDs, and it is important for the clinician to recognize the potential contribution of AED therapy to neuropsychological profiles. The present article serves to provide an overview of our current understanding regarding the risks of antiepilepsy drug use for both cog- nitive and behavioral side effects. Keywords Antiepilepsy drugs . Neuropsychological . Cognitive and behavioral side effects Patients with epilepsy often have cognitive or behavioral dif- ficulties, which may include mild attention and concentration problems, difficulty in recent memory and learning, executive dysfunction, and social intelligence, as well as non-cognitive features of hyperactivity, irritability, and mood disturbance. Many factors potentially contribute to neuropsychological and cognitive performance in epilepsy patients including etiology and underlying brain substrate giving rise to a patient’ s epi- lepsy, seizure type and seizure syndrome, the age of seizure onset, and age at the time of the precipitating injury, as well as seizure-specific influences including seizure frequency, inten- sity, and duration (Lennox 1942; Meador 2005). Although neuropsychological function is multifactorial and will reflect multiple contributions, understanding the effects of antiepilepsy drugs (AEDs) on cognitive and behavior has special significance since the selection of AEDs can often be modified not only according to traditional measures of treat- ment effectiveness such as efficacy and tolerability, but also with respect to negative neuropsychological side effects. Be- cause many AEDs have positive psychotropic benefits, these effects may affect initial treatment choice, or subsequently modify AED treatment selection. After choosing the medica- tion based upon seizure type or epilepsy syndrome in order to maximize treatment efficacy, the cognitive and behavioral risk/benefit ratio is a primary factor to consider when for- mulating treatment plans. The presence of cognitive side Neuropsychol Rev (2007) 17:413–425 DOI 10.1007/s11065-007-9043-9 D. W. Loring : K. J. Meador Department of Neurology, University of Florida, Gainesville, USA D. W. Loring Department of Clinical and Health Psychology, University of Florida, Gainesville, USA S. Marino Department of Pharmacy Practice, University of Florida, Gainesville, USA D. W. Loring (*) McKnight Brain Institute, University of Florida, P.O. Box 100236, Gainesville, FL 32610-0236, USA e-mail: david.loring@neurology.ufl.edu