Antiepileptic drugs (AEDs) have been widely used by psychiatrists to treat disorders other than epilepsy for two decades. Here I survey those uses and selectively review the side effects of AEDs in the psychiatric context.

AEDs are now so widely used for non-epileptic indications that the appellation “anti-epileptic drug” may verge on mislabelling (to paraphrase David Healy’s comment about serotonin-reuptake inhibitors and “antidepressants”). Nonetheless, no better designation is available, and I refer to these drugs as AEDs. Oddly, the newer AEDs may prove be more useful in psychiatric illness than in epilepsy, where their greater efficacy than the older agents has not yet been conclusively demonstrated.¹

An assumption that the mechanisms of action of AEDs are the same in epilepsy and in psychiatric disorders would go beyond the evidence. Activity against kindling has been proposed to explain the psychotropic effect,² but this seems to account for neither the spectrum of psychiatric benefits nor the range of beneficial drugs. A division of psychotropic effects into “sedating” (mediated by GABAergic action) and “activating” (mediated by antiglutamatergic action)³ likewise may fail to capture the diversity of psychotropic “principles” by which the diverse category of AEDs exerts psychotropic effects.⁴

Although I review scientific data regarding the use of AEDs in psychiatry, a non-scientific factor, of uncertain power, may partly account for the rise in prescription of AEDs. The interest of pharmaceutical firms in expanding the use of their products and their willingness, at least in some instances, to use improper means have recently been highlighted by the guilty plea of a major company in a case involving marketing an AED for off-label indications.⁵ Since the scientific evidence in the realm reviewed is far from complete, …