Newer AEDs Most of the information reviewed so far dealt with the established AEDs. Although these drugs have been available for many years and have been studied rather extensively, it is apparent that few firm conclusions can be drawn regarding any aspect of their cognitive effects. As expected, fewer studies have been carried out on the newer AEDs, especially in children, but these studies may have benefited from the lessons drawn from studies on the established drugs. Unfortunately, newer drugs have been tested mostly in add-on trials so far. For instance, cognitive testing was included in a double-blind, placebo controlled crossover study of gabapentin (GBP) efficacy at doses of up to 2,400 mg/day (61). Psychomotor and memory scores were not affected by GBP, and only the drowsiness score was higher at 2,400 mg/day. In an open study, lamotrigine (LTG) was added to CBZ in 25 adult patients (62). They were tested at baseline and after 5 months of LTG treatment. No statistically significant change was found for any of the test scores. Ten subjects receiving topiramate underwent weekly digit span tests to assess their attention over a 3-month period (63). In four subjects, attention was impaired in a dose related fashion. The effects of tiagabine (TGB) were assessed in the context of controlled studies in adults. The addition of TGB could not be shown to cause clinically important changes in terms of cognitive and quality of life effects in three studies in adults (6446). Patients who attained TGB monotherapy improved in the areas of adjustment and mood (67), a change attributable most likely to discontinuation of previous AEDs. Similarly, several investigations of the cognitive and behavioral effects of VGB have shown no or only minimal impairment, and even some evidence of improvement (68-72). Psychosis and depression have been repeatedly described with VGB, both in adults and in children (73-75).