To 26 out-patient epileptics on continuous anticonvulsant medication and to their individually matched non-epileptic controls, a battery of psychological tests (intelligence, personality, etc.) was administered twice, with 3 months between tests. Performance changes by the control subjects could be attributed to retesting; any additional changes made by the epileptic group may, with caution, be attributable to the effects of medication. The major overall finding is the paucity of such changes in the epileptic group. Only 44 out of 2000 tests for changes yielded statistically significant results and the significance of these few is open to question. Even if all 44 of these changes should prove, on further testing, to be significantly and causally related to medication, continuous use of these drugs would not be contraindicated, since the changes were as often as not in a healthier direction. Clinical ratings on the adequacy of total adjustment, made at the time of each test, support the test evidence that the drugs administered to this group had little if any effect on their total adjustment to their environment.