Reinterpretation of the haematological effects of anticonvulsant treatment.

Blood-counts and folate assays were performed on samples from 102 adults at a residential institution for severe mental impairment. 96 of these patients were receiving anticonvulsant therapy and 6 were not. Only 1 subject had a macrocytic blood-picture, and 5 subjects had hypochromic anaemia. No features of incipient metaloblastic haemopoiesis were identified in the remaining samples. However, serum-folate measured by two assay methods was subnormal in 83% of the samples; red-cell folate was subnormal in 40%. It is concluded that the development of macrocytic anaemia in subjects on long-term anticonvulsants therapy is probably not related to the biochemical process which causes their low assayable folate but reflects inadequate nutrition.