Vitamin supplements and purported learning enhancement in mentally retarded children.

Dr. Ruth Harrell and her colleagues conducted a study in 1981 in which the administration of high dosages of vitamins were determined to dramatically improve the intellectual functioning of mentally retarded children. This paper documents the efforts of its authors to replicate the Harrell et al. research and, although no significant differences were found between active treatment groups and control groups at study's end, a thorough comparison is made between the two research efforts.