Inconsistent results were found regarding the association between the BDNF Val66Met polymorphism and cognitive function in BD; one suggested a non-significant association56, one said that those with Val/Val genotypes performed better31, two said that those with the Met allele performed worse57, 58, and two attribute the worse performance of BD patients with the Met allele to the smaller hippocampus volumes of patients with the Val/Val genotype32, 58. Here, BDNF is linked to Behcet disease.