Similar complexities are seen in the human literature: while some studies linked the Met allele with anxiety disorders in humans (Woo et al, 2002) (albeit sometimes in men (Pooley et al, 2007) or women (Enoch et al, 2003) only), others found no association (Niarchou et al, 2014), and a recent meta-analysis of studies linking COMT with anxiety-related traits indicated a male-specific association with the Val (ie, the high activity) allele (Lee and Prescott, 2014). This evidence concerns the gene COMT and anxiety disorder.