A Leu34Phe mutation in the cocaine- and amphetamine-regulated transcript (CART) gene has been associated with severe early-onset obesity in an affected family. It has been shown that, in a cell culture system, the mutation resulted in altered CART peptide levels, and animal studies suggest that CART is involved in anxiety as well. The availability of the affected family allowed for testing of anxiety and other traits in humans carrying a mutation in CART gene. This study shows that a small group of adolescents with the mutation exhibit higher anxiety and depression scores than control subjects.