Attempts to establish a link between people's genes and their tendency to suffer from anxiety and depression have only been partially successful. A study of 3,107 people in Germany and the U.S. looked into the genetic origins of neuroticism. Neuroticism is a personality trait that reflects a tendency towards negative mood states and has been consistently associated with the likelihood of having symptoms of anxiety and depression. The study tested more than 420,000 genetic markers for their association with neuroticism. The most 'promising' gene for neuroticism, i.e. the one with the strongest link, was a gene called MAMDC1 on the 14th chromosome.
van den Oord, Edwin J.C.G. ... [et al] - Genomewide association analysis followed by a replication study implicates a novel candidate gene for neuroticism Archives of General Psychiatry September 2008, 65(9), 1062-1071