The strength of this project is that we demonstrated, for the first time, that 1) telomeres are shorter, 2) Tert expression is reduced, 3) telomerase activity is decreased in hippocampus of a rat genetic model of depression, and 4) lithium treatment increases expression of β-catenin and Tert and telomerase activity in the FSL rat hippocampus. The gene discussed is TERT; the disease is depressive disorder.