Adult neurogenesis: implications for psychiatry.

The fields of psychiatry and neuroscience have formed a close relationship over the past decades. Hypotheses about the neurochemical basis of behavioral dysfunction helped in part to develop promising treatments for several psychiatric disorders, including depression, addiction and schizophrenia. In addition to advancing the neurochemical approach to psychiatric disorders, the relationship between psychiatry and neuroscience also fostered an appreciation for the role neuroanatomy plays in brain function and dysfunction. The productivity of this marriage between the brain structure and brain function approaches is evident in the large literature on neuroanatomical alterations associated with psychiatric disorders. In particular, altered morphology of limbic structures, such as the prefrontal cortex and hippocampus, has been associated with many psychiatric disorders. Depression, post-traumatic stress disorder (PTSD), dementia, schizophrenia and drug dependence have all been linked to decreased volume of limbic-related structures and altered hippocampal morphology (Carlen and Wilkinson, 1987; McEwen and Sapolsky, 1995; Sheline et al., 1996; Bartzokis et al., 2000; Benes and Berretta, 2000). Clini-