Ryan J. Herringa, M.D., Ph.D., Assistant Professor of Psychiatry at the University of Wisconsin-Madison, and 2012 NARSAD Young Investigator Grant recipient, conducted a study to investigate brain changes associated with childhood maltreatment experiences that can lead to the development of later psychiatric illness, particularly depression and anxiety.
The brain is most delicate and impressionable during childhood; it continues to physically develop not only in the first years of life but extending even beyond adolescence and into young adulthood. This is well documented, but it is not yet well understood what goes wrong in the brain when a young person is maltreated that can lead to the development of illness.
In this new study, Dr. Herringa worked with two-time (1995 and 2003) NARSAD Distinguished Investigator Grantee Richard J. Davidson, Ph.D., and other colleagues and found that connectivity in brain areas crucial in regulating fear and emotional memory is reduced in adolescents reporting childhood maltreatment experiences. The findings were reported November 4th in Proceedings of the National Academy of Sciences.
The research team studied a group of 64 “late adolescents” (aged 18) who had been followed from birth in the Wisconsin Studies of Families and Work (Principal Investigator: Marilyn Essex, Ph.D.). Abuse measures and adolescent anxiety and depression symptoms were self-reported by the participants and functional brain images were taken (structural and resting state) to allow for modeling of brain connectivity.
The researchers identified lower levels of connectivity between a portion of the lower prefrontal cortex and the hippocampus region of the brain in both males and females and, in females only, lower connectivity between the lower prefrontal cortex and the amygdala. These weaker brain connections, in turn, mediated the development of adolescent symptoms of anxiety and depression.
The findings are exciting in two respects. First, they suggest a clear and consistent biological liability linked directly with depression and anxiety in maltreated children. Second, they seem to indicate at least one possible cause for a fact long known: females are more likely than males to become depressed or anxious over the lifespan. Some of this difference may be due to hormonal activity; but as this study suggests, the additional impact of maltreatment on connectivity to the amygdala region in the brain in females may also help explain the difference.