Girls at risk of depression have decreased brain volume

A study published in the Archives of General Psychiatry illustrates an important aspect of the biological component of depression. The authors set out to...

"...test the hypothesis that reduced hippocampal volume precedes and therefore may be implicated in the onset of depression."

The hippocampus is the 'seat' of short-term memory and regulates the adrenal rhythm of cortisol. It's well known that the hippocampal shrinkage occurs due to damage from high levels of cortisol that can occur in reaction to inflammation (autoimmune and allergic), blood sugar dysregulation and other stress demands. The authors examined 55 girls aged 9-15 years with voxel-based morphometry brain matter density estimates and traced hippocampal volume (MRI), 23 were high risk because of a maternal history of depression. What did the data show?

"Voxel-based morphometry analyses indicated that individuals at high risk of depression had significantly less gray matter density in clusters in the bilateral hippocampus than low-risk participants. Tracing yielded a volumetric reduction in the left hippocampus in the high-risk participants."

This is why factors that have an adverse effect on hippocampal integrity always considered in the functional approach to depression as noted in the Parents' Guide to Brain Health. The authors conclude:

"Compared with individuals at low familial risk of the development of depression, high-risk individuals have reduced hippocampal volume, indicating that neuroanatomic anomalies associated with depression may precede the onset of a depressive episode and influence the development and course of this disorder."

The most dependable way to know whether there are abnormalities in the regulation of cortisol amplitude and rhythm that may be associated with hippocampal damage is by easily measuring the free-fraction (bioactive) cortisol levels in four saliva samples easily collected over the day.