Counseling Services of Barbara Reade, L.C.P.C.
Bel Air, Maryland 21014

Phone: 410-803-1510

Email: reade.lcpc@yahoo.com  

STRESS AND THE DEVELOPING BRAIN

The early months and years of life are critical for brain development. A major question for researchers has been—how do early influences act on the brain to promote or challenge the developmental process? Research has suggested that many both positive and negative experiences, chronic stressors, and various other environmental factors may affect a young child's developing brain. And now, studies involving animals are revealing in greater detail how this may occur.

Important Stress research has focused on brain systems that control stress hormones—cortisol. Cortisol and other stress hormones play an important role in severe stress and emergency situations: these hormones help our bodies make energy available to enable effective responses, temporarily suppress the immune response, and sharpen attention. However, a number of studies conducted in people with depression indicate that excess cortisol released over a long time span may have many negative consequences for health. Excess cortisol may cause shrinking of the hippocampus, a brain structure required for the formation of certain types of memory.

In animal studies the capacity to handle stress throughout life is shown to be affected by early childhood nurturing. An NIH study shows that " …’when’ rat pups were removed each day from their mothers for a period as brief as 15 minutes and then returned the natural maternal response of intensively licking and grooming the returned pup was shown to alter the brain chemistry of the pup in a positive way, making the animal less reactive to stressful stimuli. While these pups are able to mount an appropriate stress response in the face of threat, their response does not become excessive or inappropriate.

Striking differences were seen in rat pups removed from their mothers for periods of 3 hours a day …compared to pups that were not separated. After 3 hours, the mother rats tended to ignore the pups, at least initially, upon their return. In sharp contrast to those pups that were greeted attentively by their mothers after a short absence, the "neglected" pups were shown to have a more profound and excessive stress response in subsequent tests. This response appeared to last into adulthood. "

In another study scientists have compared animals raised in an enriched environment and found that the "privileged" rats consistently have a thicker cerebral cortex and denser networks of nerve cells than the "deprived" animals.

"Another study recently reported that infant monkeys raised by mothers who experienced unpredictable conditions in obtaining food showed markedly high levels of cortiocotropin releasing factor (CRF) in their cerebrospinal fluid and, as adults, abnormally low levels of cerebrospinal fluid cortisol."

This is a pattern often seen in humans with post traumatic stress disorder and depression. The distressed parent monkeys, from the study above, often acted inconsistently with their offspring, resulting, sometimes, in neglect.

Human reaction appears to be quite similar. In recent studies from Mark Levine, M.D., at UCLA, adults with prolonged abusive or high stress living circumstances are clearly shown to have low levels of cortisol and shrinking of the hippocampus. Promisng studies of certain SSRI’s and SSNRI’s (antidepressant drugs), show that these drugs cause the lessening of shrinkage of this brain area, thus allowing patients to stop the mental spirals often associated with PTSD and depression.

In conclusion, significant stress in early childhood, or in adulthood, can have significant and long lasting effects, in the brain.