Low cortisol link to aggression and PTSD

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Hormone Linked to Severe Aggression in Boys

Archives of General Psychiatry 2000;57. NEW YORK, Jan 13 (Reuters Health)

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Low levels of a stress hormone may be an underlying cause of serious,

persistent aggression in young boys with behavioral problems, the results of

a new study suggest.

Among 7- to 12-year-old boys with behavioral problems, those who had low

levels of the hormone cortisol were three times more aggressive and three

times more likely to be considered the meanest kids by their classmates than

boys with higher levels of the hormone.

" Kids become aggressive for all kinds of reasons, but there seems to be an

association between starting (aggressive behavior) early and staying

aggressive... that seems to be associated with low cortisol, " the study's

lead author, Dr. McBurnett, of the University of Chicago, Illinois,

told Reuters Health in an interview.

While many children and teens go through a rebellious stage, there is a

group of children whose aggressive behavior starts early and continues into

adulthood, according to McBurnett.

" These are kids who have a basic difference in their temperaments, " he said.

According to the results of the study, these children with severe aggression

tend to have low levels of cortisol, McBurnett noted.

In the study, the investigators gathered data on 38 boys who showed

aggressive problem behavior, such as being cruel to other people or animals,

initiating fights, stealing from others or forcing others into sexual

activity. Each year for 4 years, the boys underwent examinations in which

they were evaluated for signs of aggressiveness. During the second and

fourth exams, levels of cortisol in saliva were measured.

Besides the professional evaluations and interviews with parents and

teachers, the children were also judged by their peers. During the first 2

years, their classmates were asked to rate the behavior of all students,

including naming the nicest, the meanest and the shyest student, as well as

the one who got into the most fights.

At the end of 4 years, there was a clear relationship between low cortisol

levels and aggressive behavior, the authors report in the January issue of

the Archives of General Psychiatry. About one-third of boys with low

cortisol levels were voted the meanest kid in class, compared to just

one-tenth of the boys with higher cortisol levels. In addition, boys who had

low cortisol levels were more likely to become aggressive at a younger age.

Exactly how cortisol relates to behavior is uncertain, but researchers

suggest that low levels of the hormone may affect how some aggressive

children respond to stress. According to McBurnett's team, it is unclear

what causes the stress-control system to go awry — genetics, some sort of

stress in the womb or during infancy, poor parenting, deprivation or some

other factor may be responsible.

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Low Cortisol Levels May Predict PTSD Risk

This study may be found in the August 2000 issue of The American Journal of

Psychiatry (157:1252-1259) : " Low Cortisol and Risk for PTSD in Adult

Offspring of Holocaust Survivors, " Yehuda, R, et. al. Click here to obtain a

copy. For Holocaust resources, please see The Holocaust from About's 20th

Century History Guide, Rosenberg.

Researchers at the Veterans Affairs Medical Center (VAMC) in Bronx, NY, have

been studying post-traumatic stress disorder (PTSD) in children of Holocaust

survivors. A major conclusion of these studies is that these children have a

higher risk of developing PTSD than other people. In the most recent study,

led by Yehuda, PhD, the research group discovered that adult children

with at least one parent who is a Holocaust survivor have low cortisol

levels. The discovery could mean that low cortisol levels may be predictive

of the development of PTSD.

Cortisol is a hormone that scientists associate with stress as well as

chronic mood disorders. During times of stress, cortisol levels rise and

then subside as the stress subsides. If stress is chronic or if a chronic

mood disorder (anxiety, depression) is present, increased cortisol levels

may indicate that the brain has become resistant to cortisol's effects,

scientists believe.

One may wonder why, then, people with PTSD or the risk of developing PTSD

would have lower cortisol levels. The VAMC research group theorizes that

with PTSD, the brain may become hypersensitive to the effects of cortisol.

The same area of the brain which may resist cortisol in people with chronic

mood disorders, the hypothalamic-pituitary-adrenal (HPA) axis, appears to

work differently in people with PTSD or the risk of having PTSD.

The study performed by the researchers at the VAMC involved 35 adult

children of Holocaust survivors and 15 comparison subjects. All subjects

were evaluated using various standard questionnaires. To determine whether

the subjects' parents had PTSD, parents were interviewed directly (in 11

cases) or subjects completed a questionnaire created by the researchers. To

test cortisol levels, urine samples were collected during 24-hour periods

during times when subjects did not expect to be under stress.

Using the results of the questionnaire, researchers divided the subjects

into three categories --

· subjects without lifetime PTSD, whose parents did not have PTSD

· subjects without lifetime PTSD, whose parents did have PTSD

· subjects with lifetime PTSD, whose parents did have PTSD

Researchers made the following conclusions based on the questionnaires and

tests --

· Adult children of Holocaust survivors were more at risk of developing PTSD

than the comparison subjects, even though lifetime traumatic experiences did

not differ between these two groups.

· 13 of the 35 offspring of Holocaust survivors had lifetime or current

PTSD.

· 25 offspring of Holocaust survivors had at least one parent with PTSD.

· Cortisol levels were low in subjects with PTSD and who had a parent with

PTSD, but where higher in subjects who had neither.

Ultimately, the researchers were able to determine that the low cortisol

levels were associated with parental PTSD rather than the parent's exposure

to trauma during the Holocaust. Additionally, the low cortisol levels could

be associated with a risk of developing PTSD. Subjects exposed to trauma

without developing PTSD did not necessarily have low cortisol levels, so

exposure to trauma alone cannot be associated with lower cortisol levels.

The conclusions of the VAMC study will help scientists further understand

PTSD and lead to newer treatments. By determining physiological differences

in people who develop PTSD, researchers can understand why some people

develop the disorder after traumatic experiences but others do not.