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Saliva levels of hormone correlate with early, persistent aggression
In behavior-disordered children, a new study indicates, low saliva levels of the hormone cortisol are strongly associated with persistent, severe aggression beginning at an early age.
Keith McBurnett and colleagues evaluated 38 boys referred to a clinic, between the ages of 7 and 12, for problem behaviors. The children's behaviors were evaluated annually for four years, using structured interviews with the children and their parents an
nd teachers. During the first two years, the researchers also interviewed the children's classmates to determine which students in their classrooms fought the most and were considered the "meanest." Salivary cortisol level measurements were taken during t
the second and fourth years of the study.
McBurnett et al. report, "Low cortisol levels were associated with persistence and early onset of aggression..
Boys with lower cortisol concentrations at both time points exhibited triple the number of aggressive symptoms and were named as most aggressive by peers three times as often as boys who had higher cortisol concentrations at either sampl
ling time." All but one of the boys in the low-cortisol group had developed at least one symptom of conduct disorder by the age of ten, while those with high cortisol levels were evenly divided between late onset and early onset of symptoms.
Cortisol levels are one measure of the functioning of the hypothalamic-pituitary-adrenal (HPA) axis, and abnormal HPA functioning and feedback are linked to a number of mental disorders including depression. The researchers say the reason for elevated lev
vels of cortisol in their persistently aggressive subjects are unknown, but McBurnett speculates, "Children with persistent conduct disorder may have genes that predispose them to produce certain hormones differently, or their hormone production may have
been altered before or soon after birth."
While one study focusing on aggression and cortisol levels did not report findings similar to those of McBurnett and colleagues, the researchers note that several studies offer evidence that "the current findings are not isolated." Among them:
- One study of adults found that aggressive antisocial prisoners, and prisoners with histories of what is now defined as early-onset conduct disorder, had lower cortisol concentrations than other prisoners or non-incarcerated controls.
- Another study found that the salivary cortisol concentrations of teenagers were inversely related to the number of early conduct disorder symptoms the subjects had exhibited, and to a paternal history of lifelong conduct disorder or antisocial persona
ality disorder.
- A study of children with early-onset oppositional defiant disorder (ODD) found that these subjects had lower cortisol concentrations than children without ODD.
The researchers conclude that research supports the hypothesis that "boys with persistently low salivary cortisol concentrations have a markedly elevated risk of continuing in aggressive antisocial behavior."
Study of pregnant teens reports link between hormone, behavior
In earlier research, Elizabeth Susman and colleagues reported that in pregnant teenagers, lower concentrations of corticotropin-releasing hormone (CRH) in the blood are linked to an increased number of conduct disorder symptoms. In addition, pregnant teen
ns with low CRH concentrations exhibited more symptoms of depression. Like cortisol levels, CRH levels are an indicator of HPA function.
Susman noted, "We've identified a biological marker for antisocial behavior and depression in pregnant teens. While we don't know if the lower hormone concentrations make the teen vulnerable to conduct disorder or if, instead, antisocial behavior and depr
ression alter the concentration of the hormone, we do now have evidence that the hormone is associated with emotions and behavior during pregnancy."
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"Low salivary cortisol and persistent aggression in boys referred for disruptive behavior," Keith McBurnett, Benjamin B. Lahey, Paul J. Rathouz, and Rolf Loeber, Archives of General Psychiatry, Vol. 57, No. 1, January 2000, pp. 38-43. Address: Keit
th McBurnett, Department of Psychiatry, University of Chicago, 5841 S. Maryland Avenue, MC 3077, Chicago, IL 60637.
--and--
"Saliva test finds boys with taste for violence," Electronic Telegraph, January 17, 2000.
--and--
"Corticotropin-releasing hormone and cortisol: longitudinal associations with depression and antisocial behavior in pregnant adolescents," E. J. Susman, K. H. Schmeelk, B. K. Worrall, D. A. Granger, A. Ponirakis, and G. P. Chrousos, Journal of the Amer
rican Academy of Child and Adolescent Psychiatry, Vol. 38, No. 4, April 1999, pp. 460-467. Address: Elizabeth Susman, Department of Biobehavioral Health, Pennsylvania State University, University Park, PA 16802.
--and--
"Stress hormone tied to depression and conduct disorder in pregnant teens," press release,Pennsylvania State University, May 21, 1999.
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