UK researchers discovered that antisocial behaviour may have a biological basis rooted in the inability of some male adolescents to have normal stress responses that help regulate circulating levels of the stress hormone cortisol causing them to behave less cautiously and with more anger and impulsiveness at times of stress.
The study was led by Dr Graeme Fairchild and Professor Ian Goodyer of the Developmental Psychiatry Section in the Department of Psychiatry at Cambridge University, and is published online in the journal Biological Psychiatry.
When people are under stress, for example when giving a public speech or presentation, sitting an exam or waiting for an operation, their levels of circulating cortisol go up. This causes stronger memories that make people more cautious and more capable of regulating their emotions, such as temper, anger, and violent impulses, the next time they feel stressed.
Fairchild and Goodyer and colleagues found that under stress, adolescent males with severe antisocial behaviour or conduct disorder do not experience the same increase in circulating cortisol as their counterparts who do not have antisocial behaviour.
For the study, the researchers recruited adolescent male participants from schools, pupil referral units and the youth offending service. 42 of them had early onset conduct disorder, 28 had adolescent onset conduct disorder, and 95 had no conduct disorder (the controls).
To establish resting levels of cortisol at different times of the day, the researchers took samples of saliva from each teenager at different times over several days, while they were in non-stressful situations.
The researchers then took saliva samples of the participants before, during and after they took part in a psychosocial activity that was designed to frustrate them, to establish the levels of circulating cortisol under these conditions.
The results showed that:
- There were no differences among the three groups in morning cortisol levels or the size of the cortisol awakening response.
- Basal cortisol levels in the evening (non stressful conditions) and at 11 am during the laboratory visit (just before the frustration experiment) were higher in both the early onset and the adolescent onset conduct disorder group compared to the controls.
- But, both cortisol and cardiovascular respones to the psychosocial stress activity were lower in both conduct disorder groups compared to controls.
- All three groups reported similar increases in negative mood under stress conditions.
Fairchild and Goodyer and colleagues concluded that:
“Our findings suggest that group differences in cortisol secretion are most pronounced during stress exposure, when participants with CD [conduct disorder] show cortisol hyporeactivity compared with control subjects.”
“There was no evidence for reduced basal cortisol secretion in participants with CD [conduct disorder], but rather increased secretion at specific time points. The results do not support developmentally sensitive differences in cortisol secretion between CD [conduct disorder] subtypes.”
The researchers said in a separate statement that the findings suggest antisocial behaviour may be partly due to mental illness caused by a chemical imbalance of cortisol in the brain and the body. The study reinforces the idea that antisocial behaviour or conduct disorder is more biologically based than many of us might think, in the same way as some people are more biologically predisposed to anxiety or depression.
Fairchild said:
“If we can figure out precisely what underlies the inability to show a normal stress response, we may be able to design new treatments for severe behaviour problems. We may also be able create targeted interventions for those at higher risk.”
“A possible treatment for this disorder offers the chance to improve the lives of both the adolescents who are afflicted and the communities in which they live,” he added.
“Cortisol Diurnal Rhythm and Stress Reactivity in Male Adolescents with Early-Onset or Adolescence-Onset Conduct Disorder.”
Graeme Fairchild, Stephanie H.M. van Goozen, Sarah J. Stollery, Jamie Brown, Julian Gardiner, Joe Herbert, Ian M. Goodyer.
Biological Psychiatry, Volume 64, Issue 7, 1 October 2008, Pages 599-606.
doi:10.1016/j.biopsych.2008.05.022
Source: Journal abstract, University of Cambridge .
Written by: Catharine Paddock, PhD.