A new study has found that adolescents exposed to violence exhibit biological changes that could affect their physical and emotional health for years to come. These biological changes occurred whether the teenagers were witnesses or victims. The study, in the Annals of Behavioral Medicine, found that high school students exposed to violence had higher blood pressure, higher heart rates and higher levels of cortisol (a "fight or flight" hormone that is involved in many important body functions).
"The risk factors of higher blood pressure, heart rate and cortisol have been associated with cardiovascular problems later in life such as hypertension and atherosclerosis," says study co-author Edith Chen, of the University of British Columbia.
The study involved interviewing the participants about their exposure to violence and if they were concerned about violence in their lives. They were also asked about the frequency, proximity and severity of the violence. Then, heart rate, blood pressure and cortisol levels were recorded both after the students watched serene nature scenes and after they performed a stress task — either a debate with an experimenter or a verbal puzzle. The more violence that had previously been experienced, the higher their blood pressure, heart rates and cortisol levels rose.
Additionally, cardiovascular responses were decreased as exposure to violence rose, suggesting a "numbing" effect - the more exposure; the less the teenagers reacted to it on cardiovascular testing. Chen says that this numbing response "suggests a deregulated physiological system, such that individuals may not be able to mount appropriate physical responses to future stressors they encounter in later life."
It also seems that race plays a part. White adolescents reported lower rates of exposure to violence than did African-American adolescents and the white students had lower baseline heart rate variability and higher cortisol levels than the African-American students.
Chen said the results indicated that violence could have long term detrimental effects on the hormonal and cardiovascular systems of teens. "Our results suggest that exposure to violence can be conceptualized as a chronic stressor that is internalized and has lasting effects on basal neuroendocrine and cardiovascular systems," she concluded.
