University of Washington psychologists have discovered that adolescent girls who engage in behaviors such as cutting themselves have lower levels of serotonin, a hormone and brain chemical, in their blood. They also have reduced levels in the parasympathetic nervous system of what is called respiratory sinus arrhythmia, a measure of the ebb and flow of heart rate along with breathing.
"A low level of this measure of the parasympathetic nervous system is characteristic of people who are anxious and depressed and among boys who are delinquent. But this is the first study to show it among adolescent girls who engage in self-harming behavior," said Theodore Beauchaine, UW associate professor of psychology.
The findings come from a study that also uncovered sharp disparities in the number of self-harming events and suicide attempts reported by the girls and their parents.
The research, headed by Sheila Crowell, a UW psychology doctoral student, focused on girls because self-harming behavior affects females far more often than it does males. The study included 23 girls, ages 14 to 18, who engaged in what psychologists call parasuicidal behavior. Participants were included if they had engaged in three or more self-harming behaviors in the previous six months or five or more such behaviors in their lifetime. An equal number of girls of the same ages who did not engage this behavior were enrolled as a comparison group.
The adolescents in the parasuicide group reported far more incidents of self-harming behavior than did their parents. Individuals engaged in this kind of behavior between 11 and 839 times. Their parents, however, reported a range of 0 to 205 incidents.
Contact: Joel Schwarz
University of Washington