That's according to Graeme Fairchild, PhD, of the psychiatry department at England's Cambridge University.
In a new study, Fairchild and colleagues studied 165 male teens, 70 of whom had conduct disorder, which can include rule-breaking and aggressive, destructive, or deceitful behavior.
The teens provided saliva samples throughout the day, including after experiments designed to frustrate and provoke them (such as a playing a doomed-to-lose game with a taunting opponent).
The researchers measured levels of the stress hormone cortisol in the teens' saliva samples, and they monitored the teens' heart rates during the stress-inducing experiments.
Stress typically raises cortisol levels and heart rates. But in Fairchild's study, heart rates and salivary cortisol levels didn't spike as high in teens with conduct disorder, compared to the other teens.
But emotionally, it was a different story. Stress worsened the moods of all of the teens, regardless of conduct disorder.
The finding "suggests poorer coordination between emotional and physiological arousal" in male teens with conduct disorder while under stress, Fairchild and colleagues write.
It's not clear from the study which came first -- conduct disorder or less physical reactivity to stress. Past research on cortisol and conduct disorder has had mixed results, Fairchild's team notes.
"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 behavior problems," Fairchild says in a news release.
The study appears in the Oct. 1 edition of Biological Psychiatry.