Concurrent attenuated reactivity of alpha-amylase and cortisol is related to disruptive behavior in male adolescents

Abstract

Attenuated reactivity of salivary alpha-amylase has been proposed as a specific sympathetic marker of disruptive behavior in juveniles and may have additional value to studying other autonomic parameters and hypothalamic–pituitary–adrenal axis activity. Investigating the interrelationships between neurobiological parameters in relation to juvenile disruptive behavior may enhance insight into the complex mechanisms at play.We investigated salivary alpha-amylase, cortisol, heart rate (HR), and heart rate variability (HRV) in response to a standardized public speaking task, and examined interactions between these parameters in relation to disruptive behavior. Participants were 48 delinquent male adolescents (mean age 18.4years, SD 0.9), with and without a disruptive behavior disorder (resp. DP+, DP−) and 16 matched normal controls (NC). A structured psychiatric interview as well as the Youth Self Report and Child Behavior Checklist were administered to assess disruptive behavior.Alpha-amylase and cortisol reactivity, but not HR or HRV, showed significant inverse associations with dimensional measures of disruptive behavior. Moreover, both cortisol and alpha-amylase reactivity were significantly lower in the DP+ group as compared to the NC group. The mentioned relationships remained present when nicotine use was entered as a covariate. Combining alpha-amylase and cortisol in one model explained a larger part of the variance of disruptive behavior than either single parameter. There were no interactions between alpha-amylase and cortisol or HRV in relation to disruptive behavior.Attenuated alpha-amylase responsivity to stress is a correlate of disruptive behavior in late-adolescent males. Although nicotine use explains a considerable part of the variance of disruptive behavior, both alpha-amylase and cortisol are related to disruptive behavior, over and above the effect of nicotine use. Combining alpha-amylase and cortisol improved insight into neurobiological mechanisms involved with disruptive behavior; concurrent low reactivity of both parameters was related to higher levels of disruptive behavior.