OBJECTIVES:To evaluate electrodermal activity (EDA) as a prospective biomarker of treatment response, to determine whether patterns of EDA are altered by treatment, and to assess oppositional defiant disorder (ODD) as a possible moderator of trajectories in EDA after an empirically supported behavioral intervention for attention-deficit hyperactivity disorder (ADHD) in preschool.METHOD:Nonspecific fluctuations (NSFs) in skin conductance, which index sympathetic nervous system activity, were assessed among 4-6 year old children with ADHD (n = 99) before they participated with their parents in 1 of 2 versions of the Incredible Years intervention. All were reassessed at posttreatment, and a subgroup (n = 49) were assessed again at 1-year follow-up.RESULTS:No difference in pretreatment NSFs was observed between ADHD participants and a group of normal control children (n = 41). Nevertheless, among those with ADHD, fewer NSFs at pretest predicted poorer treatment response on 4 of 7 externalizing outcomes. Furthermore, treatment was associated with increasing NSFs across time, but not for those who scored high on ODD at pretest.CONCLUSIONS:Low EDA appears to mark resistance to treatment among preschoolers with ADHD. Furthermore, although our study was not experimental, treatment was associated with longitudinal increases in EDA, which were not observed in a normal control group. This may suggest increased sensitivity to discipline, with positive implications for long term outcome. In contrast to treated participants as a whole, however, those who scored high on ODD at pretest exhibited reduced EDA over time. (PsycINFO Database Record

OBJECTIVETo evaluate measures of cardiac activity and reactivity as prospective biomarkers of treatment response to an empirically supported behavioral intervention for attention-deficit/hyperactivity disorder (ADHD).METHODCardiac preejection period (PEP), an index of sympathetic-linked cardiac activity, and respiratory sinus arrhythmia (RSA), an index of parasympathetic-linked cardiac activity, were assessed among 99 preschool children (ages 4-6 years) with ADHD both at rest and in response to behavioral challenge, before participants and their parents completed 1 of 2 versions of the Incredible Years parent and child interventions.RESULTSMain effects of PEP activity and reactivity and of RSA activity and reactivity were found. Although samplewide improvements in behavior were observed at posttreatment, those who exhibited lengthened cardiac PEP at rest and reduced PEP reactivity to incentives scored higher on measures of conduct problems and aggression both before and after treatment. In contrast, children who exhibited lower baseline RSA and greater RSA withdrawal scored lower on prosocial behavior before and after treatment. Finally, children who exhibited greater RSA withdrawal scored lower on emotion regulation before and after treatment.CONCLUSIONSWe discuss these findings in terms of (a) individual differences in underlying neurobiological systems subserving appetitive (i.e., approach) motivation, emotion regulation, and social affiliation and (b) the need to develop more intensive interventions targeting neurobiologically vulnerable children.

Opposing theories of striatal hyper- and hypodopaminergic functioning have been suggested in the pathophysiology of externalizing behavior disorders. To test these competing theories, the authors used functional MRI to evaluate neural activity during a simple reward task in 12- to 16-year-old boys with attention-deficit/hyperactivity disorder and/or conduct disorder (n = 19) and in controls with no psychiatric condition (n = 11). The task proceeded in blocks during which participants received either (a) monetary incentives for correct responses or (b) no rewards for correct responses. Controls exhibited striatal activation only during reward, shifting to anterior cingulate activation during nonreward. In contrast, externalizing adolescents exhibited striatal activation during both reward and nonreward. Externalizing psychopathology appears to be characterized by deficits in processing the omission of predicted reward, which may render behaviors that are acquired through environmental contingencies difficult to extinguish when those contingencies change.