Aggressiveness and hyperactive behaviour as related to adrenaline excretion

Abstract

The central question concerns the relationship between aspects of behaviour and physiological reactions. Measures of sympathetic‐adrenal activity in terms of adrenaline excretion in a normal and a stressful situation as well as teacher ratings of behaviour were analysed for a representative group of 86 boys aged 13. Adrenaline excretion was in both situations significantly negatively related to ratings of aggressiveness, motor restlessness, and concentration difficulties and also to the sum of the latter two, used as an indicator of hyperactive behaviour. The association between hyperactive behaviour and adrenaline excretion persisted in the stressful situation when aggressiveness was controlled, whereas there was no significant relationship between aggressiveness and adrenaline output when hyperactive behaviour was controlled. Furthermore, hyperactive boys differed significantly from non‐hyperactive boys in displaying lower adrenaline excretion in both situations. The results are discussed in terms of low sympathetic‐adrenal reactivity to external demands as a risk factor and as a possible indicator of vulnerability for social and/or pervasive conduct disturbances.