Increased aggressivity in toddlers due to abnormal functioning of nervous system and problems of pregnant mother

28 June 2017

Young children exhibit more aggressive behaviour if their nervous system does not respond adequately to stress situations and if they were exposed to risk factors of the mother during pregnancy, such as smoking or psychological problems. These are the conclusions of PhD researcher Jill Suurland. She will defend her doctoral thesis on 4 July. Her research was funded by the NWO temporary taskforce National Initiative Brain & Cognition (NIHC).

Boy crouched down, sad and angryPhoto Shutterstock by Sharomka

Factors for aggressive behaviour

Frequent fighting, deliberately hurting others and responding furiously to sadness or frustrations. Some children already exhibit problematic behaviour during early childhood. Pedagogue Jill Suurland investigated the neurobiological, emotional and cognitive factors of aggressive behaviour in young children.

Functioning nervous system disrupted

Her research has revealed that these children have difficulty in regulating their impulses and negative emotions, such as anger and frustration. In these children, the coordination within the autonomous nervous system is disrupted: the sympathetic and parasympathetic nervous systems do not work together properly. In response to stress, the sympathetic nervous system increases the breathing rate and heart rate. This is usually associated with a decrease of activity within the parasympathetic nervous system, which ideally is more active during rest and reduces the heart rate and breathing rate. In these children, however, that mechanism functions poorly; the sympathetic and parasympathetic nervous system are active or inhibited at the same time.

Problems pregnant mother

Suurland concludes that these children mainly exhibit problematic behaviour in combination with negative influences of the pregnant mother, such as smoking, psychological problems, and a high stress levels due to financial concerns or the absence of social support. This insight is important for a timely and satisfactory treatment of these children, she emphasises. Disproportional aggression in early childhood increases the chances of poor school performance, criminal behaviour and depression at a later age. The PhD researcher calls for a better identification of pregnant women with a high-risk profile so they can receive aid via preventative intervention groups. The mother and child can then receive proper support at an early stage.

Additional research needed

According to Suurland, additional research is needed because it is still not known to what extent treating the mother during the pregnancy and the infancy influences the physiological self-regulation of the child. According to her, a targeted early intervention is crucial. ‘Continuous aggressive behaviour among older children and adolescents is often difficult to treat using current intervention programmes.’

Long-term research among a large group of children

The PhD researcher studied the development of a large group of young children in the Mother-Infant NeuroDevelopment Study in Leiden. This is a longitudinal study in which 275 pregnant women and their children were monitored until the children reached 3.5 years of age. During the pregnancy, expectant mothers were screened for the presence of a large number of risk factors. In addition, she investigated 855 preschool children for cognitive predictors of aggressive behaviour.

Source: Leiden University