Door trauma bewogen: Tegenovergestelde effecten van trauma in de kindertijd en fysieke activiteit op psychologische en biologische processen in de ontwikkeling van psychiatrische klachten bij jongvolwassenen

Adolescence and young adulthood is a period of intense biological, psychological and social changes. It is also the period wherein individuals are most vulnerable to develop psychiatric symptoms and disorders. In this PhD thesis we examine one major risk factor and one major resiliency factor for the development of psychopathology, respectively childhood adversity and physical activity and exercise. We examine their effects on two potential underlying processes, namely self-esteem and self-esteem instability, a psychological factor, and hippocampal pattern separation or mnemonic discrimination, a biological factor.

Our results demonstrated that childhood adversity, psychopathology and self-esteem are intricately linked. Young adults who experienced childhood adversity have lower global self-esteem and higher self-esteem instability, which is less amenable to change when psychiatric symptoms increase or decrease. The clinical implication is that to enhance self-esteem (instability) in these individuals, more specific treatments are necessary in addition to reducing psychiatric symptoms. Furthermore, we found small effects of physical activity in daily life on self-esteem. Although small, these can be cumulative over time. In addition, state belongingness is strongly related to state self-esteem which opens up avenues for targeted intervention.

We showed that the effect of exercise on hippocampal pattern separation is subject to many possible biological influences, specifically neuroplastic, anti-inflammatory and hormonal mechanisms. However, we could not demonstrate an effect of exercise or psychiatric symptoms on hippocampal pattern separation or mnemonic discrimination in our sample of adolescents and young adults. Future research should further optimize the mnemonic discrimination task and bring coherence to the heterogeneous analytical possibilities in examining pattern separation. In addition, clinical correlates of the neurocomputational process should be established more clearly. New techniques in neuroscience may help advance the field of pattern separation.