What's my AGE again? Oxidative and other stress markers across psychiatric disorders

Schizophrenia-spectrum disorders and affective disorders (depressive and anxiety disorders) are thought to arise from a wide range of biological, sociodemographic and psychological factors. Many predisposing factors are thought to add to ‘allostatic load’ or the long-term cumulative result of the adaptation of the body to environmental stressors. This thesis describes the relationship between schizophrenia-spectrum disorders and affective disorders and several biomarkers indicating a biological stress response.
The main biomarker investigated in this thesis is a skin autofluorescence (SAF)-measurement indicating advanced glycation end products (AGEs) [SAF-AGEs] as marker of cumulative oxidative stress. SAF-AGE level was increased in cases with recent onset psychosis, indicating more cumulative exposure to oxidative stress, was associated with a smaller hippocampal volume in psychosis. SAF-AGE level was not associated to self-reported positive symptoms, indicating that excessive oxidative stress is not involved in the development of psychosis-like experiences. SAF-AGE level was also associated with presence of affective disorder, especially major depressive disorder. Excess mortality associated with affective disorders was partly explained by higher SAF-AGE levels indicating excessive oxidative stress. Additionally, heart rate variability and baroreflex sensitivity were assessed to investigate the role of regulation of the autonomic nervous system in the association between ethnic discrimination and depressed mood. Although associated with depressed mood, autonomic dysregulation did not explain the relation between ethnic discrimination and depressed mood.
The results of this thesis emphasize the need for lifestyle intervention and (the development of) pharmacological anti-oxidant interventions in schizophrenia-spectrum disorders and affective disorders, aiming not only to improve physical health outcomes, but also to alleviate psychiatric symptoms.