Stress changes brain size during psychosis
Research conducted at the Institute of Psychiatry, King’s College London, and published in the Journal of Clinical Psychiatry, reveals how stress affects factors involved in the growth and survival of neurons in the brain, responsible for higher functions of the brain such as thinking, learning and memory.
The research focussed on the hippocampus, one of the main brain structures involved in cognitive functioning and memory-related processes and found that biological systems involved in the stress response are responsible for a shrinking hippocampus in individuals affected by psychosis.
The research focused on individuals at the first episode of psychosis and on healthy controls of the same age, living in the same geographical area. The researchers investigated stress levels in their past and current situations, and their effect on one of the main factors involved in growth and survival of neurons (Brain-Derived Neurotrophic Factor, BDNF). The research revealed that individuals with first episode psychosis who experienced more childhood trauma and more recent stressors had lower levels of BDNF levels. Interestingly, the researchers also found that low levels of BDNF, combined with high levels of inflammatory markers and cortisol (two of the main biological factors increased during the stress response) highly correlate with the reduction in the volume of the hippocampus (measured by brain scan).
Lead author of the paper, Dr Valeria Mondelli, said: ‘These findings clarify the mechanisms behind deleterious effects of stress on the brain of individuals affected by psychosis. We are not only finding that stress, and in particular childhood trauma, affect biological systems involved in growth and survival of neurons, but we are also showing for the first time that three different biological systems affected by stress have an independent and cumulative role in determining brain structure abnormalities and in particular the smaller hippocampal volume observed in psychosis, already at the first episode of illness.’
This study is part of a larger study on first episode psychosis funded by the NIHR Biomedical Research Centre (BRC) for Mental Health at the South London and Maudsley NHS Foundation Trust & Institute of Psychiatry (SLaM) and the IoP at King’s. The study was jointly led by the senior authors Dr Carmine M. Pariante, at the Laboratory of Stress, Psychiatry and Immunology in the Department of Psychological Medicine, and Dr Paola Dazzan, at the Section of Early Psychosis, all based at IoP.
'Stress and Inflammation Reduce Brain-Derived Neurotrophic Factor Expression in First-Episode Psychosis: A Pathway to Smaller Hippocampal Volume' Mondelli et al, the Journal of Clinical Psychiatry.