Understanding wellbeing: its role in mental illness and cognition, and ways it can be promoted

Abstract

This thesis explores the genetic and environmental underpinnings of mental wellbeing in a large, healthy twin cohort. The first aim is to establish the shared and unique genetic and environmental influences between mental wellbeing and symptoms of depression and anxiety. The second aim is to explore the genetic and environmental contributions of wellbeing to emotion processing, and identify any shared variation with depression and anxiety symptoms. The third aim mirrors the second, but in respect of cognitive function. The final aim is to evaluate the effectiveness of an online training program targeting emotion processing and cognitive function in improving wellbeing and reducing symptoms of depression and anxiety. Modelling wellbeing and symptoms of depression and anxiety indicated that the two were independent constructs, highlighting the need for measures of mental health to capture wellbeing. Exploring the relationship between wellbeing and emotion processing revealed small genetically-driven relationships between identification of happy faces and both wellbeing and mental illness symptoms. In examining the relationship between cognitive function and mental health, results suggested that there were small, differentiated relationships with different aspects of cognitive function which were largely genetically-driven. Finally, results from the randomised controlled trial testing the brain training program found strongest effects for emotion bias training. Men showed a reduction in implicit fear and anger biases, which mediated significant reductions in depression and anxiety symptom severity. Both sexes also showed improvements in the explicit identification of fear expressions. There were no improvements in other trained tasks, save for a small preservation of executive function. In conclusion, mental wellbeing and symptoms of mental illness show differentiation at a genetic and environmental level, and in their pattern of associations with emotional and cognitive function. Brain training may result in limited improvements in function, particularly emotional function, and show some potential for mental health benefits in terms of reduction of depression and anxiety symptomology.