Characterising the relationship between fatigue and depression

This dissertation focused on increasing our knowledge and understanding of the
comorbidity and genetics of fatigue and depression. Statistical computations, including twin modelling and analysis of genome-wide association data, were conducted to characterise the phenotypic and genetic relationship between fatigue and depression. The high levels of comorbidity observed between fatigue and depression is independent of the traits overlapping symptoms and is likely attributable to the non-causal genetic relationship which exists between the traits. Whereby, a significant proportion of the association between fatigue and depression is explained by shared genetic factors.