Genes,environment and their interplay in the development of psychopathological characteristics and their neuroimaging correlates in general population

The present dissertation, which can be framed in the fields of behavioural and psychiatric genetics, was aimed to study how early environmental factors such as parental negativity and childhood adversity, directly or in interaction with genetic factors account for psychopathological variation (subclinical and clinical psychiatric symptoms) in general populatiol including childhood behavioural problems, adult psychotic, depressive and anxious symptoms and their neuroimaging correlates. Furthermore, from the different studies included in this dissertation, additional research questions were also explored. The studies included in the thesis were based in singletons and twins samples. We found evidence indicating that child behaviour problems, anxious and depressive symptoms and psychotic experiences (PEs) were present in our samples drawn from the general population which is in agreement with a dimensional approach to psychopathology. Furthermore, using neuroimaging techniques, we were able to find structural brain correlates of vulnerability for anxiety and depression in a MZ twin sample from the general population. Also, psychotic experiences were associated with brain activation to facial emotion in this MZ twin sample. In regard to the specific environmental factors studied (parental negativity and childhood maltreatment), experiences occurring early in life showed to be associated to adolescent behaviour problems and adult psychotic experiences highlighting the enduring effects of exposure to childhood adversity. These results highlight the relevance of early adversity in the understanding of psychopathological features. Finally, our findings provide evidence of different ways through genes, environment and their interplay can modulate the final expression of the phenotype. Thus, while there is no doubt regarding that genes and environmental factors can have a direct influence in the phenotype, there is a gene-environment interdependence that must be considered when studying the etiology of complex characters