Given the high heritability estimates for most complex neurobiological disorders, current approaches to understanding etiology have primarily focussed on uncovering a genetic contribution to disease-onset. Whilst a number of novel susceptibility loci for disorders including Alzheimer’s disease, schizophrenia and autism have been uncovered using recent genome-wide association approaches, these loci account for only a small proportion of attributable risk and the mechanism behind their action remains unknown. There is growing recognition that epigenetic mechanisms are important in the etiology of complex disease, acting at the interface between the genome and the environment. Recent technological advances mean that it is now feasible to study epigenetic marks such as DNA methylation at base-pair resolution across the genome. In this talk I will present data from our group showing how dynamic epigenetic processes are involved in neuropsychiatric phenotypes, and can be influenced by environmental, genetic and stochastic factors. We propose a novel etiological approach to complex disease based on the integration of genetic and epigenetic information.