background Comorbidity is widely seen between different psychiatric and substance use disorders in both clinical and epidemiologic samples. An important question is the degree to which these patterns emerge as a result of the impact of genetic versus environmental reasons.
aim To clarify the contribution of genetic and environmental risk factors to patterns of comorbidity in epidemiologic samples. methods Personal assessment of lifetime history of axis I and axis II psychiatric disorders and substance use disorders in population based twin samples from Virginia (usa) and Norway. Analysis using multivariate twin methods in the software package Mx.
results We will explore the results of multivariate analyses of phobias, common internalizing and externalizing psychiatric disorders and substance use disorders in twins from the Virginia Twin Registry and personality disorders from the niph Norwegian Twin Registry.
conclusion Genetic factors contribute substantially to patterns of comorbidity of psychiatric and substance use disorders. The impact of genetic risk factors rarely follows our diagnostic categories. More commonly, genetic risk factors impact on a range of disorders. Genes do not appear to have read or particularly respect dsm-iv or icd-10.