ANXIETY AND DEPRESSIVE SYMPTOMS IN CHILDHOOD - A GENETIC-STUDY OF COMORBIDITY

Anxiety and depressive symptoms commonly co-occur yet the underlying m echanisms for this covariation remain poorly understood. Genetic strat egies are a useful means of investigating whether the comorbidity of t wo sets of symptoms or disorders can be explained by the same aetiolog ical factors. In this paper we use a systematically ascertained sample of 172 twin pairs aged 8 to 16 years to examine the causes of covaria tion of maternally rated anxiety and depressive symptoms. The results suggest that most of the covariation can be explained by a common set of genes that influence anxiety and depressive symptoms. Some covariat ion between anxiety and depressive symptoms is also explained by envir onmental influences of the non-shared type. In addition, depressive sy mptoms also appear to be influenced by specific genetic factors.