17 Jun Genetic Structures Underlying Depression and Anxiety During Development
MedicalResearch: What are the main findings of the study?
Answer: Little is known about the genetic influences on the relationship between depression and anxiety disorders across development. We used two population-based prospective longitudinal twin and sibling studies to investigate phenotypic associations between the symptoms of these disorders, and tested genetic structures underlying these symptoms across three developmental stages: childhood, adolescence and early adulthood.
We found that depression and anxiety disorder symptoms are largely distinct in childhood and are influenced by largely independent genetic factors. Depression and anxiety symptoms become more associated and shared most of their genetic etiology from adolescence. An overarching internalizing genetic factor influencing depression and all anxiety subscales emerged in early adulthood. These results provide preliminary evidence for different phenotypic and genetic structures of internalizing disorder symptoms in childhood, adolescence and young adulthood, with depression and anxiety becoming more associated from adolescence.
MedicalResearch: Were any of the findings unexpected?
Answer: This study was the first to look at the genetic structures underpinning depression and anxiety separately at three different developmental stages. Unexpectedly, we found that childhood, adolescence and adulthood are characterized by different phenotypic and genetic relationships between these symptoms. Previous literature suggested that childhood and adolescence depression may differ, but this is the first study that investigated these developmental changes with relation to a range of anxiety disorder symptoms comprehensively across development.
MedicalResearch: What should clinicians and patients take away from your report?
Answer: Our results support transdiagnostic treatment approaches for anxiety and depression disorders, which are designed to target common elements of several disorders in one protocol. While disorder-specific treatment may be more appropriate for pediatric patients, treatment focused on a range of symptoms common to internalizing disorders may be more appropriate for older patients. Finally, our findings affirm the need to continue examining the classification of mood and anxiety disorders in diagnostic systems.
MedicalResearch: What recommendations do you have for future research as a result of this study?
Answer: An overarching genetic internalizing factor provides preliminary support for broadening phenotypic definitions in molecular genetic studies in adult participants. However, future research should acknowledge that depression and anxiety can differ with age, and thus focus on more narrow age ranges across development. Future studies should also examine the longitudinal relationship between depression and a range of anxiety disorder symptoms, to investigate the degree of genetic continuity characterizing these symptoms.
Waszczuk MA, Zavos HS, Gregory AM, Eley TC. The Phenotypic and Genetic Structure of Depression and Anxiety Disorder Symptoms in Childhood, Adolescence, and Young Adulthood. JAMA Psychiatry. Published online June 11, 2014. doi:10.1001/jamapsychiatry.2014.655.