John M. Hettema Discusses Psychiatric Genetics Research
Fast Moving Front Commentary, January 2011
Article: A population-based twin study of the relationship between neuroticism and internalizing disorders
Authors: Hettema, JM;Neale, MC;Myers,
JM;Prescott, CA;Kendler, KS
John M. Hettema talks with ScienceWatch.com and answers a few questions about this month's Fast Moving Fronts paper in the field of Psychiatry/Psychology.
Why do you think your paper is highly cited?
This study examines a question that cuts across several areas of interest in psychiatry/psychology: personality, psychopathology, comorbidity, and genetic epidemiology, so its findings potentially have wide applicability.
Personality relates to the normal spectrum of individual differences in patterns of thoughts, feelings, and behaviors, while psychopathology describes psychiatric disorders, conditions in which there is thought to be a disturbance in some aspect of normal brain function (akin to a cardiac or kidney disorder). Comorbidity is the observation that some groups of disorders co-occur over the lifetime more often than expected by chance. Genetic epidemiology is the study of how and why disorders run in families.
Does it describe a new discovery, methodology, or synthesis of knowledge?
This study builds upon prior research that attempts to answer several related questions. First, to what extent are the associations between neuroticism (a personality trait) and risk for each of the depression and anxiety disorders explained by genetic versus environmental factors, i.e., what etiologic factors are behind the observed associations between neuroticism and these psychiatric conditions?
"I hope that psychiatric genetics research will deepen our understanding of how the brain malfunctions in psychiatric disorders, facilitating improvements and expansions of available treatments."
Second, to what extent do the genetic and environmental factors underlying neuroticism account for, or help explain, comorbidity amongst these disorders?
Third, are there genetic and environmental factors independent of neuroticism that also contribute to their comorbidity?
Would you summarize the significance of your paper in layman's terms?
Depression and anxiety disorders are quite common and tend to occur together. Neurotic personality traits have long been observed to correlate with these, but this is the first study to dissect this relationship into genetic and non-genetic causes. By clearly demonstrating that the genetic factors underlying individual differences in neuroticism substantially overlap with those that increase risk for a wide range of psychiatric disorders, we can use this in strategies for identifying which individual genes are involved in these conditions.
How did you become involved in this research, and how would you describe the particular challenges, setbacks, and successes that you've encountered along the way?
I was quite fortunate to have landed at Virginia Commonwealth University (VCU) for my medical training, as that exposed me to their world-renown psychiatric genetics research program. That exposure, together with the interest I developed in anxiety disorders during my clinical training, has led me to devote my research efforts to understanding the causes of these conditions that cause substantial distress and impairment to those who suffer from them.
The major challenges in pursuing this type of research are (1) the need to integrate a broad body of knowledge and scientific approaches, and (2) having access to large, comprehensively assessed, genetically informative samples. Both of these have been facilitated though my work at VCU.
Where do you see your research leading in the future?
I have been using the findings of this study, that is, shared genetic risk among neuroticism and anxiety disorders and depression, in follow-up studies that attempt to identify specific genes that increase an individual’s risk for developing these conditions. I have such projects currently underway.
Do you foresee any social or political implications for your research?
I hope that psychiatric genetics research will deepen our understanding of how the brain malfunctions in psychiatric disorders, facilitating improvements and expansions of available treatments.
John M. (Jack) Hettema, M.D., Ph.D.
Associate Professor of Psychiatry
Virginia Institute for Psychiatric and Behavioral Genetics
Virginia Commonwealth University
Richmond, VA, USA
KEYWORDS: GENERALIZED ANXIETY DISORDER; EQUAL-ENVIRONMENT ASSUMPTION; ADULT PSYCHIATRIC-DISORDER; COMMON MENTAL-DISORDERS; MAJOR DEPRESSION; GENETIC EPIDEMIOLOGY; LINKAGE ANALYSIS; WOMEN; PERSONALITY; COMORBIDITY.