Familial Clustering of Major Depression and Anxiety Disorders in Australian and Dutch Twins and Siblings

Abstract

T he aim of this study was to investigate familial influences and their dependence on sex for panic disorder and/or agoraphobia, social phobia, generalized anxiety disorder and major depression. Data from Australian (N = 2287) and Dutch (N = 1185) twins and siblings who were selected for a linkage study and participated in clinical interviews to obtain lifetime Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) diagnoses were used. In a liability model, tetrachoric correlations were estimated in sibling pairs and sex differences between sibling correlations were tested. For each diagnosis, the sibling correlations could be constrained to be equal across the Australian and Dutch samples. With the exception of panic disorder and/or agoraphobia, all sibling correlations were the same for brother, sister and opposite-sex sibling pairs and were around .20. For panic disorder and/or agoraphobia, the correlation was .23 in brother and sister pairs, but absent in opposite-sex sibling pairs. From these results it can be concluded that upper heritability estimates, based on twice the correlations in the sibling pairs, vary between 36% (major depression) and 50% (social phobia). Furthermore, different genetic risk factors appear to contribute to the vulnerability for panic disorder and/or agoraphobia in men and women. No other sex differences were found.Anxiety disorders and major depression (MDD) are common disorders. In epidemiological studies, lifetime prevalences in women are found to be around 30% for some kind of anxiety disorders and around 20% for MDD (Bijl et al., 1998;Kessler et al., 1994). Although these prevalences are lower in men, they are still high with figures ranging between 14% and 19% for anxiety disorders and between 11% and 13% for MDD (Bijl et al., 1998;Kessler et al., 1994). These prevalences may be even higher as cross-sectional surveys are biased by recall problems. When recall bias is considered, the prevalence of lifetime MDD is estimated at 30% in men and 40% in women (Kruijshaar et al., 2005). These disorders constitute a huge public health problem, mainly due to the chronic and disabling course, but in the case of MDD, also as a result of the increased risk for other major diseases such as cardiac mortality (Musselman et al., 1998;Penninx et al., 2001).Consequently, the etiology of these disorders is an important topic of research. Over the last 20 years, several family and twin studies have been performed to investigate the influence of familial factors on anxiety and depression. In the description of the results, we will focus on MDD, panic disorder and/or agoraphobia, social phobia and generalized anxiety disorder (GAD). Sullivan et al. (2000) and Hettema, Neale, et al. (2001) discussed the results of family and twin studies on lifetime diagnoses of MDD and anxiety disorders respectively and performed a metaanalysis when possible. They included studies in which the disorders were defined by operationalized diagnostic criteria, such as the Diagnostic and Statistical Man...

Prevalence and heritability of obsessive‐compulsive spectrum and anxiety disorder symptoms: A survey of the Australian Twin Registry

“…When compared to studies that have assessed social phobia symptoms using the fear of negative evaluation scale, our heritability estimate is closest with regard to female twins (47% vs. 48%) [Stein et al, ]. While some studies have reported no heritable sex differences in fear and phobia (including social phobia) [Hettema et al, ; Middeldorp et al, ], another study reported that social phobia in males was explained by genetic risk factors and in females by familial‐environmental factors [Kendler et al, ]. However, two additional twin studies performed separately in males and females reported lower heritability in males (20%) [Kendler et al, ] than females (30%) [Kendler et al, ].…”

Suggestive linkage on chromosome 2, 8, and 17 for lifetime major depression

“…Although these samples are geographically disparate, we have shown previously that the genetic distance between these Dutch and Australian subjects (F st = 0.30%) is comparable to that between most Northern European populations [Sullivan et al, 2006]. Also, the genetic architecture of MDD is similar in the two countries with a heritability estimate for MDD of 36% and without evidence for sex differences in genetic architecture, allowing us to pool data from men and women in the linkage scan [Middeldorp et al, 2005].…”

Structure of genetic and environmental risk factors for dimensional representations of DSM–IV anxiety disorders

“…Our heritability estimates for panic disorder, GAD, phobia and OCD are similar to or slightly lower than those previously reported. [1][2][3][4][5][6][7][8] A meta-analysis of previous twin studies estimated heritabilities of 0.43 for panic disorder, 0.32 for generalised anxiety disorder and 0.20-0.37 for various types of phobias. 2 A review of twin studies on obsessive-compulsive disorders reported heritabilities of 0.27 to 0.47.…”