Bipolar spectrum in major depressive disorders.

Growing evidence for the spectrum concept of most mental disorders, particularly mood disorders, has challenged the arbitrary distinctions inherent in the contemporary categorical diagnostic classification system. Detection of manic symptoms in the context of episodes of depression is particularly important because of the implications for differential treatment of bipolar vs unipolar depression. The purpose of this study is to characterize the magnitude and clinical correlates of subthreshold manic syndromes or symptoms among people with major depressive disorder (MDD) compared to those without a history of manic symptoms. We defined two subthreshold manifestations-manic syndrome or symptoms-that did not include a criterion for duration. In the context of MDD, we found that the clinical correlates of those with the subthreshold manic syndrome were more similar to those with bipolar-II disorder than to MDD alone, whereas those with manic symptoms only were intermediate between those with subthreshold manic syndrome and MDD alone. These results confirm the spectrum concept of mania and suggest that a manic syndrome should be considered when evaluating people with MDD.

Mood disorders and circulating levels of inflammatory markers in a longitudinal population-based study.

BACKGROUND: There has been increasing evidence that chronic low-grade inflammation is associated with mood disorders. However, the findings have been inconsistent because of heterogeneity across studies and methodological limitations. Our aim is to prospectively evaluate the bi-directional associations between inflammatory markers including interleukin (IL)-6, tumor necrosis factor (TNF)-α and high sensitivity C-reactive protein (hsCRP) with mood disorders. METHODS: The sample consisted of 3118 participants (53.7% women; mean age: 51.0, s.d. 8.8 years), randomly selected from the general population, who underwent comprehensive somatic and psychiatric evaluations at baseline and follow-up (mean follow-up duration = 5.5 years, s.d. 0.6). Current and remitted mood disorders including bipolar and major depressive disorders (MDD) and its subtypes (atypical, melancholic, combined atypical and melancholic, and unspecified) were based on semi-structured diagnostic interviews. Inflammatory biomarkers were analyzed in fasting blood samples. Associations were tested by multiple linear and logistic regression models. RESULTS: Current combined MDD [ß = 0.29, 95% confidence interval (CI) 0.03-0.55] and current atypical MDD (ß = 0.32, 95% CI 0.10-0.55) at baseline were associated with increased levels of hsCRP at follow-up. There was little evidence for inflammation markers at baseline predicting mood disorders at follow-up. CONCLUSIONS: The prospective unidirectional association between current MDD subtype with atypical features and hsCRP levels at follow-up suggests that inflammation may be a consequence of this condition. The role of inflammation, particularly hsCRP that is critically involved in cardiovascular diseases, warrants further study. Future research that examines potential influences of medications on inflammatory processes is indicated.

The role of genetic liability in the association of urbanicity at birth and during upbringing with schizophrenia in Denmark.

BACKGROUND: Studies have indicated that the association of urbanicity at birth and during upbringing with schizophrenia may be driven by familial factors such as genetic liability. We used a population-based nested case-control study to assess whether polygenic risk score (PRS) for schizophrenia was associated with urbanicity at birth and at age 15, and to assess whether PRS and parental history of mental disorder together explained the association between urbanicity and schizophrenia. METHODS: Data were drawn from Danish population registries. Cases born since 1981 and diagnosed with schizophrenia between 1994 and 2009 were matched to controls with the same sex and birthdate (1549 pairs). Genome-wide data were obtained from the Danish Neonatal Screening Biobank and PRSs were calculated based on results of a separate, large meta-analysis. RESULTS: Those with higher PRS were more likely reside in the capital compared with rural areas at age 15 [odds ratio (OR) 1.19, 95% confidence interval (CI) 1.01-1.40], but not at birth (OR 1.09, 95% CI 0.95-1.26). Adjustment for PRS produced almost no change in relative risks of schizophrenia associated with urbanicity at birth, but slightly attenuated those for urban residence at age 15. Additional adjustment for parental history led to slight attenuation of relative risks for urbanicity at birth [incidence rate ratio (IRR) for birth in capital = 1.54, 95% CI 1.18-2.02; overall p = 0.016] and further attenuation of relative risks for urbanicity at age 15 (IRR for residence in capital = 1.32, 95% CI 0.97-1.78; overall p = 0.148). CONCLUSIONS: While results regarding urbanicity during upbringing were somewhat equivocal, genetic liability as measured here does not appear to explain the association between urbanicity at birth and schizophrenia.

Dysregulation of objectively assessed 24-hour motor activity patterns as a potential marker for bipolar I disorder: results of a community-based family study.

There has been a growing number of studies that have employed actigraphy to investigate differences in motor activity in mood disorders. In general, these studies have shown that people with bipolar disorders (BPDs) tend to exhibit greater variability and less daytime motor activity than controls. The goal of this study was to examine whether patterns of motor activity differ in euthymic individuals across the full range of mood disorder subtypes (Bipolar I (BPI), Bipolar II (BPII) and major depression (MDD)) compared with unaffected controls in a community-based family study of mood spectrum disorders. Minute-to-minute activity counts derived from actigraphy were collected over a 2-week period for each participant. Prospective assessments of the level, timing and day-to-day variability of physical activity measures were compared across diagnostic groups after controlling for a comprehensive list of potential confounding factors. After adjusting for the effects of age, sex, body mass index (BMI) and medication use, the BPI group had lower median activity intensity levels across the second half of the day and greater variability in the afternoon compared with controls. Those with a history of BPII had increased variability during the night time compared with controls, indicating poorer sleep quality. No differences were found in the average intensity, variability or timing of activity in comparisons between other mood disorder subgroups and controls. Findings confirm evidence from previous studies that BPI may be a manifestation of a rhythm disturbance that is most prominent during the second half of the day. The present study is the largest study to date that included the full range of mood disorder subgroups in a nonclinical sample that increases the generalizability of our findings to the general community. The manifestations of activity patterns outside of acute episodes add to the accumulating evidence that dysregulation of patterns of activity may constitute a potential biomarker for BPD.

Reexamining associations between mania, depression, anxiety and substance use disorders: results from a prospective national cohort.

Separate inheritance of mania and depression together with high rates of clinical overlap of mania with anxiety and substance use disorders provide a basis for re-examining the specificity of the prospective association of manic and depression episodes that is a hallmark of bipolar disorder. We analyzed information from 34 653 adults in Waves 1 and 2 of the National Epidemiologic Survey on Alcohol and Related Conditions, a longitudinal nationally representative survey of US adults interviewed 3 years apart. Psychiatric disorders were assessed by a structured interview. We used logistic regression analyses to estimate the strength of associations between Wave 1 manic episodes and Wave 2 depression, anxiety and substance use disorders controlling for background characteristics and lifetime Wave 1 disorders. Corresponding analyses examined associations between Wave 1 major depressive episode with manic episodes and other psychiatric disorders. In multivariable models, Wave 1 manic episodes significantly increased the odds of Wave 2 major depressive episodes (adjusted odds ratio (AOR): 1.7; 95% confidence interval: 1.3-2.2) and any anxiety disorder (AOR: 1.8; 1.4-2.2), although not of substance use disorders (AOR: 1.2; 0.9-1.5). Conversely, Wave 1 major depressive episodes significantly increased risk of Wave 2 manic episodes (AOR: 2.2; 1.7-2.9) and anxiety disorders (AOR: 1.7; 1.5-2.0), although not substance use disorders (AOR: 1.0; 0.9-1.2). Adults with manic episodes have an approximately equivalent relative risk of developing depression episodes and anxiety disorders. Greater research and clinical focus is warranted on connections between manic episodes and anxiety disorders.

The epidemiology of common mental disorders from age 20 to 50: results from the prospective Zurich cohort Study.

BACKGROUND: There are only a small number of prospective studies that have systematically evaluated standardised diagnostic criteria for mental disorder for more than a decade. The aim of this study is to present the approximated overall and sex-specific cumulative incidence of mental disorder in the Zurich cohort study, a prospective cohort study of 18-19 years olds from the canton of Zurich, Switzerland, who were followed through age 50. METHOD: A stratified sample of 591 participants were interviewed with the Structured Psychopathological Interview and Rating of the Social Consequences of Psychological Disturbances for Epidemiology, a semi-structured interview that uses a bottom-up approach to assess the past-year presence of 15 psychiatric syndromes. Seven interview waves took place between 1979 and 2008. Approximated cumulative incidence was estimated using Kaplan-Meier methods. RESULTS: Rates of mental disorder were considerably higher than those generally reported in cross-sectional surveys. We found rates ranging from 32.5% for major depressive disorder to 1.2% for Bipolar I disorder. The cumulative probability of experiencing any of the mental disorders assessed by age 50 was 73.9%, the highest reported to date. We also found that rates differed by sex for most disorders, with females generally reporting higher rates of mood, anxiety and phobic disorder, and males reporting higher rates of substance- and alcohol-related disorders. CONCLUSIONS: These findings confirm those of other long-term prospective studies that indicate the nearly universal nature of disturbances of emotion and behaviour across the life span. Greater community awareness of the normative nature of these experiences is warranted. An important area of future research is study long-term course and stability to determine who among those with such disturbances suffer from chronic disabling mental disorders. Such longitudinal studies may aid in directing services and intervention efforts where they are most needed.

A population-based study of the risk of schizophrenia and bipolar disorder associated with parent-child separation during development.

BACKGROUND: There is growing interest in the role of childhood adversities, including parental death and separation, in the etiology of psychotic disorders. However, few studies have used prospectively collected data to specifically investigate parental separation across development, or assessed the importance of duration of separation, and family characteristics. METHOD: We measured three types of separation not due to death: maternal, paternal, and from both parents, across the ages of 1-15 years among a cohort of 985 058 individuals born in Denmark 1971-1991 and followed to 2011. Associations with narrowly and broadly defined schizophrenia and bipolar disorder in the psychiatric register were assessed in terms of separation occurrence, age of separation, and number of years separated. Interactions with parental history of mental disorder were assessed. RESULTS: Each type of separation was associated with all three outcomes, adjusting for age, sex, birth period, calendar year, family history of mental disorder, urbanicity at birth and parental age. Number of years of paternal separation was positively associated with both schizophrenia and bipolar disorder. Associations between separation from both parents and schizophrenia were stronger when separation occurred at later ages, while those with bipolar disorder remained stable across development. The first occurrence of paternal separation appeared to increase risk more when it occurred earlier in childhood. Associations differed according to parental history of mental disorder, although in no situation was separation protective. CONCLUSIONS: Effects of parental separation may differ by type, developmental timing and family characteristics. These findings highlight the importance of considering such factors in studies of childhood adversity.

The structured diagnostic interview for sleep patterns and disorders: rationale and initial evaluation.

OBJECTIVES: We aimed to describe and report the initial validity of a newly developed structured interview for sleep disorders (Diagnostic Interview for Sleep Patterns and Disorders [DISP]) administered by trained lay interviewers. METHODS: A total of 225 patients with various sleep disorders were recruited from two nationally recognized sleep centers in the United States. The International Classification of Sleep Disorders, second edition (ICSD-2) criteria, were used to classify sleep disorders (e.g., delayed sleep phase disorder, hypersomnia, narcolepsy with cataplexy [NC], restless legs syndrome [RLS], periodic limb movement disorder [PLMD], insomnia, rapid eye movement sleep behavior disorder [RBD], and obstructive sleep apnea [OSA]). Interview diagnoses were compared with final diagnoses by sleep specialists (reference diagnosis based on clinical history, examination, and polysomnography [PSG] when indicated). RESULTS: DISP diagnoses had fair to substantial concordance with clinician diagnoses for various sleep disorders, with area under the receiver operator characteristic curves (AUC) ranging from 0.65 to 0.84. Participants classified by the clinician as having a sleep disorder were moderately well-detected (sensitivity ranging from 0.50 for RBD disorder to 0.87 for insomnia). Substantial specificity (>0.8) also was seen for five of the eight sleep disorders (i.e., delayed sleep phase, hypersomnia, NC, PLMD, and RBD). Interviews were more likely than clinicians to detect disorders secondary to the primary sleep problem. CONCLUSIONS: The DISP provides an important tool for the detection of a wide range of sleep disorders in clinical settings and is particularly valuable in the detection of secondary disorders that were not the primary referral diagnosis.

Threshold and subthreshold generalized anxiety disorder among US adolescents: prevalence, sociodemographic, and clinical characteristics.

BACKGROUND: Threshold and subthreshold forms of generalized anxiety disorder (GAD) are highly prevalent and impairing conditions among adults. However, there are few general population studies that have examined these conditions during the early life course. The primary objectives of this study were to: (1) examine the prevalence, and sociodemographic and clinical characteristics of threshold and subthreshold forms of GAD in a nationally representative sample of US youth; and (2) test differences in sociodemographic and clinical characteristics between threshold and subthreshold forms of the disorder. METHOD: The National Comorbidity Survey-Adolescent Supplement is a nationally representative face-to-face survey of 10,123 adolescents 13 to 18 years of age in the continental USA. RESULTS: Approximately 3% of adolescents met criteria for threshold GAD. Reducing the required duration from 6 months to 3 months resulted in a 65.7% increase in prevalence (5.0%); further relaxing the uncontrollability criterion led to an additional 20.7% increase in prevalence (6.1%). Adolescents with all forms of GAD displayed a recurrent clinical course marked by substantial impairment and co-morbidity with other psychiatric disorders. There were few significant differences in sociodemographic and clinical characteristics between threshold and subthreshold cases of GAD. Results also revealed age-related differences in the associated symptoms and clinical course of GAD. CONCLUSIONS: Findings demonstrate the clinical significance of subthreshold forms of GAD among adolescent youth, highlighting the continuous nature of the GAD construct. Age-related differences in the associated symptoms and clinical course of GAD provide further support for criteria that capture variation in clinical features across development.

Specificity of psychosis, mania and major depression in a contemporary family study.

There has been increasing attention to the subgroups of mood disorders and their boundaries with other mental disorders, particularly psychoses. The goals of the present paper were (1) to assess the familial aggregation and co-aggregation patterns of the full spectrum of mood disorders (that is, bipolar, schizoaffective (SAF), major depression) based on contemporary diagnostic criteria; and (2) to evaluate the familial specificity of the major subgroups of mood disorders, including psychotic, manic and major depressive episodes (MDEs). The sample included 293 patients with a lifetime diagnosis of SAF disorder, bipolar disorder and major depressive disorder (MDD), 110 orthopedic controls, and 1734 adult first-degree relatives. The diagnostic assignment was based on all available information, including direct diagnostic interviews, family history reports and medical records. Our findings revealed specificity of the familial aggregation of psychosis (odds ratio (OR)=2.9, confidence interval (CI): 1.1-7.7), mania (OR=6.4, CI: 2.2-18.7) and MDEs (OR=2.0, CI: 1.5-2.7) but not hypomania (OR=1.3, CI: 0.5-3.6). There was no evidence for cross-transmission of mania and MDEs (OR=.7, CI:.5-1.1), psychosis and mania (OR=1.0, CI:.4-2.7) or psychosis and MDEs (OR=1.0, CI:.7-1.4). The strong familial specificity of psychotic, manic and MDEs in this largest controlled contemporary family study challenges the growing assertion that the major types of mood disorders are manifestations of a common underlying diathesis.

Independence of familial transmission of mania and depression: results of the NIMH family study of affective spectrum disorders.

The goal of this study is to investigate the familial transmission of the spectrum of bipolar disorder in a nonclinical sample of probands with a broad range of manifestations of mood disorders. The sample included a total of 447 probands recruited from a clinically enriched community screening and their 2082 adult living and deceased first-degree relatives. A best estimate diagnostic procedure that was based on either direct semistructured interview or structured family history information from multiple informants regarding non-interviewed relatives was employed. Results revealed that there was specificity of familial aggregation of bipolar I (BP I; odds ratio (OR)=8.40; 3.27-20.97; h2=0.83) and major depressive disorder (OR=2.26; 1.58-3.22; h2=0.20), but not BP II. The familial aggregation of BP I was primarily attributable to the familial specificity of manic episodes after adjusting for both proband and relative comorbid anxiety and substance use disorders. There was no significant cross-aggregation between mood disorder subtypes suggesting that the familial transmission of manic and major depressive episodes is independent despite the high magnitude of comorbidity between these mood states. These findings confirm those of earlier studies of the familial aggregation of bipolar disorder and major depression in the first nonclinical sample, and the largest family study of bipolar disorder in the USA using contemporary nonhierarchical diagnostic criteria for mood and anxiety disorders. The results suggest that these major components of bipolar disorder may represent distinct underlying pathways rather than increasingly severe manifestations of a common underlying diathesis. Therefore, dissection of the broad bipolar phenotype in genetic studies could actually generate new findings that could index novel biologic pathways underlying bipolar disorder.

Evidence for a differential role of HPA-axis function, inflammation and metabolic syndrome in melancholic versus atypical depression.

The hypothalamic-pituitary-adrenal (HPA) axis and the inflammatory response system have been suggested as pathophysiological mechanisms implicated in the etiology of major depressive disorder (MDD). Although meta-analyses do confirm associations between depression and these biological systems, effect sizes vary greatly among individual studies. A potentially important factor explaining variability is heterogeneity of MDD. Aim of this study was to evaluate the association between depressive subtypes (based on latent class analysis) and biological measures. Data from 776 persons from the Netherlands Study of Depression and Anxiety, including 111 chronic depressed persons with melancholic depression, 122 with atypical depression and 543 controls were analyzed. Inflammatory markers (C-reactive protein, interleukin-6, tumor necrosis factor-α), metabolic syndrome components, body mass index (BMI), saliva cortisol awakening curves (area under the curve with respect to the ground (AUCg) and with respect to the increase (AUCi)), and diurnal cortisol slope were compared among groups. Persons with melancholic depression had a higher AUCg and higher diurnal slope compared with persons with atypical depression and with controls. Persons with atypical depression had significantly higher levels of inflammatory markers, BMI, waist circumference and triglycerides, and lower high-density lipid cholesterol than persons with melancholic depression and controls. This study confirms that chronic forms of the two major subtypes of depression are associated with different biological correlates with inflammatory and metabolic dysregulation in atypical depression and HPA-axis hyperactivity in melancholic depression. The data provide further evidence that chronic forms of depressive subtypes differ not only in their symptom presentation, but also in their biological correlates. These findings have important implications for future research on pathophysiological pathways of depression and treatment.

Stability and transitions of depressive subtypes over a 2-year follow-up.

BACKGROUND: Identifying depressive subtypes is an important tool in reducing the heterogeneity of major depressive disorder. However, few studies have examined the stability of putative subtypes of depression over time. METHOD: The sample included 488 persons from the Netherlands Study of Depression and Anxiety (NESDA) who had major depressive disorder at baseline and at the 2-year follow-up assessment. A latent transition analysis (LTA) was applied to examine the stability of depressive subtypes across time-points. Differences in demographic, clinical, psychosocial and health correlates between subtypes were evaluated in a subsample of persons with stable subtypes. RESULTS: Three subtypes were identified at each time-point: a moderate subtype (prevalence T0 39%, T1 42%), a severe typical subtype (T0 30%, T1 25%), and a severe atypical subtype (T0 31%, T1 34%). The LTA showed 76% stability across the 2-year follow-up, with the greatest stability in the severe atypical class (79%). Analyses of correlates in the stable subtypes showed a predominance of women and more overweight and obesity in the severe atypical subtype, and a greater number of negative life events and higher neuroticism and functioning scores in the severe typical subtype. CONCLUSIONS: Subtypes of major depressive disorder were found to be stable across a 2-year follow-up and to have distinct determinants, supporting the notion that the identified subtypes are clinically meaningful.

Bipolar disorder with frequent mood episodes in the national comorbidity survey replication (NCS-R).

Virtually nothing is known about the epidemiology of rapid cycling bipolar disorder (BPD) in community samples. Nationally representative data are reported here for the prevalence and correlates of a surrogate measure of DSM-IV rapid cycling BPD from the National Comorbidity survey Replication (NCS-R), a national survey of the US household population. DSM-IV disorders were assessed in the NCS-R with the WHO Composite International Diagnostic Interview (CIDI). Although the CIDI did not assess rapid cycling, it did assess the broader category of 12-month BPD with frequent mood episodes (FMEs), having at least four episodes of mania/hypomania or major depression in the 12 months before interview. Roughly one-third of NCS-R respondents with lifetime DSM-IV BPD and half with 12-month BPD met criteria for FME. FME was associated with younger age-of-onset (of BP-I, but not BP-II) and higher annual persistence (73% of the years since first onset of illness with an episode) than non-FME BPD. No substantial associations of FME vs non-FME BPD were found with socio-demographics, childhood risk factors (parental mental disorders, other childhood adversities) or comorbid DSM-IV disorders. However, FME manic episodes had greater clinical severity than non-FME episodes (assessed with a fully structured version of the Young Mania Rating Scale) and FME hypomanic episodes had greater role impairment than non-FME episodes (assessed with the Sheehan Disability Scales). Whether these indicators of severity merely reflect attenuated effects of rapid cycling or independent effects of sub-threshold rapid cycling warrants further study given the high proportion of lifetime cases who met criteria for FME.

Substance use and behaviour disorders in Puerto Rican youth: a migrant family study.

BACKGROUND: Hispanics in the USA have higher rates of substance use disorders than similar ethnic groups residing in Latin American nations, and recent evidence suggests an increase in substance use among US Hispanic youth. This investigation examines the familial and societal correlates of this increase by comparing Puerto Rican families residing in the mainland USA and Puerto Rico. METHODS: Using migrant and controlled family study methods, 279 probands in San Juan and 236 probands in New Haven were recruited from treatment clinics and the general community to compose four diagnostic groups: drug abuse/dependence; alcohol abuse/dependence; psychiatric controls; unaffected controls. 806 biological offspring aged 12-17 were then directly interviewed. RESULTS: Total rates for alcohol use were greater among San Juan youth than their migrant counterparts. By contrast, US migrant adolescents were more likely to use cannabis. A strong association was observed between parental and child substance use at both sites, particularly for boys, and offspring of probands with drug use disorders were at greatest risk for substance use and related disorders. Familial aggregation patterns did not vary substantially by site. CONCLUSIONS: Despite societal influences on the magnitude and patterns of substance use in migrant youth, the consistent influence of parental disorders across sites reveals that the cross-generational transmission of substance use disorders in prior studies extends to Hispanic families and is an important factor to consider in the development of prevention strategies.

Mental disorders as risk factors for later substance dependence: estimates of optimal prevention and treatment benefits.

BACKGROUND: Although mental disorders have been shown to predict subsequent substance disorders, it is not known whether substance disorders could be cost-effectively prevented by large-scale interventions aimed at prior mental disorders. Although experimental intervention is the only way to resolve this uncertainty, a logically prior question is whether the associations of mental disorders with subsequent substance disorders are strong enough to justify mounting such an intervention. We investigated this question in this study using simulations to estimate the number of substance disorders that might be prevented under several hypothetical intervention scenarios focused on mental disorders. METHOD: Data came from the National Comorbidity Survey Replication (NCS-R), a nationally representative US household survey that retrospectively assessed lifetime history and age of onset of DSM-IV mental and substance disorders. Survival analysis using retrospective age-of-onset reports was used to estimate associations of mental disorders with subsequent substance dependence. Simulations based on the models estimated effect sizes in several hypothetical intervention scenarios. RESULTS: Although successful intervention aimed at mental disorders might prevent some proportion of substance dependence, the number of cases of mental disorder that would have to be treated to prevent a single case of substance dependence is estimated to be so high that this would not be a cost-effective way to prevent substance dependence (in the range 76-177 for anxiety-mood disorders and 40-47 for externalizing disorders). CONCLUSIONS: Treatment of prior mental disorders would not be a cost-effective way to prevent substance dependence. However, prevention of substance dependence might be considered an important secondary outcome of interventions for early-onset mental disorders.

Sex differences in the transmission of migraine.

Consistent evidence demonstrates that migraine is far more common in women than in men, but the explanations for this preponderance have not been systematically evaluated. We examined whether the female preponderance is attributable to genetic factors using data from a controlled family study which included 260 probands and their 1232 first-degree adult relatives. We found that although the risk of migraine was three times greater among the relatives of probands with migraine compared with controls, there was no differential risk of migraine among the relatives of male vs. female probands with migraine. Taking these data together with other family studies, we conclude that the increased risk of migraine in females is likely to result from increased exposure to non-familial endogenous or exogenous risk factors for migraine that lower the threshold for expression of migraine in women.

Genetic epidemiology of anxiety disorders.

This chapter reviews the genetic epidemiology of the major subtypes of anxiety disorders including panic disorder, phobic disorders, generalized anxiety disorder, and obsessive-compulsive disorder. Controlled family studies reveal that all of these anxiety subtypes are familial, and twin studies suggest that the familial aggregation is attributable in part to genetic factors. Panic disorder and, its spectrum have the strongest magnitude of familial clustering and genetic underpinnings. Studies of offspring of parents with anxiety disorders an increased risk of mood and anxiety disorders, but there is far less specificity of the manifestations of anxiety in children and young adolescents. Although there has been a plethora of studies designed to identify genes underlying these conditions, to date, no specific genetic loci have been identified and replicated in independent samples.

Family and high-risk studies of social anxiety disorder.

OBJECTIVE: To present data on the role of familial factors in the etiology of social anxiety disorder. METHOD: Findings presented from a family/high-risk study (the Yale Family Study) and a prospective community study of youth (the Munich Early Developmental Stages of Psychopathology (EDSP) Study). RESULTS: The Yale Family Study demonstrated a substantial degree of familial aggregation of social anxiety disorder and specificity with respect to other anxiety subtypes among adult relatives. The Yale high-risk component and the EDSP Study confirm the association between parental and offspring social anxiety, but did not yield consistent evidence for an association between familial environmental factors and social anxiety. CONCLUSION: Future studies are needed to examine mechanisms for the specificity of social anxiety disorder aggregation, to identify vulnerability factors for its development and to pinpoint environmental conditions that may enhance or suppress expression of underlying vulnerability.