Clara Hellner Gumpert

The Swedish Twin Registry: Establishment of a Biobank and Other Recent Developments

The Swedish Twin Registry (STR) today contains more than 194,000 twins and more than 75,000 pairs have zygosity determined by an intra-pair similarity algorithm, DNA, or by being of opposite sex. Of these, approximately 20,000, 25,000, and 30,000 pairs are monozygotic, same-sex dizygotic, and opposite-sex dizygotic pairs, respectively. Since its establishment in the late 1950s, the STR has been an important epidemiological resource for the study of genetic and environmental influences on a multitude of traits, behaviors, and diseases. Following large investments in the collection of biological specimens in the past 10 years we have now established a Swedish twin biobank with DNA from 45,000 twins and blood serum from 15,000 twins, which effectively has also transformed the registry into a powerful resource for molecular studies. We here describe the main projects within which the new collections of both biological samples as well as phenotypic measures have been collected. Coverage by year of birth, zygosity determination, ethnic heterogeneity, and influences of in vitro fertilization are also described.

Autistic-like traits and their association with mental health problems in two nationwide twin cohorts of children and adults.

BACKGROUND Autistic-like traits (ALTs), that is restrictions in intuitive social interaction, communication and flexibility of interests and behaviors, were studied in two population-based Swedish twin studies, one in children and one in adults: (1) to examine whether the variability in ALTs is a meaningful risk factor for concomitant attention deficit hyperactivity disorder (ADHD), anxiety, conduct problems, depression and substance abuse, and (2) to assess whether common genetic and environmental susceptibilities can help to explain co-existence of ALTs and traits associated with such concomitant problems. METHOD Two nationwide twin cohorts from Sweden (consisting of 11 222 children and 18 349 adults) were assessed by DSM-based symptom algorithms for autism. The twins were divided into six groups based on their degree of ALTs and the risk for concomitant mental health problems was calculated for each group. Genetic and environmental susceptibilities common to ALTs and the other problem types were examined using bivariate twin modeling. RESULTS In both cohorts, even the lowest degree of ALTs increased the risk for all other types of mental health problems, and these risk estimates increased monotonically with the number of ALTs. For all conditions, common genetic and environmental factors could be discerned. Overall, the phenotypic correlation between ALTs and the traits examined were less pronounced in adulthood than in childhood and less affected by genetic compared with environmental factors. CONCLUSIONS Even low-grade ALTs are relevant to clinical psychiatry as they increase the risk for several heterotypical mental health problems. The association is influenced partly by common genetic and environmental susceptibilities. Attention to co-existing ALTs is warranted in research on a wide range of mental disorders.

Children's Global Assessment Scale (CGAS) in a naturalistic clinical setting: Inter-rater reliability and comparison with expert ratings

The Childrens Global Assessment Scale (CGAS) is a tool to assess the overall level of functioning of children in Child and Adolescent Mental Health Services (CAMHS). Even though the use of this rating scale requires trained raters, it is commonly deployed without prior training in clinical settings. The aim of this study was to investigate the reliability and the agreement of CGAS ratings with an expert rating, in a clinical setting with untrained raters. Five experienced clinicians rated five vignettes to provide expert ratings. These vignettes were then rated by 703 health-care professionals representing 33 Swedish CAMHS. The health-care professionals rated the vignettes significantly higher (showing better global functioning) than the expert ratings. There was a wide range between the minimum and maximum ratings. The intraclass correlation coefficient was 0.73, which indicates moderate inter-rater reliability. Neither clinical experience nor earlier experience of using CGAS influenced the agreement with the expert ratings. The inter-rater reliability is moderate when CGAS is used in a clinical setting with untrained raters. Further, the untrained raters differed substantially from the experts. This stresses the importance of proper training in conjunction with the introduction of new rating scales.

Predictive properties of the A-TAC inventory when screening for childhood-onset neurodevelopmental problems in a population-based sample

BackgroundIdentifying children with childhood-onset neurodevelopmental problems (NDPs, defined here as autism spectrum disorders [ASDs], attention-deficit/hyperactivity disorder [AD/HD], tic disorders [TDs], learning disorders [LDs] and development coordination disorder), using easily administered screening instruments, is a prerequisite for epidemiological research. Such instruments are also clinically useful to prioritize children for comprehensive assessments, to screen risk groups, and to follow controls.Autism–Tics, ADHD, and other Co-morbidities inventory (A-TAC) was developed to meet these requirements; here the A-TAC’s prospective and psychometric properties are examined, when used in a population-based, epidemiological setting.MethodsSince 2004, parents of all Swedish twins have been asked to take part in an ongoing, nation-wide twin study (The Child and Adolescent Twin Study in Sweden). The study includes the A-TAC, carried out as a telephone interview with parents of twins aged 9 or 12. In the present study, screen-positive twins from three birth year cohorts (1993–1995) were invited to a comprehensive clinical follow-up (blinded for previous screening results) together with their co-twins and randomly selected, healthy controls at age 15 (Total N = 452).ResultsSensitivity and specificity of A-TAC scores for predicting later clinical diagnoses were good to excellent overall, with values of the area under the receiver operating characteristics curves ranging from 0.77 (AD/HD) to 0.91 (ASDs). Among children who were screen-positive for an ASD, 48% received a clinical diagnosis of ASDs. For AD/HD, the corresponding figure was also 48%, for LDs 16%, and for TDs 60%. Between 4% and 35% of screen-positive children did not receive any diagnosis at the clinical follow-up three years later. Among screen-negative controls, prevalence of ASDs, AD/HD, LDs, and TDs was 0%, 7%, 4%, and 2%, respectively.ConclusionsThe A–TAC appeared to be a valid instrument to assess NDPs in this population-based, longitudinal study. It has good-to-excellent psychometric properties, with an excellent ability to distinguish NDPs (mainly ASDs) from non-NDPs at least three years after the screening evaluations, although specific diagnoses did not correspond closely to actual clinical diagnoses.

Validation of the Alcohol Use Disorders Identification Test and the Drug Use Disorders Identification Test in a Swedish sample of suspected offenders with signs of mental health problems: Results from the Mental Disorder, Substance Abuse and Crime study

Substance abuse is common among offenders. One method widely used for the detection of substance abuse is screening. This study explored the concurrent validity of the Alcohol Use Disorders Identification Test (AUDIT) and the Drug Use Disorders Identification Test (DUDIT) screening tools in relation to (a) substance abuse and dependency diagnoses and (b) three problem severity domains of the sixth version of the Addiction Severity Index in a sample of 181 suspected offenders with signs of mental health problems. The screening tools showed moderate to high accuracy for identification of dependency diagnoses. The AUDIT was associated with alcohol problem severity, whereas the DUDIT was associated with drug and legal problem severity. Administering the screening tools in the current population yields valid results. However, the suggested cutoff scores should be applied with caution due to the discrepancy between present and previous findings.

Prevalence, Comorbidity and Heritability of Hoarding Symptoms in Adolescence: A Population Based Twin Study in 15-Year Olds

Background Hoarding Disorder (HD) is often assumed to be an ‘old age’ problem, but many individuals diagnosed with HD retrospectively report first experiencing symptoms in childhood or adolescence. We examined the prevalence, comorbidity and etiology of hoarding symptoms in adolescence. Methods To determine the presence of clinically significant hoarding symptoms, a population-based sample of 15-year old twins (N = 3,974) completed the Hoarding Rating Scale-Self Report. Co-occurring Obsessive Compulsive Disorder (OCD), Autism Spectrum Disorders (ASD) and Attention Deficit Hyperactivity Disorder (ADHD) were estimated from parental report. Model-fitting analyses divided hoarding symptom scores into additive genetic, shared, and non-shared environmental effects. Results The prevalence of clinically significant hoarding symptoms was 2% (95% CI 1.6–2.5%), with a significantly higher prevalence in girls than boys. Exclusion of the clutter criterion (as adolescents do not have control over their environment) increased the prevalence rate to 3.7% (95% CI 3.1–4.3%). Excessive acquisition was reported by 30–40% among those with clinically significant hoarding symptoms. The prevalence of co-occurring OCD (2.9%), ASD (2.9%) and ADHD (10.0%) was comparable in hoarding and non-hoarding teenagers. Model-fitting analyses suggested that, in boys, additive genetic (32%; 95% CI 13–44%) and non-shared environmental effects accounted for most of the variance. In contrast, among girls, shared and non-shared environmental effects explained most of the variance, while additive genetic factors played a negligible role. Conclusions Hoarding symptoms are relatively prevalent in adolescents, particularly in girls, and cause distress and/or impairment. Hoarding was rarely associated with other common neurodevelopmental disorders, supporting its DSM-5 status as an independent diagnosis. The relative importance of genetic and shared environmental factors for hoarding differed across sexes. The findings are suggestive of dynamic developmental genetic and environmental effects operating from adolescence onto adulthood.

Varenicline and risk of psychiatric conditions, suicidal behaviour, criminal offending, and transport accidents and offences: population based cohort study

Objective To examine associations between varenicline and the incidence of a range of adverse outcomes. Design Population based cohort study using within person analyses to control for confounding by indication. Setting Whole population of Sweden. Participants 7 917 436 people aged 15 and over, of whom 69 757 were treated with varenicline between 2006 and 2009. Main outcome measures Incidence of new psychiatric conditions, suicidal behaviour, suspected and convicted criminal offending, transport accidents, and suspected and convicted traffic offences. Results In the whole population, 337 393 new psychiatric conditions were diagnosed during follow-up. In addition, 507 823 suspected and 338 608 convicted crimes, 40 595 suicidal events, 124 445 transport accidents, and 99 895 suspected and 57 068 convicted traffic crimes were recorded. Within person analyses showed that varenicline was not associated with significant hazards of suicidal behaviour, criminal offending, transport accidents, traffic offences, or psychoses. However, varenicline was associated with a small increase in the risk of anxiety conditions (hazard ratio 1.23, 95% confidence interval 1.01 to 1.51) and mood conditions (1.31, 1.06 to 1.63), which was only seen in people with pre-existing psychiatric disorders. Conclusions Concerns that varenicline is associated with an increased risk of many adverse outcomes, including suicidality and accidents, are not supported in this observational study. The small increase in risk of two psychiatric conditions in people with pre-existing psychiatric disorders needs to be confirmed using other research designs.

Expert Testimony on Child Sexual Abuse:a Qualitative Study of the Swedish Approach toStatement Analysis

Statement analysis is an evaluation method occasionally used forassessing childrens testimony in cases of alleged sexual abuse. InSweden, statement analytical evaluations can be presented as expertevidence in legal proceedings. The purpose of the present study was toexplore the Swedish application of statement analysis, developed by Dr.Arne Trankell. Ten written expert witness reports were subjected to acombination of qualitative and quantitative content analysis. Inaddition to exploring what information was considered in theevaluations, the study focused on the way experts integrated data, andhow they interpreted the results of their evaluations. Statementanalysis in Sweden is characterised by a case-related approach, ascompared to the way of using pre-defined criteria within the frameworkof Statement Validity Analysis. Experts used statement characteristicsin different ways and emphasised different aspects of cases in order toreach their conclusions. Most experts used alternative hypotheses inorder to evaluate their data. Although the use of hypothesis-testing hasstrong support in the literature, there appeared to be risks for logicalmistakes connected to the conveyance of tentative hypotheses intoconclusions. The results are discussed in relation to other applicationsof statement analysis.

Selective serotonin reuptake inhibitors and violent crime: a cohort study

Background Although selective serotonin reuptake inhibitors (SSRIs) are widely prescribed, associations with violence are uncertain. Methods and Findings From Swedish national registers we extracted information on 856,493 individuals who were prescribed SSRIs, and subsequent violent crimes during 2006 through 2009. We used stratified Cox regression analyses to compare the rate of violent crime while individuals were prescribed these medications with the rate in the same individuals while not receiving medication. Adjustments were made for other psychotropic medications. Information on all medications was extracted from the Swedish Prescribed Drug Register, with complete national data on all dispensed medications. Information on violent crime convictions was extracted from the Swedish national crime register. Using within-individual models, there was an overall association between SSRIs and violent crime convictions (hazard ratio [HR] = 1.19, 95% CI 1.08–1.32, p < 0.001, absolute risk = 1.0%). With age stratification, there was a significant association between SSRIs and violent crime convictions for individuals aged 15 to 24 y (HR = 1.43, 95% CI 1.19–1.73, p < 0.001, absolute risk = 3.0%). However, there were no significant associations in those aged 25–34 y (HR = 1.20, 95% CI 0.95–1.52, p = 0.125, absolute risk = 1.6%), in those aged 35–44 y (HR = 1.06, 95% CI 0.83–1.35, p = 0.666, absolute risk = 1.2%), or in those aged 45 y or older (HR = 1.07, 95% CI 0.84–1.35, p = 0.594, absolute risk = 0.3%). Associations in those aged 15 to 24 y were also found for violent crime arrests with preliminary investigations (HR = 1.28, 95% CI 1.16–1.41, p < 0.001), non-violent crime convictions (HR = 1.22, 95% CI 1.10–1.34, p < 0.001), non-violent crime arrests (HR = 1.13, 95% CI 1.07–1.20, p < 0.001), non-fatal injuries from accidents (HR = 1.29, 95% CI 1.22–1.36, p < 0.001), and emergency inpatient or outpatient treatment for alcohol intoxication or misuse (HR = 1.98, 95% CI 1.76–2.21, p < 0.001). With age and sex stratification, there was a significant association between SSRIs and violent crime convictions for males aged 15 to 24 y (HR = 1.40, 95% CI 1.13–1.73, p = 0.002) and females aged 15 to 24 y (HR = 1.75, 95% CI 1.08–2.84, p = 0.023). However, there were no significant associations in those aged 25 y or older. One important limitation is that we were unable to fully account for time-varying factors. Conclusions The association between SSRIs and violent crime convictions and violent crime arrests varied by age group. The increased risk we found in young people needs validation in other studies.

RELIABILITY OF AUTISM-TICS, AD/HD, AND OTHER COMORBIDITIES (A-TAC) INVENTORY IN A TEST-RETEST DESIGN

The Autism-Tics, AD/HD, and other Comorbidities (A–TAC) inventory is used in epidemiological research to assess neurodevelopmental problems and coexisting conditions. Although the A–TAC has been applied in various populations, data on retest reliability are limited. The objective of the present study was to present additional reliability data. The A–TAC was administered by lay assessors and was completed on two occasions by parents of 400 individual twins, with an average interval of 70 days between test sessions. Intra- and inter-rater reliability were analysed with intraclass correlations and Cohens κ. A–TAC showed excellent test-retest intraclass correlations for both autism spectrum disorder and attention deficit hyperactivity disorder (each at .84). Most modules in the A–TAC had intra- and inter-rater reliability intraclass correlation coefficients of ≥ .60. Cohens κ indicated acceptable reliability. The current study provides statistical evidence that the A–TAC yields good test-retest reliability in a population-based cohort of children.