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Intellectual disability (ID) is associated with violent and sexual offending and victimization, but the importance of neuropsychiatric comorbidity and severity of disability remains unclear.
Methods
In a register-based cohort study of people born in Sweden 1980–1991 (n = 1 232 564), we investigated associations of mild and moderate/severe ID with any, violent and sexual crimes, and with assault victimization, stratified by comorbid autism and attention deficit hyperactivity disorder (ADHD). We defined ID by attendance at a special school or registered diagnosis and obtained data on criminal convictions and injuries or deaths due to assaults from nationwide registers until end of 2013.
Results
Compared to people without ID, autism or ADHD, men and women with mild or moderate/severe ID and comorbid ADHD had elevated risks of violent crimes [range of hazard ratios (HRs) 4.4–10.4] and assault victimization (HRs 2.0–7.7). Women with mild ID without comorbidities or with comorbid autism also had elevated risks of violent crimes and victimization (HRs 1.8–4.6) compared to women without ID, autism or ADHD. The relative risks of sexual offending and victimization were elevated in men and women with ID without comorbidities (HRs 2.6–12.7). The highest risks for sexual offending in men (HRs 9.4–11.0) and for sexual assault victimization in women (HRs 11.0–17.1) related to ID and comorbid ADHD.
Conclusions
The elevated risk of violent offending and assault victimization in people with ID is largely explained by comorbid ADHD, whereas ID is independently associated with sexual crimes and victimization, even though absolute risks are low.
Previous research has indicated that attention-deficit/hyperactivity disorder (ADHD) is associated with an increased risk for dementia, but studies are scarce and inconclusive. We aimed to investigate the association between ADHD, and dementia and mild cognitive impairment (MCI). Additionally, we aimed to investigate the impact of comorbid conditions, educational attainment, head injuries, other developmental disorders, and sex on the association.
Methods
The study population consisted of 3,591,689 individuals born between 1932 and 1963, identified from Swedish population-based registers. Cases of ADHD, dementia and MCI were defined according to ICD diagnostic codes and ATC codes for medication prescriptions. A Cox proportional hazards model was used to test the associations between ADHD, and dementia and MCI.
Results
Individuals with ADHD had an increased risk for dementia and MCI. After adjusting for sex and birth year, a hazard ratio (HR) was 2.92 (95% confidence interval 2.40–3.57) for dementia, and 6.21 (5.25–7.35) for MCI. Additional adjustment for psychiatric disorders (depression, anxiety, substance use disorder, and bipolar disorder) substantially attenuated the associations, HR = 1.62 (1.32–1.98) for dementia, and 2.54 (2.14–3.01) for MCI. Common metabolic disorders (hypertension, type 2 diabetes, and obesity), sleep disorders, head injuries, educational attainment, and other developmental disorders, had a limited impact on the association. The association between ADHD and dementia was stronger in men.
Conclusions
ADHD is a potential risk factor for dementia and MCI, although the risk significantly attenuates after controlling for psychiatric disorders. Further research is needed to confirm these findings and to explore underlying mechanisms of the associations.
Cesarean delivery (CD) has been associated with postpartum psychiatric disorders, but less is known about the risk of suicidal behaviors. We estimated the incidence and risk of suicide attempts and deaths during the first postpartum year in mothers who delivered via CD v. vaginally.
Method
All deliveries in Sweden between 1973 and 2012 were identified. The mothers were followed since delivery for 12 months or until the date of one of the outcomes (i.e. suicide attempt or death by suicide), death by other causes or emigration. Associations were estimated using Cox proportional hazards regression models.
Results
Of 4 016 789 identified deliveries, 514 113 (12.8%) were CDs and 3 502 676 (87.2%) were vaginal deliveries. During the 12-month follow-up, 504 (0.098%) suicide attempts were observed in the CD group and 2240 (0.064%) in the vaginal delivery group (risk difference: 0.034%), while 11 (0.0037%) deaths by suicide were registered in the CD group and 109 (0.0029%) in the vaginal delivery group (risk difference: 0.008%). Compared to vaginal delivery, CD was associated with an increased risk of suicide attempts [hazard ratio (HR) 1.46; 95% CI 1.32–1.60], but not of deaths by suicide (HR 1.44; 95% CI 0.88–2.36).
Conclusions
Maternal suicidal behaviors during the first postpartum year were uncommon in Sweden. Compared to vaginal delivery, CD was associated with a small increased risk of suicide attempts, but not death by suicide. Improved understanding of the association between CD and maternal suicidal behaviors may promote more appropriate measures to improve maternal mental well-being and further reduce suicidal risks.
Neurodevelopmental disorders (NDs) are associated with experiences of victimization, but mechanisms remain unclear. We explored sex differences and the role of familial factors and externalizing problems in the association between several NDs and violent victimization in adolescence and young adulthood.
Methods
Individuals born in Sweden 1985–1997, residing in Sweden at their 15th birthday, were followed until date of violent victimization causing a hospital visit or death, death due to other causes, emigration, or December 31, 2013, whichever came first. The exposures were diagnoses of attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), intellectual disability (ID) and other NDs. We used three different Cox regression models: a crude model, a model adjusted for familial confounding using sibling-comparisons, and a model additionally adjusted for externalizing problems.
Results
Among 1 344 944 individuals followed, on average, for 5 years, 74 487 were diagnosed with NDs and 37 765 had a hospital visit or died due to violence. ADHD was associated with an increased risk of violent victimization in males [hazard ratio (HR) 2.56; 95% confidence interval (CI) 2.43–2.70) and females (HR 5.39; 95% CI 4.97–5.85). ASD and ID were associated with an increased risk of violent victimization in females only. After adjusting for familial factors and externalizing problems, only ADHD was associated with violent victimization among males (HR 1.27; 95% CI 1.06–1.51) and females (HR 1.69; 95% CI 1.21–2.36).
Conclusions
Females with NDs and males with ADHD are at greater risk of being victim of severe violence during adolescence and young adulthood. Relevant mechanisms include shared familial liability and externalizing problems. ADHD may be independently associated with violent victimization.
Familial co-aggregation studies of eating disorders (EDs) and schizophrenia reveal shared genetic and environment factors, yet their etiological and clinical relationship remains unclear. We evaluate the influence of schizophrenia family history on clinical outcomes of EDs.
Methods
We conducted a cohort evaluation of the association between family history of schizophrenia and ED clinical features, psychiatric comorbidities, and somatic and mental health burden in individuals born in Sweden 1977–2003 with anorexia nervosa (AN) or other EDs (OED: bulimia nervosa, binge-eating disorder, and ED not otherwise specified).
Results
Of 12 424 individuals with AN and 20 716 individuals with OED, 599 (4.8%) and 1118 (5.4%), respectively, had a family history of schizophrenia (in up to third-degree relatives). Among individuals with AN, schizophrenia in first-degree relatives was significantly associated with increased comorbid attention-deficit/hyperactivity disorder (ADHD) [HR(95% CI) 2.26 (1.27–3.99)], substance abuse disorder (SUD) [HR (95% CI) 1.93 (1.25–2.98)], and anxiety disorders [HR (95% CI) 1.47 (1.08–2.01)], but higher lowest illness-associated body mass index (BMI) [1.14 kg/m2, 95% CI (0.19–2.10)]. Schizophrenia in any relative (up to third-degree) in AN was significantly associated with higher somatic and mental health burden, but lower ED psychopathology scores [−0.29, 95% CI (−0.54 to −0.04)]. Schizophrenia in first-degree relatives in individuals with OED was significantly associated with increased comorbid ADHD, obsessive-compulsive disorder, SUD, anxiety disorders, somatic and mental health burden, and suicide attempts.
Conclusions
We observed different patterns of ED-related outcomes, psychiatric comorbidity, and illness burden in individuals with EDs with and without family histories of schizophrenia and provide new insights into the diverse manifestations of EDs.
Previous research indicates that body dysmorphic disorder (BDD) is associated with risk of suicidality. However, studies have relied on small and/or specialist samples and largely focussed on adults, despite these difficulties commonly emerging in youth. Furthermore, the aetiology of the relationship remains unknown.
Methods
Two independent twin samples were identified through the Child and Adolescent Twin Study in Sweden, at ages 18 (N = 6027) and 24 (N = 3454). Participants completed a self-report measure of BDD symptom severity. Young people and parents completed items assessing suicidal ideation/behaviours. Logistic regression models tested the association of suicidality outcomes with: (a) probable BDD, classified using an empirically derived cut-off; and (b) continuous scores of BDD symptoms. Bivariate genetic models examined the aetiology of the association between BDD symptoms and suicidality at both ages.
Results
Suicidal ideation and behaviours were common among those with probable BDD at both ages. BDD symptoms, measured continuously, were linked with all aspects of suicidality, and associations generally remained significant after adjusting for depressive and anxiety symptoms. Genetic factors accounted for most of the covariance between BDD symptoms and suicidality (72.9 and 77.7% at ages 18 and 24, respectively), but with significant non-shared environmental influences (27.1 and 22.3% at ages 18 and 24, respectively).
Conclusions
BDD symptoms are associated with a substantial risk of suicidal ideation and behaviours in late adolescence and early adulthood. This relationship is largely explained by common genetic liability, but non-shared environmental effects are also significant and could provide opportunities for prevention among those at high-risk.
Although attention-deficit hyperactivity disorder (ADHD) is classified as a neurodevelopmental disorder in the latest diagnostic manuals, it shows phenotypic and genetic associations of similar magnitudes across neurodevelopmental, externalising and internalising disorders.
Aims
To investigate if ADHD is aetiologically more closely related to neurodevelopmental than externalising or internalising disorder clusters, after accounting for a general psychopathology factor.
Method
Full and maternal half-sibling pairs (N = 774 416), born between 1980 and 1995, were identified from the Swedish Medical Birth and Multi-Generation Registers, and ICD diagnoses were obtained from the Swedish National Patient Register. A higher-order confirmatory factor analytic model was fitted to examine associations between ADHD and a general psychopathology factor, as well as a neurodevelopmental, externalising and internalising subfactor. Quantitative genetic modelling was performed to estimate the extent to which genetic, shared and non-shared environmental effects influenced the associations with ADHD.
Results
ADHD was significantly and strongly associated with all three factors (r = 0.67–0.75). However, after controlling for a general psychopathology factor, only the association between ADHD and the neurodevelopmental-specific factor remained moderately strong (r = 0.43, 95% CI = 0.42–0.45) and was almost entirely influenced by genetic effects. In contrast, the association between ADHD and the externalising-specific factor was smaller (r = 0.25, 95% CI = 0.24–0.27), and largely influenced by non-shared environmental effects. There remained no internalising-specific factor after accounting for a general factor.
Conclusions
Findings suggest that ADHD comorbidity is largely explained by genetically influenced general psychopathology, but the strong link between ADHD and other neurodevelopmental disorders is also substantially driven by unique genetic influences.
Genetically informed studies have provided mixed findings as to what extent parental substance misuse is associated with offspring substance misuse and antisocial behavior due to shared environmental and genetic factors.
Methods
We linked data from nationwide registries for a cohort of 2 476 198 offspring born in Sweden 1958–1995 and their parents. Substance misuse was defined as International Classification of Diseases diagnoses of alcohol/drug use disorders or alcohol/drug-related criminal convictions. Quantitative genetic offspring-of-siblings analyses in offspring of monozygotic and dizygotic twin, full-sibling, and half-sibling parents were conducted.
Results
Both maternal and paternal substance misuse were robustly associated with offspring substance misuse [maternal adjusted hazard ratio (aHR) = 1.83 (95% confidence interval (CI) 1.80–1.87); paternal aHR = 1.96 (1.94–1.98)] and criminal convictions [maternal aHR = 1.56 (1.54–1.58); paternal aHR = 1.66 (1.64–1.67)]. Additive genetic effects explained 42% (95% CI 25–56%) and 46% (36–55%) of the variance in maternal and paternal substance misuse, respectively, and between 36 and 44% of the variance in substance misuse and criminality in offspring. The associations between parental substance misuse and offspring outcomes were mostly due to additive genetic effects, which explained 54–85% of the parent-offspring covariance. However, both nuclear and extended family environmental factors also contributed to the associations, especially with offspring substance misuse.
Conclusions
Our findings from a large offspring-of-siblings study indicate that shared genetic influences mostly explain the associations between parental substance misuse and both offspring substance misuse and criminality, but we also found evidence for the contribution of environmental factors shared by members of nuclear and extended families.
Many psychiatric disorders show gender differences in prevalence. Recent studies suggest that female patients diagnosed with anxiety and depression carry more genetic risks related to attention-deficit hyperactivity disorder (ADHD) compared with affected males.
Aims
In this register-based study, we aimed to test whether female patients who received clinical diagnoses of anxiety, depressive, bipolar and eating disorders are at higher familial risk for ADHD and other neurodevelopmental disorders, compared with diagnosed male patients.
Method
We analysed data from a record-linkage of several Swedish national registers, including 151 025 sibling pairs from 103 941 unique index individuals diagnosed with anxiety, depressive, bipolar or eating disorders, as well as data from 646 948 cousin pairs. We compared the likelihood of having a relative diagnosed with ADHD/neurodevelopmental disorders in index males and females.
Results
Female patients with anxiety disorders were more likely than affected males to have a brother with ADHD (odd ratio (OR) = 1.13, 95% CI 1.05–1.22). Results for broader neurodevelopmental disorders were similar and were driven by ADHD diagnoses. Follow-up analyses revealed similar point estimates for several categories of anxiety disorders, with the strongest effect observed for agoraphobia (OR = 1.64, 95% CI 1.12–2.39). No significant associations were found in individuals with depressive, bipolar or eating disorders, or in cousins.
Conclusions
These results provide modest support for the possibility that familial/genetic risks for ADHD may show gender-specific phenotypic expression. Alternatively, there could be gender-specific biases in diagnoses of anxiety and ADHD. These factors could play a small role in the observed gender differences in prevalence of ADHD and anxiety.
Quantitative genetic research includes a range of genetically sensitive research designs that rely on family samples to study the relative importance of genes and environments for individual difference in psychopathology. The past decades have seen an increase in quantitative genetic research focused on the origins of childhood and adolescent psychopathology. Evidence from this research univocally demonstrates that genetic factors play an important role in all forms of psychopathology, and that these genetic factors interact with the environment to shape the development of childhood and adolescent psychopathology. The goal of this chapter is to highlight how recent methodological developments and the accumulation of longitudinal data now allow quantitative genetic research to go beyond asking “if” genetic factors are important, to instead address important questions regarding gene-environment interplay in the development of childhood and adolescent psychopathology. It begins by introducing the family, adoption, and twin designs, and summarizing the main findings from these methods for child and adolescent psychopathology. It then provides concrete examples of how multivariate and longitudinal quantitative genetic research designs can be used to address important questions regarding etiology across different levels of symptom severity, comorbidity, and development, and to study gene-environment interplay in child and adolescent psychopathology. It concludes by highlighting important outstanding questions in childhood psychopathology that need to be addressed in future quantitative genetic research.
Social anxiety disorder (SAD) has been linked to academic underachievement, but previous studies had methodological limitations. We investigated the association between SAD and objective indicators of educational performance, controlling for a number of covariates and unmeasured confounders shared between siblings.
Methods
This population-based birth cohort study included 2 238 837 individuals born in Sweden between 1973 and 1997, followed-up until 2013. Within the cohort, 15 755 individuals had a recorded ICD-10 diagnosis of SAD in the Swedish National Patient Register. Logistic regression models tested the association between SAD and educational performance. We also identified 6488 families with full siblings discordant for SAD.
Results
Compared to unexposed individuals, individuals diagnosed with SAD were less likely to pass all subjects in the last year of compulsory education [adjusted odds ratios (aOR) ranging from 0.19 to 0.44] and less likely to be eligible for a vocational or academic programme in upper secondary education [aOR = 0.31 (95% confidence interval [CI] 0.30–0.33) and aOR = 0.52 (95% CI 0.50–0.55), respectively], finish upper secondary education [aOR = 0.19 (95% CI 0.19–0.20)], start a university degree [aOR = 0.47 (95% CI 0.45–0.49)], obtain a university degree [aOR = 0.35 (95% CI 0.33–0.37)], and finish postgraduate education [aOR = 0.58 (95% CI 0.43–0.80)]. Results were attenuated but remained statistically significant in adjusted sibling comparison models. When psychiatric comorbidities were taken into account, the results were largely unchanged.
Conclusions
Treatment-seeking individuals with SAD have substantially impaired academic performance throughout the formative years. Early detection and intervention are warranted to minimise the long-term socioeconomic impact of the disorder.
Anorexia nervosa and bulimia nervosa are two severe eating disorders associated with high premature mortality, suicidal risk and serious medical complications. Transition between anorexia nervosa and bulimia nervosa over the illness course and familial co-aggregation of the two eating disorders imply aetiological overlap. However, genetic and environmental liabilities to the overlap are poorly understood. Quantitative genetic research using clinical diagnosis is needed.
Methods
We acquired a clinical diagnosis of anorexia nervosa (prevalence = 0.90%) and bulimia nervosa (prevalence = 0.48%) in a large population-based sample (N = 782 938) of randomly selected full-sisters and maternal half-sisters born in Sweden between 1970 and 2005. Structural equation modelling was applied to quantify heritability of clinically diagnosed anorexia nervosa and bulimia nervosa and the contributions of genetic and environmental effects on their overlap.
Results
The heritability of clinically diagnosed anorexia nervosa and bulimia nervosa was estimated at 43% [95% confidence interval (CI) (36–50%)] and 41% (31–52%), respectively, in the study population, with the remaining variance explained by variance in unique environmental effects. We found statistically significant genetic [0.66, 95% CI (0.49–0.82)] and unique environmental correlations [0.55 (0.43–0.66)] between the two clinically diagnosed eating disorders; and their overlap was about equally explained by genetic and unique environmental effects [co-heritability 47% (35–58%)].
Conclusions
Our study supports shared mechanisms for anorexia nervosa and bulimia nervosa and extends the literature from self-reported behavioural measures to clinical diagnosis. The findings encourage future molecular genetic research on both eating disorders and emphasize clinical vigilance for symptom fluctuation between them.
Poor response to dopaminergic antipsychotics constitutes a major challenge in the treatment of psychotic disorders and markers for non-response during first-episode are warranted. Previous studies have found increased levels of glutamate and γ-aminobutyric acid (GABA) in non-responding first-episode patients compared to responders, but it is unknown if non-responders can be identified using reference levels from healthy controls (HCs).
Methods
Thirty-nine antipsychotic-naïve patients with first-episode psychosis and 36 matched HCs underwent repeated assessments with the Positive and Negative Syndrome Scale and 3T magnetic resonance spectroscopy. Glutamate scaled to total creatine (/Cr) was measured in the anterior cingulate cortex (ACC) and left thalamus, and levels of GABA/Cr were measured in ACC. After 6 weeks, we re-examined 32 patients on aripiprazole monotherapy and 35 HCs, and after 26 weeks we re-examined 30 patients on naturalistic antipsychotic treatment and 32 HCs. The Andreasen criteria defined non-response.
Results
Before treatment, thalamic glutamate/Cr was higher in the whole group of patients but levels normalized after treatment. ACC levels of glutamate/Cr and GABA/Cr were lower at all assessments and unaffected by treatment. When compared with HCs, non-responders at week 6 (19 patients) and week 26 (16 patients) had higher baseline glutamate/Cr in the thalamus. Moreover, non-responders at 26 weeks had lower baseline GABA/Cr in ACC. Baseline levels in responders and HCs did not differ.
Conclusion
Glutamatergic and GABAergic abnormalities in antipsychotic-naïve patients appear driven by non-responders to antipsychotic treatment. If replicated, normative reference levels for glutamate and GABA may aid estimation of clinical prognosis in first-episode psychosis patients.
Causes of the comorbidity of substance misuse with anxiety-related and depressive disorders (anxiety/depression) remain poorly known. We estimated associations of substance misuse and anxiety/depression in the general population and tested them while accounting for genetic and shared environmental factors.
Methods
We studied individuals born in Sweden 1968–1997 (n = 2 996 398) with follow-up in nationwide register data for 1997–2013. To account for familial effects, stratified analyses were conducted within siblings and twin pairs. Substance misuse was defined as ICD-10 alcohol or drug use disorder or an alcohol/drug-related criminal conviction. Three dimensions of ICD-10 anxiety and depressive disorders and a substance misuse dimension were identified through exploratory factor analysis.
Results
Substance misuse was associated with a 4.5-fold (95% CI 4.50–4.58) elevated risk of lifetime generalized anxiety/depression, 4.7-fold (95% CI 4.63–4.82) elevated risk of panic disorder and agora/social phobia, and 2.9-fold elevated risk of phobias/OCD (95% CI 2.82–3.02) as compared to those without substance misuse. The associations were attenuated in within-family analyses but we found elevated risks in monozygotic twin pairs discordant for substance misuse as well as significant non-shared environmental correlations. The association between anxiety/depression and substance misuse was mainly driven by generalized anxiety/depression, whereas other anxiety/depression dimensions had minor or no independent associations with substance misuse.
Conclusions
Substance misuse and anxiety/depression are associated at the population level, and these associations are partially explained by familial liabilities. Our findings indicate a common genetic etiology but are also compatible with a potential partially causal relationship between substance misuse and anxiety/depression.
Maternal polycystic ovary syndrome (PCOS) has been proposed as a model for investigating the role of prenatal androgen exposure in the development of neuropsychiatric disorders. However, women with PCOS are at higher risk of developing psychiatric conditions and previous studies are likely confounded by genetic influences.
Methods
A Swedish nationwide register-based cohort study was conducted to disentangle the influence of prenatal androgen exposure from familial confounding in the association between maternal PCOS and offspring attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorders (ASD), and Tourette's disorder and chronic tic disorders (TD/CTD). PCOS-exposed offspring (n = 21 280) were compared with unrelated PCOS-unexposed offspring (n = 200 816) and PCOS-unexposed cousins (n = 17 295). Associations were estimated with stratified Cox regression models.
Results
PCOS-exposed offspring had increased risk of being diagnosed with ADHD, ASD, and TD/CTD compared with unrelated PCOS-unexposed offspring. Associations were stronger in girls for ADHD and ASD but not TD/CTD [ADHD: adjusted hazard ratio (aHR) = 1.61 (95% confidence interval (CI) 1.31–1.99), ASD: aHR = 2.02 (95% CI 1.45–2.82)] than boys [ADHD: aHR = 1.37 (95% CI 1.19–1.57), ASD: aHR = 1.46 (95% CI 1.21–1.76)]. For ADHD and ASD, aHRs for girls were stronger when compared with PCOS-unexposed cousins, but slightly attenuated for boys.
Conclusions
Estimates were similar when accounting for familial confounding (i.e. genetics and environmental factors shared by cousins) and stronger in girls for ADHD and ASD, potentially indicating a differential influence of prenatal androgen exposure v. genetic factors. These results strengthen evidence for a potential causal influence of prenatal androgen exposure on the development of male-predominant neuropsychiatric disorders in female offspring of women with PCOS.
A recent family study of young adult males suggests a shared familial liability between attention-deficit/hyperactivity disorder (ADHD) and high body mass index (BMI), and a genome-wide meta-analysis reported a genetic correlation of 0.26 between ADHD and BMI. To date, it is unclear whether these findings generalize to the relationship between ADHD and clinically diagnosed obesity.
Method
By linking the Swedish national registers, we identified 25 38 127 individuals born between 1973 and 2000, together with their siblings and cousins. The risk of clinical obesity in individuals with ADHD was compared with the risk in those without ADHD. The relative contributions of genetic and environmental factors to the association between ADHD and clinical obesity were examined via assessment of the familial co-aggregation of the two conditions and quantitative genetic analysis.
Results
Individuals with ADHD were at an increased risk of clinical obesity compared with those without (risk difference 3.73%, 95% confidence interval (CI) 3.55–3.90%; risk ratio 3.05, 95% CI 2.95–3.15). Familial co-aggregation of ADHD and clinical obesity was detected and the strength of the co-aggregation decreased by decreasing genetic relatedness. The correlation between the liabilities to ADHD and clinical obesity can be entirely attributed to their genetic correlation (rg 0.30, 95% CI 0.17–0.44).
Conclusion
The association between ADHD and clinical obesity in adolescence and young adulthood can be entirely attributed to genetic underpinnings shared by the two conditions. Children with ADHD should be monitored for weight gain so that preventive measures can be taken for those on a suboptimal trajectory.
Traits of attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) are strongly associated in children and adolescents, largely due to genetic factors. Less is known about the phenotypic and aetiological overlap between ADHD and ASD traits in adults.
Methods
We studied 6866 individuals aged 20–28 years from the Swedish Study of Young Adult Twins. Inattention (IA) and hyperactivity/impulsivity (HI) were assessed using the WHO Adult ADHD Self-Report Scale-V1.1. Repetitive and restricted behaviours (RRB) and social interaction and communication (SIC) were assessed using the Autism-Tics, ADHD, and other Comorbidities inventory. We used structural equation modelling to decompose covariance between these ADHD and ASD trait dimensions into genetic and shared/non-shared environmental components.
Results
At the phenotypic level, IA was similarly correlated with RRB (r = 0.33; 95% Confidence Interval (CI) 0.31–0.36) and with SIC (r = 0.32; 95% CI 0.29–0.34), whereas HI was more strongly associated with RRB (r = 0.38; 95% CI 0.35–0.40) than with SIC (r = 0.24; 95% CI 0.21–0.26). Genetic and non-shared environmental effects accounted for similar proportions of the phenotypic correlations, whereas shared environmental effects were of minimal importance. The highest genetic correlation was between HI and RRB (r = 0.56; 95% 0.46–0.65), and the lowest was between HI and SIC (r = 0.33; 95% CI 0.23–0.43).
Conclusions
We found evidence for dimension-specific phenotypic and aetiological overlap between ADHD and ASD traits in adults. Future studies investigating mechanisms underlying comorbidity between ADHD and ASD may benefit from exploring several symptom-dimensions, rather than considering only broad diagnostic categories.
Transition across eating disorder diagnoses is common, reflecting instability of specific eating disorder presentations. Previous studies have examined temporal stability of diagnoses in adult treatment-seeking samples but have not uniformly captured initial presentation for treatment. The current study examines transitions across eating disorder diagnostic categories in a large, treatment-seeking sample of individuals born in Sweden and compares these transitions across two birth cohorts and from initial diagnosis.
Methods
Data from Swedish eating disorders quality registers were extracted in 2013, including 9622 individuals who were seen at least twice from 1999 to 2013. Patterns of remission were examined in the entire sample and subsequently compared across initial diagnoses. An older (born prior to 1990) and younger birth cohort were also identified, and analyses compared these cohorts on patterns of diagnostic transition.
Results
Although diagnostic instability was common, transition between threshold eating disorder diagnoses was infrequent. For all diagnoses, transition to remission was likely to occur following a diagnosis state that matched initial diagnosis, or through a subthreshold diagnostic state. Individuals in the younger cohort were more likely to transition to a state of remission than those in the older cohort.
Conclusions
Results indicate more temporal continuity in eating disorder presentations than suggested by previous research and highlight the importance of early detection and intervention in achieving remission.
Criminal offending is strongly transmitted across generations.
Aims
To clarify the contribution of rearing environment to cross-generational transmission of crime.
Method
Using Swedish national registries, we identified 1176 full-sibling and 3085 half-sibling sets from high-risk families where at least one sibling was adopted and the other raised by the biological parents.
Results
Risk for criminal conviction was substantially lower in the full- and half-siblings who were adopted v. home-reared (hazard ratios (HR) = 0.56, 95% CI 0.50–0.64 and 0.60, 95% CI 0.56–0.65, respectively). The protective effect of adoption was significantly stronger in sibships with two v. one high-risk parent.
Conclusions
Using matched high-risk full- and half-siblings, we found replicated evidence that (a) rearing environment has a strong impact on risk for criminal conviction, (b) high-quality rearing environments have especially strong effects in those at high familial risk for criminal offending and (c) the protective effects of adoption are stronger for more severe crimes and for repeated offending.
Mortality has been suggested to be increased in autism spectrum disorder
(ASD).
Aims
To examine both all-cause and cause-specific mortality in ASD, as well as
investigate moderating role of gender and intellectual ability.
Method
Odds ratios (ORs) were calculated for a population-based cohort of ASD
probands (n = 27 122, diagnosed between 1987 and 2009)
compared with gender-, age- and county of residence-matched controls
(n = 2 672 185).
Results
During the observed period, 24 358 (0.91%) individuals in the general
population died, whereas the corresponding figure for individuals with
ASD was 706 (2.60%; OR = 2.56; 95% CI 2.38–2.76). Cause-specific analyses
showed elevated mortality in ASD for almost all analysed diagnostic
categories. Mortality and patterns for cause-specific mortality were
partly moderated by gender and general intellectual ability.
Conclusions
Premature mortality was markedly increased in ASD owing to a multitude of
medical conditions.