| 21. |
- Lichtenstein, P., et al.
(författare)
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Associations between conduct problems in childhood and adverse outcomes in emerging adulthood: a longitudinal Swedish nationwide twin cohort
- 2020
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Ingår i: Journal of Child Psychology and Psychiatry and Allied Disciplines. - : Wiley. - 0021-9630 .- 1469-7610. ; 61:7, s. 798-806
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Tidskriftsartikel (refereegranskat)abstract
- Background We examined whether childhood conduct problems predicted a wide range of adverse outcomes in emerging adulthood and whether the association with internalizing problems remained after adjusting for general comorbidity and externalizing problems. Methods Participants were 18,649 twins from the Child and Adolescent Twin Study in Sweden. At age 9/12, parents rated their children on eight conduct problems. Adverse outcomes were retrieved from national registers in emerging adulthood (median follow‐up time = 9.2 years), including diagnoses of six psychiatric disorders, prescriptions of antidepressants, suicide attempts, criminality, high school ineligibility, and social welfare recipiency. We estimated risk for the separate outcomes and examined if conduct problems predicted an internalizing factor above and beyond a general comorbidity and an externalizing factor. We used twin analyses to estimate genetic and environmental contributions to these associations. Results On the average, each additional conduct symptom in childhood was associated with a 32% increased risk of the adverse outcomes in emerging adulthood (mean hazard ratio = 1.32; range = 1.16, 1.56). A latent childhood conduct problems factor predicted the internalizing factor in emerging adulthood (βboys = .24, standard error, SE = 0.03; βgirls = .17, SE = 0.03), above and beyond its association with the externalizing (βboys = 0.21, SE = 0.04; βgirls = 0.17, SE = 0.05) and general factors (βboys = 0.45, SE = 0.03; βgirls = 0.34, SE = 0.04). These associations were differentially influenced by genetic and environmental factors. Conclusions It is important to monitor boys and girls with conduct problems not only for future externalizing problems, but also for future internalizing problems. Prevention of specific outcomes, however, might require interventions at different levels.
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| 22. |
- Lundström, Sebastian, et al.
(författare)
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Autism spectrum disorders and autistic like traits: similar etiology in the extreme end and the normal variation.
- 2012
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Ingår i: Archives of General Psychiatry. - Chicago, USA : American Medical Association (AMA). - 0003-990X .- 1538-3636. ; 69:1, s. 46-52
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: Autism spectrum disorders (ASDs) have been suggested to represent the extreme end of a normal distribution of autisticlike traits (ALTs). However, the evidence of this notion is inconclusive. OBJECTIVE: To study whether there are similar genetic and/or environmental etiologies behind ASDs and ALTs. DESIGN: A nationwide twin study. PARTICIPANTS: Consenting parents of all Swedish twins aged 9 and 12 years, born between July 1, 1992, and December 31, 2001 (n = 19 208), were interviewed by telephone to screen for child psychiatric conditions, including ASDs. MAIN OUTCOME MEASURES: Two validated cutoffs for ASDs, 2 cutoffs encompassing the normal variation, and 1 continuous measure of ALTs were used with DeFries-Fulker extreme-end analyses and standard twin study methods. RESULTS: We discerned a strong correlation between the 4 cutoffs and the full variation of ALTs. The correlation was primarily affected by genes. We also found that the heritability for the 4 cutoffs was similar. CONCLUSION: We demonstrate an etiological similarity between ASDs and ALTs in the normal variation and, with results from previous studies, our data suggest that ASDs and ALTs are etiologically linked.
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| 23. |
- Magnusson, Patrik K. E., et al.
(författare)
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The Swedish Twin Registry : establishment of a biobank and other recent developments
- 2013
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Ingår i: Twin Research and Human Genetics. - Cambridge, United Kingdom : Cambridge University Press. - 1832-4274 .- 1839-2628. ; 16:1, s. 317-329
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 24. |
- Melke, Jonas, 1971, et al.
(författare)
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A polymorphism in the serotonin receptor 3A (HTR3A) gene and its association with harm avoidance in women.
- 2003
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Ingår i: Archives of general psychiatry. - : American Medical Association (AMA). - 0003-990X. ; 60:10, s. 1017-23
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The brain neurotransmitter serotonin is known to affect various aspects of human behavior, including personality traits. Serotonin receptor type 3 is a ligand-gated channel encoded by 2 different subunit genes, HTR3A and HTR3B. A polymorphism (C178T) in the 5' region of the HTR3A gene has recently been identified and suggested to be of functional importance. OBJECTIVE: To elucidate the possible association between the C178T polymorphism in the HTR3A gene and personality traits in women. DESIGN: Two independent samples of 35- to 45-year-old Swedish women were recruited using the population register. Sample 1 (n = 195) was assessed via the Karolinska Scales of Personality and the Temperament and Character Inventory; sample 2 (n = 175) was assessed using the latter only. Both samples were genotyped with respect to the C178T polymorphism in the HTR3A gene. The A1596G polymorphism in the same gene was also investigated. RESULTS: A significant association between C178T genotype and the Temperament and Character Inventory factor harm avoidance was observed in sample 1 (corrected for multiple comparisons P =.04); this finding was subsequently replicated in sample 2 (P =.004) (pooled populations: P<.001). In the pooled sample, all harm avoidance subscales were found to be significantly associated with the C178T polymorphism: anticipatory worry (P =.001), fear of uncertainty (P<.001), shyness (P<.001), and fatigability and asthenia (P =.008). In addition, a significant association was found in sample 1 between the C178T polymorphism and the Karolinska Scales of Personality nonconformity factor (corrected P =.002), including the subscales of social desirability (P<.001), indirect aggression (P =.002), verbal aggression (P =.05), and irritability (P<.001). Participants homozygous for the less common T allele (<4%) differed from the remaining women by displaying lower ratings on harm avoidance and nonconformity. CONCLUSION: The C178T polymorphism in the HTR3A gene may affect the personality trait of harm avoidance in women.
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| 25. |
- Pettersson, Erik, et al.
(författare)
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Birth weight as an independent predictor of ADHD symptoms : a within-twin pair analysis
- 2015
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Ingår i: Journal of Child Psychology and Psychiatry. - Hoboken, USA : Wiley-Blackwell. - 0021-9630 .- 1469-7610. ; 56:4, s. 453-459
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Tidskriftsartikel (refereegranskat)abstract
- Background Studies have found an association between low birth weight and ADHD, but the nature of this relation is unclear. First, it is uncertain whether birth weight is associated with both of the ADHD dimensions, inattentiveness and hyperactivity-impulsivity. Second, it remains uncertain whether the association between birth weight and ADHD symptom severity is confounded by familial factors.Method: Parents of all Swedish 9- and 12-year-old twins born between 1992 and 2000 were interviewed for DSM-IV inattentive and hyperactive-impulsive ADHD symptoms by the Autism - Tics, AD/HD and other Comorbidities (A-TAC) inventory (N = 21,775 twins). Birth weight was collected prospectively through the Medical Birth Registry. We used a within-twin pair design to control for genetic and shared environmental factors.Results: Reduced birth weight was significantly associated with a mean increase in total ADHD (β = -.42; 95% CI: -.53, -.30), inattentive (β = -.26; 95% CI: -.33, -.19), and hyperactive-impulsive (β = -.16; 95% CI: -.22, -.10) symptom severity. These results imply that a change of one kilogram of birth weight corresponded to parents rating their child nearly one unit higher (going from "no" to "yes, to some extent" on a given symptom) on the total ADHD scale. These associations remained within pairs of MZ and DZ twins, and were also present when restricting the analyses to full term births.Conclusions: There is an independent association between low birth weight and all forms of ADHD symptoms, even after controlling for all environmental and genetic confounds shared within twin pairs. These results indicate that fetal growth restriction (as reflected in birth weight differences within twin pairs) and/or the environmental factors which influence it is in the casual pathway leading to ADHD.
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| 26. |
- Quinn, Patrick D., et al.
(författare)
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Childhood attention-deficit/hyperactivity disorder symptoms and the development of adolescent alcohol problems : A prospective, population-based study of Swedish twins
- 2016
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Ingår i: American Journal of Medical Genetics Part B. - Hoboken, USA : John Wiley & Sons. - 1552-4841 .- 1552-485X. ; 171:7, s. 958-970
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Tidskriftsartikel (refereegranskat)abstract
- Children with attention-deficit/hyperactivity disorder (ADHD) are at increased risk of problematic alcohol and other substance use in adolescence. This study used data from an ongoing, prospective, population-based twin study of Swedish children and adolescents to evaluate the extent to which the association between ADHD symptoms and alcohol problems reflects a unique source of genetic or environmental risk related to ADHD versus a broader predisposition to youth externalizing behavior. We used all available data from same-sex monozygotic (MZ) and dizygotic (DZ) twins on ADHD symptoms in childhood (age 9/12; N = 15,549) and alcohol problems in late adolescence (age 18; N = 2,564). Consistent with prior longitudinal studies, the phenotypic association between hyperactive/impulsive ADHD symptoms and alcohol problems was small in magnitude, whereas the association for inattentive symptoms was even weaker. Additive genetic influences explained 99.8% of the association between hyperactive/impulsive symptoms and alcohol problems. Furthermore, we found that the genetic risk specifically associated with hyperactive/impulsive symptoms was attenuated when estimated in the context of externalizing behavior liability during childhood, of which ADHD symptoms were specific expressions. In sensitivity analyses exploring hyperactivity in mid-adolescence, we found a similar pattern of genetic associations. These results are consistent with previous findings of genetically driven overlap in the etiology of ADHD and problematic alcohol use. At least some of this co-occurrence may result from a general predisposition to externalizing behaviors in youth. © 2015 Wiley Periodicals, Inc.
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| 27. |
- Ronald, A., et al.
(författare)
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A twin study of autism symptoms in Sweden
- 2011
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Ingår i: Molecular Psychiatry. - London, United Kingdom : Nature Publishing Group. - 1359-4184 .- 1476-5578. ; 16:10, s. 1039-1047
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Tidskriftsartikel (refereegranskat)abstract
- This study aimed to identify empirically the number of factors underlying autism symptoms-social impairments, communication impairments, and restricted repetitive behaviors and interests-when assessed in a general population sample. It also investigated to what extent these autism symptoms are caused by the same or different genetic and environmental influences. Autistic symptoms were assessed in a population-based twin cohort of >12,000 (9- and 12-year-old) children by parental interviews. Confirmatory factor analyses, principal component analyses and multivariate structural equation model fitting were carried out. A multiple factor solution was suggested, with nearly all analyses pointing to a three-factor model for both boys and girls and at both ages. A common pathway twin model fit the data best, which showed that there were some underlying common genetic and environmental influences across the different autism dimensions, but also significant specific genetic effects on each symptom type. These results suggest that the autism triad consists of three partly independent dimensions when assessed in the general population, and that these different autism symptoms, to a considerable extent, have partly separate genetic influences. These findings may explain the large number of children who do not meet current criteria for autism but who show some autism symptoms. Molecular genetic research may benefit from taking a symptom-specific approach to finding genes associated with autism.
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| 28. |
- Ronald, A., et al.
(författare)
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Symptoms of Autism and ADHD: A Swedish Twin Study Examining Their Overlap
- 2014
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Ingår i: Journal of Abnormal Psychology. - Washington DC, USA : American Psychological Association (APA). - 0021-843X .- 1939-1846. ; 123:2, s. 440-451
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Tidskriftsartikel (refereegranskat)abstract
- Autism spectrum disorders (ASD) and attention deficit hyperactivity disorder (ADHD) show high comorbidity. The following questions were addressed regarding their specific symptoms: What is the factor structure of ASD and ADHD symptoms, to what degree do different symptom domains cluster together, to what extent are these domains caused by the same genetic and environmental influences, and what is the best model of their co-occurrence? A population-based twin cohort of over 17,000 9- and 12-year-olds were assessed using the Autism-Tics, AD/HD, and other Comorbidities parental interview inventory. Principal component analyses were conducted, and symptom domain clustering was assessed. Four multivariate twin models were compared. Factors split into three ASD (social impairments, communication impairments, and restricted repetitive behaviors and interests), and three ADHD (inattention, hyperactivity, and impulsivity) symptom domains. Some ASD-ADHD symptom domain combinations clustered together often, although others not at all. A two-factor common pathway model fit the data, suggesting that ASD and ADHD symptom domains tap into separate "ASD" and "ADHD" latent factors that showed high genetic overlap. All subdomains also showed significant specific genetic and environmental influences, reflecting the etiological heterogeneity both within and between ASD and ADHD. These findings support the conceptual distinction of ASD and ADHD, and demonstrate the considerable natural co-occurrence of particular ASD/ADHD symptom domains. The results imply that more children with 1 condition show features of the other condition than show complete comorbidity. Emphasis on symptom co-occurrence, rather than complete comorbidity between disorders, may help focus clinical approaches and advance molecular genetic research.
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| 29. |
- Söderström, Henrik, 1966, et al.
(författare)
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Reduced regional cerebral blood flow in non-psychotic violent offenders.
- 2000
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Ingår i: Psychiatry research. - 0165-1781 .- 1872-7123. ; 98:1, s. 29-41
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Tidskriftsartikel (refereegranskat)abstract
- The present study was designed to replicate previously reported findings of abnormal frontal and/or temporal cerebral blood flow in violent offenders and to control for the influence of major mental disorder (MMD), substance abuse, and current medication. HMPAO-SPECT-CBF and MRI scans from pretrial forensic psychiatric investigations of 21 subjects convicted of impulsive violent crimes were retrospectively re-evaluated. In 16/21 subjects, visual assessment of SPECT scans showed some hypoperfusion in the temporal and/or frontal lobes. MRI showed no corresponding structural damage. Quantified regional cerebral blood flow (rCBF) in defined regions of interest was compared between index cases and 11 healthy control subjects. Index subjects had significant reductions in the right angular gyrus and the right medial temporal gyrus, bilaterally in the hippocampus, and in the left white frontal matter, but they had significantly increased rCBF in the parietal association cortex bilaterally. The aberrations were as frequent and severe among the subjects without MMD, substance abuse, and current medication (n=7) as in the entire group of index subjects.
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| 30. |
- Söderström, Henrik, 1966, et al.
(författare)
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The childhood-onset neuropsychiatric background to adulthood psychopathic traits and personality disorders.
- 2005
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Ingår i: Comprehensive psychiatry. - : Elsevier BV. - 0010-440X. ; 46:2, s. 111-6
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Tidskriftsartikel (refereegranskat)abstract
- Childhood conduct disorder (CD) and adult psychopathic traits according to the Psychopathy Checklist Revised (PCL-R) were the closest psychiatric covariates to repeated violent crimes and aggression among offenders under forensic psychiatric investigation in Sweden. As psychopathy is not included in the present psychiatric diagnostic systems, we compared total and factor PCL-R scores to Axis I disorders, including childhood-onset neuropsychiatric disorders, and to Axis II personality disorders, to establish the convergence of psychopathic traits with other psychiatric diagnoses, and to identify possible unique features. Psychopathic traits were positively correlated with bipolar mood disorder and negatively with unipolar depression. The total PCL-R scores as well as the Factor 2 (unemotionality) and Factor 3 (behavioral dyscontrol) scores were significantly correlated with attention-deficit/hyperactivity disorder, Asperger's syndrome/high-functioning autistic traits, CD, substance abuse, and the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Cluster B personality disorders. The interpersonal Factor 1 showed none of these correlations and may capture features that are specific to psychopathy, distinguishing core psychopathy from other diagnostic definitions.
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