| 5341. |
- Larsson, Henrik, 1975-
(författare)
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Commentary : Important design features to consider in observational research on the long-term outcomes of ADHD - reflections on Sibley et al. (2017) and Swanson et al. (2017)
- 2017
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Ingår i: Journal of Child Psychology and Psychiatry. - : Wiley-Blackwell. - 0021-9630 .- 1469-7610. ; 58:6, s. 679-681
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Tidskriftsartikel (refereegranskat)abstract
- In this issue of the Journal, Sibley etal. (2017) presented some important insights into how different assessment approaches influence the apparent persistence of ADHD into adulthood, while Swanson etal. (2017) presented interesting results regarding the long-term benefits (adult symptom reduction) and costs (adult height suppression) associated with the treatment of ADHD with stimulant medication. This commentary highlights that (a) future studies that attempt to explore the occurrence and predictors of persisting and remitting developmental trajectories of ADHD, as well as late-onset ADHD, need to be based on thorough assessment of ADHD in adulthood using a combination of self-ratings and other informants (parents), and that (b) observational studies of the long-term benefits and risk associated with ADHD medications will play an important role in future research and clinical guidelines.
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| 5342. |
- Larsson, Henrik, 1975-
(författare)
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Commentary : How can family-based quasi-experimental designs and national registers be used to address confounding in risk factor studies of psychopathology? A reflection on Obel et al. (2016)
- 2016
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Ingår i: Journal of Child Psychology and Psychiatry. - : Wiley-Blackwell. - 0021-9630 .- 1469-7610. ; 57:4, s. 538-539
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Tidskriftsartikel (refereegranskat)abstract
- Standard observational studies have reported a robust correlation between maternal smoking during pregnancy and risk of ADHD in offspring. In the accompanying article, Obel et al. used sibling-comparisons to explore the extent to which unmeasured familial confounding explains this association. This commentary highlights three important implications of the study. At a general level, Obel et al. illustrates how (1) family-based quasi-experimental designs and (2) national registers can be used to address confounding in risk factor studies of psychopathology. At a more specific level, the study suggests that maternal smoking during pregnancy is probably not a causal risk factor for ADHD.
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| 5343. |
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| 5344. |
- Larsson, Henrik, 1975-, et al.
(författare)
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Developmental trajectories of DSM-IV symptoms of attention-deficit/hyperactivity disorder : genetic effects, family risk and associated psychopathology
- 2011
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Ingår i: Journal of Child Psychology and Psychiatry. - : Wiley-Blackwell. - 0021-9630 .- 1469-7610. ; 52:9, s. 954-963
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: DSM-IV specifies three ADHD subtypes; the combined, the hyperactive-impulsive and the inattentive. Little is known about the developmental relationships underlying these subtypes. The objective of this study was to describe the development of parent-reported hyperactivity-impulsivity and inattention symptoms from childhood to adolescence and to study their associations with genetic factors, family risk, and later adjustment problems in early adulthood.METHOD: Data in this study comes from 1,450 twin pairs participating in a population-based, longitudinal twin study. Developmental trajectories were defined using parent-ratings of hyperactivity-impulsivity and inattention symptoms at age 8-9, 13-14, and 16-17. Twin methods were used to explore genetic influences on trajectories. Family risk measures included low socioeconomic status, large family size and divorce. Self-ratings of externalizing and internalizing problems in early adulthood were used to examine adjustment problems related to the different trajectory combinations.RESULTS: We found two hyperactivity-impulsivity trajectories (low, high/decreasing) and two inattention trajectories (low, high/increasing). Twin modeling revealed a substantial genetic component underlying both the hyperactivity-impulsivity and the inattention trajectory. Joint trajectory analyses identified four groups of adolescents with distinct developmental patterns of hyperactivity-impulsivity and inattention: a low/low group, a primarily hyperactive, a primarily inattentive and a combined (high/high) trajectory type. These trajectory combinations showed discriminant relations to adjustment problems in early adulthood. The hyperactive, inattentive and combined trajectory subtypes were associated with higher rates of family risk environments compared to the low/low group.CONCLUSION: Study results showed that for those on a high trajectory, hyperactivity decreased whereas inattention increased. The combinations of these trajectories lend developmental insight into how children shift from (i) a combined to inattentive subtype, and (ii) a hyperactive-impulsive to a combined subtype. This study suggests that ADHD subtypes cannot be viewed as discrete and stable categories.
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| 5345. |
- Larsson, Henrik, 1975-, et al.
(författare)
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Family income in early childhood and subsequent attention deficit/hyperactivity disorder : a quasi-experimental study
- 2014
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Ingår i: Journal of Child Psychology and Psychiatry. - : Wiley-Blackwell. - 0021-9630 .- 1469-7610. ; 55:5, s. 428-435
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Studies have found negative associations between socioeconomic position and attention deficit/hyperactivity disorder (ADHD), but it remains unclear if this association is causal. The aim of this study was to determine the extent to which the association between family income in early childhood and subsequent ADHD depends on measured and unmeasured selection factors.METHODS: A total of 811,803 individuals born in Sweden between 1992 and 2000 were included in this nationwide population-based cohort study. Diagnosis of ADHD was assessed via the Swedish national Patient Register and the Swedish Prescribed Drug Register. Annual family income during offspring's first 5 years in life was collected prospectively from the Swedish Integrated Database for Labour Market Research and divided into quartiles by (lower) family disposable income. We predicted ADHD from family income while controlling for covariates and also comparing differently exposed cousins and siblings to control for unmeasured familial confounding.RESULTS: The crude analyses suggested that children exposed to lower income levels were at increased risk for ADHD (HRQ uartile1 = 2.52; 95% CI, 2.42-2.63; HRQ uartile2 = 1.52; 95% CI, 1.45-1.58; HRQ uartile3 = 1.20; 95% CI, 1.14-1.15). This dose-dependent association decreased after adjustment for measured covariates (HRQ uartile1 = 2.09; 95% CI, 2.00-2.19; HRQ uartile2 = 1.36; 95% CI, 1.30-1.42; HRQ uartile3 = 1.13; 95% CI, 1.08-1.18). Although the association was attenuated in cousin comparisons (HRQ uartile1 = 1.61; 95% CI, 1.40-1.84; HRQ uartile2 = 1.28; 95% CI, 1.12-1.45; HRQ uartile3 = 1.14; 95% CI, 1.01-1.28) and sibling comparison models (HRQ uartile1 = 1.37; 95% CI, 1.07-1.75; HRQ uartile2 = 1.37; 95% CI, 1.12-1.68; HRQ uartile3 = 1.23; 95% CI, 1.04-1.45), it remained statistically significant across all levels of decreased disposable family income.CONCLUSIONS: Our results indicated that low family income in early childhood was associated with increased likelihood of ADHD. The link remained even after controlling for unmeasured selection factors, highlighting family income in early childhood as a marker of causal factors for ADHD.
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| 5346. |
- Larsson, Henrik, 1975-, et al.
(författare)
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Genetic and environmental influences on adult attention deficit hyperactivity disorder symptoms : a large Swedish population-based study of twins
- 2013
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Ingår i: Psychological Medicine. - : Cambridge University Press. - 0033-2917 .- 1469-8978. ; 43:1, s. 197-207
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Attention deficit hyperactivity disorder (ADHD) frequently persists into adulthood. Family and twin studies delineate a disorder with strong genetic influences among children and adolescents based on parent- and teacher-reported data but little is known about the genetic and environmental contribution to DSM-IV ADHD symptoms in adulthood. We therefore aimed to investigate the impact of genetic and environmental influences on the inattentive and hyperactive-impulsive symptoms of ADHD in adults.METHOD: Twin methods were applied to self-reported assessments of ADHD symptoms from a large population-based Swedish twin study that included data from 15 198 Swedish male and female twins aged 20 to 46 years.RESULTS: The broad heritability [i.e., A + D, where A is an additive genetic factor and D (dominance) a non-additive genetic factor] was 37% (A = 11%, D = 26%) for inattention and 38% (A = 18%, D = 20%) for hyperactivity-impulsivity. The results also indicate that 52% of the phenotypic correlation between inattention and hyperactivity-impulsivity (r = 0.43) was explained by genetic influences whereas the remaining part of the covariance was explained by non-shared environmental influences. These results were replicated across age strata.CONCLUSIONS: Our findings of moderate broad heritability estimates are consistent with previous literature on self-rated ADHD symptoms in older children, adolescents and adults and retrospective reports of self-rated childhood ADHD by adults but differ from studies of younger children with informant ratings. Future research needs to clarify whether our data indicate a true decrease in the heritability of ADHD in adults compared to children, or whether this relates to the use of self-ratings in contrast to informant data.
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| 5347. |
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| 5348. |
- Larsson, Henrik, 1975-, et al.
(författare)
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The heritability of clinically diagnosed attention deficit hyperactivity disorder across the lifespan
- 2014
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Ingår i: Psychological Medicine. - : Cambridge University Press. - 0033-2917 .- 1469-8978. ; 44:10, s. 2223-2229
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: No prior twin study has explored the heritability of clinically diagnosed attention deficit hyperactivity disorder (ADHD). Such studies are needed to resolve conflicting results regarding the importance of genetic effects for ADHD in adults. We aimed to estimate the relative contribution of genetic and environmental influences for clinically diagnosed ADHD across the lifespan with a specific focus on ADHD in adults.METHOD: Information on zygosity and sex was obtained from 59514 twins born between 1959 and 2001 included in the nationwide population-based Swedish Twin Registry. Clinical data for ADHD diagnoses (i.e. stimulant or non-stimulant medication for ADHD) were obtained from the Swedish Prescribed Drug Register (PDR) and from the National Patient Register (i.e. ICD-10 diagnosis of ADHD). Twin methods were applied to clinical data of ADHD diagnoses using structural equation modeling with monozygotic (MZ) and dizygotic (DZ) twins.RESULTS: The best-fitting model revealed a high heritability of ADHD [0.88, 95% confidence interval (CI) 0.83-0.92] for the entire sample. However, shared environmental effects were non-significant and of minimal importance. The heritability of ADHD in adults was also substantial (0.72, 95% CI 0.56-0.84).CONCLUSIONS: This study shows that the heritability of clinically diagnosed ADHD is high across the lifespan. Our finding of high heritability for clinically diagnosed ADHD in adults indicates that the previous reports of low heritability are best explained by rater effects, and that gene-identification studies of ADHD in adults need to consider pervasiveness (e.g. multiple raters) and developmentally (e.g. childhood-onset criteria) informative data.
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| 5349. |
- Larsson, Henrik, 1975-, et al.
(författare)
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The nature of psychopathology
- 2022
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Ingår i: JCPP Advances. - : John Wiley & Sons. - 2692-9384. ; 2:4
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Readers of JCPP Advances known that the dominant classification system (Diagnostic and Statistical Manual of Mental Disorders) in psychiatry and psychology conceptualizes psychopathology as discrete diagnostic categories. This measurement model builds on a strong assumption of a clear discontinuity between individuals who meet criteria for a diagnosis and those who don't fulfill diagnostic criteria. During the past decades we have seen huge efforts to test this assumption and explore alternative models, such as research from the hierarchical taxonomy of psychopathology consortia. Key findings of these efforts are reviewed and discussed in the December issue of JCPP Advances.
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| 5350. |
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