| 1. |
- Johansson Capusan, Andrea, 1970-
(författare)
-
Environmental and Genetic Influences in Attention Deficit Hyperactivity Disorder (ADHD) and its Comorbidities
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Research in past decades has demonstrated the persistence of attention deficit hyperactivity disorder (ADHD) into adulthood, but many questions regarding prevalence, causes, and comorbidities of ADHD in adults remain to be investigated. Previous research focusing on childhood ADHD identified high heritability. Genetic and environmental influences on ADHD symptoms in adults and their association with comorbid conditions are not fully understood.The overall aim of this thesis was to study adult ADHD symptoms in the population and investigate associations with substance use disorders (SUD) and binge eating. In all four papers, we used population-based self-report data from twins aged 20–46 years from the Swedish Twin Registry. We used twin methods to explore the role of genetic and environmental factors underlying ADHD symptoms and their comorbidities.Study I examined the phenotypic association between ADHD and various forms of SUD. ADHD in adults was strongly associated with alcohol abuse and alcohol dependence, illicit drug use and regular nicotine use, with no differences between ADHD subtypes and no apparent substance preference. In Studies II and IV, we used bivariate twin models to examine the role of genetic and environmental factors in the association of adult ADHD symptoms with alcohol dependence (II) and with binge eating (IV). For ADHD symptoms and alcohol dependence, 64% of the overlap was explained by common genetic factors. The remaining variance was accounted for by environmental factors specific for each twin, with no sex differences for the overlap. Similarly, 91% of the association between ADHD symptoms and binge-eating behaviour was explained by common genetic factors. In Study III, using a within-twin pair analysis, we demonstrated that although most of the association between adult ADHD symptoms and self-reported childhood maltreatment (an environmental risk factor for ADHD) was explained by familial (genetic and environmental) confounding, our results were also consistent with a causal interpretation.In conclusion, adult ADHD symptoms are associated with SUD and binge-eating behaviour. We replicated findings from adolescent studies regarding shared genetic risk factors for alcohol dependence and ADHD symptoms in adults. For binge eating, we showed for the first time that shared genetic factors mainly explained the association with ADHD symptoms. Alterations in mesolimbic reward processing as well as the frontal, executive and inhibitory systems have been described for ADHD, alcohol dependence and binge-eating behaviour, possibly suggesting common genetic and neurobiological factors for all three conditions. Results that support a causal hypothesis regarding the association between childhood maltreatment and ADHD symptoms in adults need follow-up in longitudinal clinical samples that can examine neurobiological underpinnings of environmental effects. Clinically, the results of this thesis support that ADHD in adults be considered and addressed in adults with SUD or binge-eating behaviour. Given the common genetic risk factors and the role of the early childhood environment, family interventions should be considered for these populations.
|
|
| 2. |
- Ollila, Hanna M., et al.
(författare)
-
Nightmares share genetic risk factors with sleep and psychiatric traits
- 2024
-
Ingår i: Translational Psychiatry. - : Springer Nature. - 2158-3188. ; 14:1
-
Tidskriftsartikel (refereegranskat)abstract
- Nightmares are vivid, extended, and emotionally negative or negative dreams that awaken the dreamer. While sporadic nightmares and bad dreams are common and generally harmless, frequent nightmares often reflect underlying pathologies of emotional regulation. Indeed, insomnia, depression, anxiety, or alcohol use have been associated with nightmares in epidemiological and clinical studies. However, the connection between nightmares and their comorbidities are poorly understood. Our goal was to examine the genetic risk factors for nightmares and estimate correlation or causality between nightmares and comorbidities. We performed a genome-wide association study (GWAS) in 45,255 individuals using a questionnaire-based assessment on the frequency of nightmares during the past month and genome-wide genotyping data. While the GWAS did not reveal individual risk variants, heritability was estimated at 5%. In addition, the genetic correlation analysis showed a robust correlation (rg > 0.4) of nightmares with anxiety (rg = 0.671, p = 7.507e−06), depressive (rg = 0.562, p = 1.282e−07) and posttraumatic stress disorders (rg = 0.4083, p = 0.0152), and personality trait neuroticism (rg = 0.667, p = 4.516e−07). Furthermore, Mendelian randomization suggested causality from insomnia to nightmares (beta = 0.027, p = 0.0002). Our findings suggest that nightmares share genetic background with psychiatric traits and that insomnia may increase an individual’s liability to experience frequent nightmares. Given the significant correlations with psychiatric and psychological traits, it is essential to grow awareness of how nightmares affect health and disease and systematically collect information about nightmares, especially from clinical samples and larger cohorts.
|
|
| 3. |
- Reynolds, Chandra A., et al.
(författare)
-
Gene-Environment Interplay in Physical, Psychological, and Cognitive Domains in Mid to Late Adulthood : Is APOE a Variability Gene?
- 2016
-
Ingår i: Behavior Genetics. - : Springer Nature Switzerland AG. - 0001-8244 .- 1573-3297. ; 46:1, s. 4-19
-
Tidskriftsartikel (refereegranskat)abstract
- Despite emerging interest in gene-environment interaction (GxE) effects, there is a dearth of studies evaluating its potential relevance apart from specific hypothesized environments and biometrical variance trends. Using a monozygotic within-pair approach, we evaluated evidence of G×E for body mass index (BMI), depressive symptoms, and cognition (verbal, spatial, attention, working memory, perceptual speed) in twin studies from four countries. We also evaluated whether APOE is a 'variability gene' across these measures and whether it partly represents the 'G' in G×E effects. In all three domains, G×E effects were pervasive across country and gender, with small-to-moderate effects. Age-cohort trends were generally stable for BMI and depressive symptoms; however, they were variable-with both increasing and decreasing age-cohort trends-for different cognitive measures. Results also suggested that APOE may represent a 'variability gene' for depressive symptoms and spatial reasoning, but not for BMI or other cognitive measures. Hence, additional genes are salient beyond APOE.
|
|
| 4. |
- Silventoinen, Karri, et al.
(författare)
-
Education in twins and their parents across birth cohorts over 100 years : an individual-level pooled analysis of 42 twin cohorts
- 2017
-
Ingår i: Twin Research and Human Genetics. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 1832-4274 .- 1839-2628.
-
Tidskriftsartikel (refereegranskat)abstract
- Whether monozygotic (MZ) and dizygotic (DZ) twins differ from each other in a variety of phenotypes is important for genetic twin modeling and for inferences made from twin studies in general. We analyzed whether there were differences in individual, maternal and paternal education between MZ and DZ twins in a large pooled dataset. Information was gathered on individual education for 218,362 adult twins from 27 twin cohorts (53% females; 39% MZ twins), and on maternal and paternal education for 147,315 and 143,056 twins respectively, from 28 twin cohorts (52% females; 38% MZ twins). Together, we had information on individual or parental education from 42 twin cohorts representing 19 countries. The original education classifications were transformed to education years and analyzed using linear regression models. Overall, MZ males had 0.26 (95% CI [0.21, 0.31]) years and MZ females 0.17 (95% CI [0.12, 0.21]) years longer education than DZ twins. The zygosity difference became smaller in more recent birth cohorts for both males and females. Parental education was somewhat longer for fathers of DZ twins in cohorts born in 1990-1999 (0.16 years, 95% CI [0.08, 0.25]) and 2000 or later (0.11 years, 95% CI [0.00, 0.22]), compared with fathers of MZ twins. The results show that the years of both individual and parental education are largely similar in MZ and DZ twins. We suggest that the socio-economic differences between MZ and DZ twins are so small that inferences based upon genetic modeling of twin data are not affected.
|
|
