Has the attention deficit hyperactivity disorder phenotype become more common in children between 2004 and 2014? Trends over 10 years from a Swedish general population sample.

Background: Studies have reported increases in clinically diagnosed and treated attention deficit hyperactivity disorder (ADHD) during the last decade, but it is unclear if this reflects an increase in the underlying ADHD phenotype. We aimed to clarify if there has been an increase in the prevalence of ADHD-like traits in the general population from 2004 to 2014.

Method: Data were collected from 9-year-old twins (19,271), participating in the population-based Child and Adolescent Twin Study in Sweden between 2004 and 2014.

Sex-specific manifestation of genetic risk for attention deficit hyperactivity disorder in the general population.

Background: Attention deficit hyperactivity disorder (ADHD) is more commonly diagnosed in males than in females. A growing body of research suggests that females with ADHD might be underdiagnosed or receive alternative diagnoses, such as anxiety or depression. Other lines of reasoning suggest that females might be protected from developing ADHD, requiring a higher burden of genetic risk to manifest the disorder.

Maternal Smoking in Pregnancy and Offspring Depression: a cross cohort and negative control study.

Previous reports suggest that offspring of mothers who smoke during pregnancy have greater risk of developing depression. However, it is unclear whether this is due to intrauterine effects. Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC) from the UK (N = 2,869), the Nord-Trøndelag health study (HUNT) from Norway (N = 15,493), the Pelotas 1982 Birth Cohort Study from Brazil (N = 2,626), and the Swedish Sibling Health Cohort (N = 258 sibling pairs), we compared associations of maternal smoking during pregnancy and mother's partner's smoking during pregnancy with offspring depression and performed a discordant sibling analysis.

Genetic and environmental contributions to the association between ADHD and affective problems in early childhood-A Swedish population-based twin study.

Few twin studies have explored the relative contribution of genetic and environmental factors to the association between attention deficit hyperactivity disorder (ADHD) and affective problems, and no study has focused on preschool children. We used the classical twin design to explore the genetic and environmental overlap between ADHD symptoms and affective problems in preschool children, based on 879 five-year-old twin pairs born in Sweden 2004-2005. Questionnaire-based parent-ratings were used to measure ADHD symptoms and affective problems.

Association Between Deliberate Self-harm and Violent Criminality.

Importance: Individuals who self-harm may have an increased risk of aggression toward others, but this association has been insufficiently investigated. More conclusive evidence may affect assessment, treatment interventions, and clinical guidelines.

Objective: To investigate the association between nonfatal self-harm and violent crime.

Association of Perinatal Risk Factors With Obsessive-Compulsive Disorder: A Population-Based Birth Cohort, Sibling Control Study.

Importance: Perinatal complications may increase the risk of obsessive-compulsive disorder (OCD). Previous reports were based on small, retrospective, specialist clinic-based studies that were unable to rigorously control for unmeasured environmental and genetic confounding.

Objective: To prospectively investigate a wide range of potential perinatal risk factors for OCD, controlling for unmeasured factors shared between siblings in the analyses.

Maternal smoking during pregnancy and offspring's tobacco dependence. A study of exposure-discordant sibling pairs.

Background: Prenatal exposure to maternal smoking has previously been linked to tobacco dependence, but confounding from genetic and early-environmental factors is of concern. The aim of this study was to clarify if maternal smoking during pregnancy may affect the onset and manifestations of tobacco dependence after taking such factors into account.

Methods: The study is based on a matched cohort of 1538 siblings discordant for prenatal exposure to maternal smoking, who participated in a survey conducted in 2010 in Sweden.

Measuring tobacco dependence in the general population: Evaluation of the Cigarette Dependence Scale (CDS-12) and its adaptation to smokeless tobacco use (STDS-12) in two Swedish surveys.

Aims: The 12-item Cigarette Dependence Scale (CDS-12) is an instrument suitable to assess tobacco dependence in non-clinical populations. The aim of this study was twofold: a) to evaluate the scale's performance in a smoking population including non-daily smokers; b) to explore the scale's adaptation to the assessment of dependence on smokeless tobacco.

Methods: In a cross-sectional study we investigated performance and construct validity of the CDS-12 and of its adaptation to smokeless tobacco (STDS-12) in two Swedish population samples.

Is Physical Activity Causally Associated With Symptoms of Attention-Deficit/Hyperactivity Disorder?

Objective: Emerging evidence suggests that physical activity (PA) enhances cognition and may be a protective factor for attention-deficit/hyperactivity disorder (ADHD). Yet the impact of PA on ADHD symptoms has been investigated only in a few undersized, nonrandomized, and retrospective studies. We examined the effect of PA during late adolescence on ADHD symptoms in early adulthood while controlling for unmeasured genetic and shared environmental confounding.

In-utero exposure to maternal smoking is not linked to tobacco use in adulthood after controlling for genetic and family influences: a Swedish sibling study.

Previous studies have linked maternal smoking during pregnancy with regular tobacco use in offspring, but findings are not consistent and confounding from genetic and environmental factors have not fully been taken into account. A comparison between siblings discordant for prenatal smoking exposure adjusts for confounding by shared familial (i.e.

Exposure to maternal smoking during pregnancy as a risk factor for tobacco use in adult offspring.

Nicotine from maternal smoking during pregnancy can cross the placental barrier, possibly resulting in fetal brain sensitization, as indicated by studies in which prenatal exposure to maternal smoking was associated with an increased risk of tobacco use among adolescent offspring. We investigated whether this association persists beyond adolescence by studying cigarette smoking and the use of snus (Swedish oral moist snuff) among 983 young adults from a prospective cohort study conducted in Stockholm, Sweden, between 2006 and 2010. Self-reported questionnaire data were linked with data from national population-based registers from 1983 onward.

Prenatal exposure to tobacco and future nicotine dependence: population-based cohort study.

Background: Maternal smoking during pregnancy may increase the risk of nicotine dependence, especially in girls, but data are conflicting and confounding by other familial factors cannot be ruled out.

Aims: To clarify the relationship between prenatal tobacco exposure and adolescent tobacco uptake and dependence in boys and girls respectively, while taking confounding factors into close consideration.

Method: We conducted a prospective longitudinal study, comprising 3020 Swedish youths followed from 11 to 18 years of age.