Coexisting Psychiatric Problems and Stressful Life Events in Adults With Symptoms of ADHD—A Large Swedish Population-Based Study of Twins

Abstract

Both women and men with ADHD are at increased risk for symptoms of other psychiatric disorders. They are also at increased risk for stressful life events.

Twin Study of the Relationship Between Adolescent Attention-Deficit/Hyperactivity Disorder and Adult Alcohol Dependence

“…However, important differences exist between that study and the current report: Elkins and colleagues did not incorporate a genetic component; there are potentially relevant differences in the ages at which the externalizing and alcohol-related phenotypes were assessed; and symptoms of the HYPER subtype did not uniquely predict age 18 alcohol abuse/ dependence (a slightly different phenotype than AD alone, used in the current report) in adjusted analyses. Furthermore, another recent phenotypic analysis of an adult sample found that the INATT ADHD subtype, but not the HYPER subtype, was signifi cantly associated with AD (Friedrichs et al, 2010). These inconsistencies could refl ect genuine population differences, changes in the relationships among phenotypes across the life span, or some other unknown factor; clearly, additional research is warranted.…”

“…In particular, conduct disorder (CD) and adolescent attention-defi cit/ hyperactivity disorder (ADHD) are often correlated with later alcohol use disorders, especially alcohol dependence (AD) (Arias et al, 2008;Friedrichs et al, 2010;Knop et al, 2009;Langley et al, 2010;Weiss et al, 1985;Whalen et al, 2002;White et al, 2001). Each of these disorders is characterized to some extent by externalizing behavior, raising the possibility that a general liability to such behavior contributes to the association among phenotypes.…”

Environmental and Genetic Influences in Attention Deficit Hyperactivity Disorder (ADHD) and its Comorbidities

“…Earlier studies reported a prevalence around 2.1 and 8.8% based on self-reports in the general population (54,61), and between 6.6% and 21.9% (61,62) in adult psychiatric outpatients. National diagnose register studies show an increase in clinically diagnosed cases between 2006 and 2011 from 0.11% to 0.48% (63).…”

“…One method, suggested by Barkley and Fisher (52) is a norm-based approach, which sets a cut-off at 1.5 or 2.0 standard deviations (SD) above the mean on the symptom count scales of hyperactivity/impulsivity and inattention. In American college students, a 2 SD cut-off resulted in prevalence similar to DSM-IV diagnosis (53), however, in other population studies, it rendered higher estimates, probably including subthreshold cases (54).…”

“…Participants, who were adult Swedish twins born between 1959 and 1985, where both individuals had survived their first birthday, received a personal login to the study's web page. The questionnaire contained around 1300 questions on lifestyle, physical and mental health (54,169,174). Questions were set in a "branching" format, which meant that subsequent questions were only asked if participants answered yes to the first "gate"-question/s in a section.…”