Estimation of Prevalence of DSM-IV and Latent Class-Defined ADHD Subtypes in a Population-Based Sample of Child and Adolescent Twins

Abstract

The goal of this study is to determine the prevalence and age of onset of Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSMIV; American Psychiatric Association, 1994) and latent class-derived attention deficit/hyperactivity disorder (ADHD) subtypes in a population-based twin sample of boys and girls. Missouri birth records identified families with a twin pair 7 to 18 years of age. Telephone screening interviews for ADHD symptoms were completed for 5007 families. Diagnostic assessments were administered to 564 families with at least one twin meeting screening criteria, plus 183 control families. Prevalence and age of onset for both ADHD nosologies were calculated by sex and zygosity from parent report data. The prevalence of any DSM-IV ADHD was 6.2% overall, 7.4% in boys and 3.9% in girls. The inattentive subtype was most common in boys; the combined subtype was most common in girls. The mean age of onset of symptoms in children with any DSM-IV ADHD was 3.5 years, with no significant differences between boys and girls. Prevalences of latent class defined ADHD subtypes also varied by sex with the severe inattentive and combined classes more common in boys than girls. The age of onset of symptoms did not differ between boys and girls but were higher than in the DSM-IV subtypes. Findings in this twin sample showed that clinically significant ADHD, defined by either DSM-IV or latent class criterion, has an early age of onset and is more common in boys than girls. As clinical samples are most commonly composed of male combined subtypes, the inattentive subtype of both sexes in the general population is an under- treated segment of the general population.

Validation of population‐based ADHD subtypes and identification of three clinically impaired subtypes

“…No comparable studies have been conducted in a non-twin sample. As noted in Neuman et al, 2005, the prevalence of ADHD subtypes in Australian non-twin siblings of twins is similar to that reported in Missouri twins . Whether there would be differences in comorbidity profiles for non-twins is unknown.…”

Co-Morbidity in Mathematical Learning Disabilities: Rule or Exception?

“…This proportion was significantly higher (p<.0001) than that found in the general population: 3-9% (Airaksinen, Michelsson, & Jokela, 2004;Neuman et al, 2005). Nine boys (52.94%) and six girls (46.15%) in our dataset had a co-morbid diagnosis of ADHD.…”

Individual differences in the functional neuroanatomy of inhibitory control

“…Many clinical conditions characterised by impaired impulse control are more prevalent in males than females. For example, a survey with over 9000 respondents revealed that men have a higher risk of impulse control and substance use psychiatric disorders (Kessler et al, 2005) while Attention Deficit and Hyperactivity Disorder (Neuman et al, 2005) and conduct disorder (Eme and Kavanaugh, 1995) are also more prevalent in males. Whether or not such disorders, which are multi-faceted and may have multiple causes, reflect inherent differences in how males and females implement inhibitory control is unknown.…”