A Systematic Evaluation of ADHD and Comorbid Psychopathology in a Population-Based Twin Sample

https://doi.org/10.1097/01.chi.0000166173.72815.83Get rights and content

ABSTRACT

Objective

Clinical and population samples demonstrate that attention-deficit/hyperactivity disorder (ADHD) occurs with other disorders. Comorbid disorder clustering within ADHD subtypes is not well studied.

Method

Latent class analysis (LCA) examined the co-occurrence of DSM-IV ADHD, oppositional defiant disorder (ODD), conduct disorder (CD), and depression symptoms in a population twin sample. The authors fit separate models for ADHD and comorbid disorder symptoms. Twin concordance ratios (monozygotic versus dizygotic) were compared examining genetic influence on class membership.

Results

LCA of ADHD symptoms resulted in seven classes including inattentive, combined, and hyperactive subtypes in 1,616 subjects. The few ADHD symptoms (53.4%) and severe inattentive (12.3%) classes were most frequent. LCA of ODD, CD, and depression symptoms in 1,587 subjects revealed five classes including ODD (19.4%), depression (14.5%), and two composite classes: ODD/CD (6.9%) and ODD/CD/depression (7.2%). Internalizing and externalizing comorbid disorders were present across all ADHD subtypes. Odds ratios (ORs) for twin concordance indicate genetic influence on severe inattentive (OR = 4.18; 95% confidence interval [CI], 1.52-11.53) and combined (OR = 5.25; 95% CI, 1.32-20.78) ADHD classes and ODD (OR = 1.49; 95% CI, 0.70-3.17), ODD/CD (OR = 3.32; 95% CI, 0.57-19.28), and ODD/CD/depression (OR = 1.20; 95% CI, 0.30-4.77) classes.

Conclusions

Internalizing and externalizing disorders did not cluster differentially within ADHD subtypes. LCA may provide a more precise characterization of comorbidity with ADHD.

Section snippets

Subjects

This sample contains 812 complete male and female twin pairs ages 7-19 years at time of interview identified from the Missouri Twin Registry from 1996 through 2002 as part of a study to examine the genetic epidemiology of ADHD. A screening interview assessed the presence of three past or present inattentive symptoms and three past or present hyperactive/impulsive symptoms for each twin. Families were included in the study if either twin of the pair exhibited three or more present or past

Characteristics of Sample, DSM-IV ADHD Subtype, and Co-occurring Disorders

The total sample consists of 1,624 subjects (213 MZ pairs, 599 DZ pairs [151 male MZ, 180 male DZ, 352 DZ opposite sex]) with a mean age of 12.97 ± 3.2 years. Male subjects composed 62.5% of the study population. Based on DSM-IV criteria for ADHD, 163 (10%) subjects were diagnosed as the primarily inattentive subtype, 24 (1.5%) the predominantly hyperactive subtype, and 180 (11.1%) as the combined subtype. Cases in each subtype were predominantly male (83% inattentive, 75% hyperactive, 86%

DISCUSSION

We sought to systematically assess the aggregation of childhood psychiatric symptoms and disorders in a population-based sample of male and female twins. Examination of ADHD, ODD, CD, and depression using latent class analysis and DSM-IV disorder criteria resulted in five main findings. First, the seven classes identified in this population are remarkably similar to the structure of observed classes in previous reports (Rasmussen et al., 2002b).

Second, diagnoses of ODD, CD, and depression

REFERENCES (27)

  • SA Burt et al.

    Sources of covariation among attention-deficit/hyperactivity disorder, oppositional defiant disorder, and conduct disorder: the importance of the shared environment

    J Abnorm Psychol

    (2001)
  • SA Burt et al.

    Parent-child conflict and the comorbidity among child externalizing disorders

    Arch Gen Psychiatry

    (2003)
  • C Caron et al.

    Comorbidity in child psychopathology: concepts, issues, and research strategies

    J Child Psychol Psychiatry

    (1991)
  • Cited by (75)

    • Comorbidity classes and associated impairment, demographics and 9/11-exposures in 8,236 children and adolescents

      2018, Journal of Psychiatric Research
      Citation Excerpt :

      Olino et al. (2012) identified, in addition to a no disturbance class, other three classes, which were comparable to classes reported in our study: (1) a class with high probability of MDD, similar to our MDD class; (2) a class with predominantly elevated rates of externalizing disorders (substance use disorders; SUDs), but also moderate rates of MDD (58.8%), similar to our EXT class, which was characterized by high probability of externalizing symptoms and moderate probability of MDD symptoms (mean=40.1%); (3) a class with high rates of MDD and externalizing disorders (SUDs), and intermediate rates of anxiety disorders and PTSD, similar to our Distress/EXT class, which was defined by high probability of MDD and externalizing (CD) symptoms and intermediate probabilities of PTSD (mean=43.4%) and anxiety disorders (mean=47.2%) symptoms. A profile with comorbid CD and MDD symptoms was also observed in the only other study that analyzed these disorders in youth (Volk et al., 2005). Consistent with previous findings (Ferdinand et al., 2006; van Lang et al., 2006), symptom profiles defined by non-comorbid anxious symptomatology were not identified.

    • Disruptive Behavior Disorders in Children 0 to 6 Years Old

      2017, Child and Adolescent Psychiatric Clinics of North America
    View all citing articles on Scopus

    This work is supported by NIH grant MH52813 (Dr. Todd).

    Disclosure: The authors have no financial relationships to disclose.

    View full text