Is Attention-Deficit/Hyperactivity Disorder (ADHD) a Dimension or a Category? What Does the Relationship Between ADHD Traits and Psychosocial Quality of Life Tell Us?

OBJECTIVE

The question of whether attention-deficit/hyperactivity disorder (ADHD) is a discrete category or a continuous dimension remains clinically relevant. We report the first examination of this question from the viewpoint of the relationship between ADHD traits and psychosocial quality of life (QoL), and whether the level of QoL declines markedly around a certain high ADHD trait range suggestive of a categorical boundary.

METHODS

Parents/caregivers of 1,967 schoolchildren aged 6 to 11 from the general population completed the Pediatric Quality of Life Inventory and the ADHD-Rating Scale IV. Piecewise linear and non-linear regression analyses were performed.

RESULTS

No evidence for a non-linear association or an abrupt change in the rate of decrease in QoL was observed in the high end of the ADHD traits continuum. Instead, the relationship was consistent with linearity.

CONCLUSION

Psychosocial QoL gradually declines in a linear manner as ADHD trait levels increase providing further support for a dimensional model.

Validation of the Weiss Functional Impairment Rating Scale (WFIRS-P) as a Functional Impairment Measure in a General Population of Schoolchildren

Functional impairment rating scales are few in numbers and have mainly been examined in clinical populations. The Weiss Functional Impairment Rating Scale-Parent report (WFIRS-P) is a case in point. We tested the psychometric properties of the WFIRS-P in the largest general population study to date and for the first time examined the factor structure of the scale in a general population setting. Participants were 2,027 schoolchildren aged 6 to 11. Parents/caregivers completed the WFIRS-P and criterion measures of quality of life, attention-deficit/hyperactivity disorder, and behavioral/emotional symptoms. Confirmatory factor analysis and convergent/divergent validity analyses supported a six-factor structure: family, life skills, self-concept, social activities, and the separation of the school domain into two smaller domains covering school learning and school behavior. Children with and without a history of referral differed significantly on all six domains supporting the external validity. In conclusion, the WFIRS-P was found to generate valid scores in a general population sample.

Do Autistic Traits Predict Outcome of Cognitive Behavioral Therapy in Pediatric Obsessive-Compulsive Disorder?

The first aim of this study was to explore whether children with obsessive compulsive disorder (OCD) and subclinical autistic traits can be differentiated from children with OCD without these traits based on clinical OCD-related characteristics, distinct OCD symptom patterns, and type of comorbidity. The second aim was to investigate whether autistic traits predict immediate and long-term outcome of exposure-based cognitive behavioral therapy (CBT) in pediatric OCD.The participants in this study were a total of 257 children and adolescents aged 7-17 years, recruited from Denmark, Norway, and Sweden as a part of the Nordic long-term OCD treatment study (NordLOTS). Inclusion criteria were an OCD diagnosis based on DSM-IV criteria and a Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS) total severity score of 16 or higher. No children with a diagnosis on the autism spectrum were included. An Autism Spectrum Screening Questionnaire (ASSQ) cut-off score of ≥ 17 was used to define the group of OCD patients with autistic traits and all participants were treated with 14 weekly sessions of manualized CBT.Comorbid attention-deficit/hyperactivity disorder and tic disorders, subclinical internalizing and externalizing symptoms, lower insight into OCD symptoms, more indecisiveness and pervasive slowness, and ordering/arranging OCD symptoms were found to be significantly associated with having OCD with autistic traits. No difference was found between the groups on treatment outcomes.Results suggest that children and adolescents with OCD and autistic traits portray a different clinical profile than those without these traits, but that CBT is equally effective for those with and without autistic traits.

The factor structure of attention-deficit/hyperactivity disorder in schoolchildren

BACKGROUND

Most studies support a bifactor model of childhood ADHD with two specific factors. However, several studies have not compared this model with a bifactor model with three specific factors, few have tested the actual strength of the factors, and none have examined whether "talks excessively" should be treated as a hyperactivity versus impulsivity symptom in children with ADHD.

AIMS

To examine the factor structure of ADHD symptoms and evaluate the relative strength of potential factors.

METHODS

Parent-reports on the ADHD-Rating Scale (ADHD-RS-IV) were collected for 2044 schoolchildren from the general population and 147 children with ADHD from a clinical sample. Single-, two- and three-(correlated and bi-)factor models were tested using confirmatory factor analysis.

RESULTS

Most models had a satisfactory fit. However, a correlated three-factor model where "talks excessively" was included as an indicator of impulsivity, and especially a bifactor model with one strong, well-defined general and two/three (ICD-10 defined) weak specific factors fit the data slightly better than the remaining models.

CONCLUSIONS

The factor structure is best characterized by a bifactor model with a strong general factor and two/three weaker specific factors. Therefore, we suggest emphasizing the ADHD-RS-IV total score rather than the subscale scores in clinical practice.

Testing the evolutionary advantage theory of attention-deficit/hyperactivity disorder traits

To reconcile the strong secular persistence of attention-deficit/hyperactivity disorder (ADHD) despite its impairing effects, ADHD traits have been postulated to offer an evolutionary advantage. It has been proposed that such advantages should in particular be observable under time-critical, novel, and resource-depleted conditions requiring response-readiness and high levels of scanning and exploration/foraging. Our objective was to provide the first behavioral test of this hypothesis. Schoolchildren from the general population with no/few (n = 56), mild (n = 50), moderate (n = 48), and severe (n = 48) ADHD traits, defined according to their ADHD-Rating Scale IV (ADHD-RS-IV) total score, participated in an exploratory foraging and response-readiness laboratory test. Here, children searched for coins hidden in locations of varying obscurity in an unfamiliar room for 1 min. Test-performance (number of coins found) adjusted for age, sex, and estimated IQ was analyzed categorically using multiple linear regression analyses and dimensionally by fitting a regression model including the ADHD-RS-IV score as a continuous measure. There were no differences in the mean number of coins between the No/Few (Mean = 7.82), Mild (Mean = 7.76), Moderate (Mean = 7.58), and Severe (Mean = 7.88) groups [F(3,195) = 0.24, p = 0.871]. Furthermore, excluding children with functional impairment, adjusting for verbal working memory and response inhibition, and stratifying for sex did not change these findings. Finally, continuous ADHD traits were not found to be related to test-performance [F(3,195) = 0.73, p = 0.536]. While our results do generally not support the evolutionary advantage theory (i.e., ADHD traits neither conferred an advantage nor a disadvantage), this does not disprove that ADHD traits may have offered advantages via other mechanisms.

How much impairment is required for ADHD? No evidence of a discrete threshold

BACKGROUND

A diagnosis of attention-deficit/hyperactivity disorder (ADHD) requires the presence of impairment alongside symptoms above a specific frequency and severity threshold. However, the question of whether that symptom threshold represents anything more than an arbitrary cutoff on a continuum of impairment requires further empirical study. Therefore, we present the first study investigating if the relationship between ADHD symptom severity and functional impairment is nonlinear in a way that suggests a discrete, nonarbitrary symptom level threshold associated with a marked step increase in impairment.

METHODS

Parent reports on the ADHD-Rating Scale (ADHD-RS-IV), the Weiss Functional Impairment Rating Scale (WFIRS-P), and the Strengths and Difficulties Questionnaire were collected in a general population sample of 1st, 2nd, and 3rd graders (N = 1,914-2,044).

RESULTS

Piecewise linear regression analyses and nonlinear regression modeling both demonstrated that the relationship between symptom severity (ADHD-RS-IV total score) and impairment (WFIRS-P mean score) was characterized by a gradual linear increase in impairment with higher symptom severity and no apparent step increase or changing rate of increase in impairment at a certain high ADHD-RS-IV total score level. Controlling for socioeconomic status, sex, and co-occurring conduct and emotional symptoms did not alter these results, though comorbid symptoms had a significant effect on impairment.

CONCLUSIONS

There was no clear evidence for a discrete, nonarbitrary symptom severity threshold with regard to impairment. The results highlight the continued need to consider both symptoms and impairment in the diagnosis of ADHD.

Subclinical autism spectrum symptoms in pediatric obsessive-compulsive disorder

The literature on subclinical autism spectrum (ASD) symptoms in pediatric obsessive-compulsive disorder (OCD) is scarce, and it remains unclear whether ASD symptoms are related to OCD severity. The aims of the present study were to assess the prevalence of ASD symptoms and age and sex differences in children and adolescents with OCD, and to explore the relation between ASD symptoms and OCD severity. This is the largest study of ASD symptoms in an OCD population to date, and the first directly aimed at elucidating sex and age differences in this matter. The study used baseline data from the Nordic Long-term OCD Treatment Study in which parents of 257 children and adolescents with OCD aged 7-17 completed the Autism Spectrum Screening Questionnaire. OCD severity was assessed with the Children's Yale-Brown Obsessive Compulsive Scale. Pediatric OCD patients were found to exhibit elevated rates of ASD symptoms compared to a norm group of school-age children. ASD symptoms were concentrated in a subgroup with a prevalence of 10-17 %. This subgroup was characterized by a male preponderance with a sex ratio of approximately 2.6:1, while children versus adolescents with OCD exhibited similar rates. Autism-specific social and communication difficulties were not related to OCD severity, while restricted repetitive behavior was positively related to OCD severity. The results indicate that clinicians need to be aware of ASD symptoms in children and adolescents with OCD since one out of ten exhibits such symptoms at a clinical sub-threshold.