Journal of the American Academy of Child & Adolescent Psychiatry
New researchBeyond the Dual Pathway Model: Evidence for the Dissociation of Timing, Inhibitory, and Delay-Related Impairments in Attention-Deficit/Hyperactivity Disorder
Section snippets
Participants
Seventy-one families with an ADHD child participated in the Southampton arm of IMAGE.51 Seventy-one ADHD probands with a combined type diagnosis (mean [M] = 12.03 years, SD = 2.34 years), 65 unaffected siblings (M = 11.46 years, SD = 3.19 years) and 50 non-ADHD controls (M = 12.15 years, SD = 2.25 years) were included in the key analyses. Six siblings had ADHD and were excluded from the case–control and familiality analyses. Cases (between 6 and 17 years of age) with an existing full clinical
Results
Correlations were in general larger within domains (mean r = 0.22) than between domains (mean r = 0.11) (Table 2). Correlation between putative I-EDF and TPD measures were moderate. Correlations between putative DAv measures were weak and nonspecific. WM was associated with TPD measures and DRT and MStroop. For the principal components analysis there were four factors with Eigenvalues greater than 1 (Table 3). Component 1 (17.25% variance) had high loadings for SSRT, GNG and MStroop only
Discussion
ADHD is neuropsychologically heterogeneous, with different individuals affected to different degrees in different domains.12, 21 These results extend and refine the dual pathway model of ADHD heterogeneity.12, 13, 14 To our knowledge, our data provide the first evidence that Timing, Inhibition, and Delay deficits in ADHD are dissociable from each other and that substantial subgroups of patients are affected in only one domain. The results therefore run counter to a recent suggestion that timing
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Cited by (0)
This research was funded in part by ESRC CASE Award PTA-033-2003-00046 with Eli Lilley Ltd (to E.S.-B. and M.T. for P.B.).
Clinical data from the participants included in this paper contributed to the IMAGE project (Faraone; National Institutes of Health grant R01 MH62873-01A1).
Disclosure: Dr. Sonuga-Barke has served on the speakers' bureau and as a consultant for Shire and UCB Pharma. He has received research support from Janssen Cilag, Shire, Qbtech, and Flynn Pharma. He has served on the advisory board for Shire, Flynn Pharma, UCB Pharma, and Astra Zeneca. He has received conference support from Shire. Dr. Thompson has received education sponsorship from Eli Lilly and Janssen Cilag. She has received unrestricted research grants from Eli Lilly, Janssen Cilag, UCB Pharma, and Shire. She has served on the advisory board for Eli Lilly, UCB Pharma, and Shire. She has received drug trial support from Eli Lilly and Janssen Cilag. She has received lecture fees from Eli Lilly and Janssen Cilag. She has received funding for the support of Ph.D. students from Eli Lilly and Janssen Cilag. Dr. Bitsakou reports no biomedical financial interests or potential conflicts of interest.