Table 1.
Demographic and clinical characteristics of the Attention-Deficit/Hyperactive Disorder (ADHD) and typically developing groups
| ADHD | Typically developing | Group difference | |||
|---|---|---|---|---|---|
| Age (yrs) Mean (SD) Time 1 |
N=270 | 9.8 (3.1) | N=270 | 10.3 (3.3) | t(538)=1.69, p=0.09 |
| Time 2 | N=110 | 11.9 (2.9) | N=110 | 12.6 (2.9) | t(218)=1.73, p=0.08 |
| Time 3 | N=43 | 13.9 (2.9) | N=45 | 14.4 (2.3) | t(86)=1.06, p=0.29 |
| Time 4 | N=9 | 16.3 (2.1) | N=12 | 16.0 (1.5) | t(19)=037, p=0.72 |
|
| |||||
| Sex | Male 184 (68%) | Male 184 (68%) | N/A | ||
| Male : Female | Female 86 (32%) | Female 86 (32%) | |||
|
| |||||
| IQ Mean (SD) |
108 (15) | 108 (11) | t(500)=0.39, p=0.7 | ||
|
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| SES Mean (SD) | 47 (24) | 45 (20) | t(512)=1.15, p=0.25 | ||
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| On psychostimulant medication at study entry (yes/no) | 168/99 (data missing on 3 participants) | ||||
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| Ethnicity | White, non-Hispanic vs. others | ||||
| White, non-Hispanic | 207 (77%) | 219 (81%) | |||
| White, non-Hispanic | 17 (6%) | 8 (3%) | Χ(1)2=1.6, p=0.21 | ||
| African American | 36 (13%) | 29 (11%) | |||
| Other | 10 (4%) | 14 (5%) | |||
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| CBCL attention problems Mean (SD) |
72 (9) | N/A | |||
|
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| CBCL externalizing problems | 65 (11) | N/A | |||
|
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| DSM-IV diagnosed disorders, Number (%) | |||||
|
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| ODD | 91 (32%) | N/A | |||
|
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| Any mood disorder | 15 (5%) | N/A | |||
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| Any anxiety disorder | 17 (6%) | N/A | |||
|
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| Any tics | 16 (6%) | N/A | |||
|
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| Any learning disability | 28 (10%) | N/A | |||
Note: Missing data are reflected in the degrees of freedom. CBCL = Child Behavior Checklist; IQ= intelligence quotient; N/A = not applicable; ODD = oppositional defiant disorder; SES = socioeconomic status.