TABLE 1.
Clinical and Demographic Characteristics of the Attention-Deficit/Hyperactivity Disorder (ADHD) Group Used for the Dimensional and Subgroup Analysis
| ADHD-CT (n = 63) | High EL (n = 18) | Low EL (n = 20) | TDC (n = 19) | |
|---|---|---|---|---|
| Male, n (%) | 50 (79) | 16 (89) | 14 (70) | 15 (79) |
| Age, y | 9.4 (2.0) | 9.9 (1.6) | 9.5 (1.9) | 10.5 (1.9) |
| Eyes, n open (%) | 28 (44) | 8 (44) | 13 (65) | 11 (58) |
| Race, n (%) | ||||
| White | 29 (46) | 7 (39) | 8 (40) | 12 (63) |
| African American | 10 (16) | 5 (28) | 5 (25) | 4 (21) |
| Asian Pacific Islander | 4 (6) | 0 (0) | 2 (10) | 1 (5) |
| American Indian | 0 | 0 | 0 | 0 |
| Other | 14 (22) | 5 (27) | 5 (25) | 2 (11) |
| Mixed | 6 (10) | 1 (6) | 0 (0) | 0 |
| Ethnicity, n (%) | ||||
| Hispanic | 23 (37) | 9 (50) | 6 (30) | 3 (16) |
| SES, n (%) | ||||
| 1 (low) | 4 (6) | 1 (6) | 1 (5) | 2 (11) |
| 2 | 7 (11) | 4 (22) | 2 (10) | 0 |
| 3 | 7 (11) | 3 (16) | 3 (15) | 3 (16) |
| 4 | 21 (34) | 5 (28) | 5 (25) | 6 (32) |
| 5 (high) | 24 (38) | 5 (28) | 9 (45) | 8 (41) |
| Full Scale IQ | 105.5 (14.6) | 98.9 (16.8) | 109.3 (13.5) | 109.8 (13.7) |
| Maximum movement (mm) | 1.33 (1.5) | 1.15 (2.0) | 1.88 (1.4) | 1.88 (2.0) |
| Mean framewise displacement (mm) | 0.13 (0.05) | 0.13 (0.06) | 0.14 (0.05) | 0.17 (0.02) |
| CPRS-R: Emotional Lability Scalea | 58 (14.6) | 77.9 (8.5) | 44.5 (4.2) | 44.5 (4.3) |
| (range) | (41–90) | (65–90) | (41–54) | (41–55) |
| CPRS-R: Hyperactivity Scaleb | 72 (10.8) | 76.5 (8.4) | 71.8 (11.6) | 45.9 (5.5) |
| (range) | (54–90) | (56–90) | (54–90) | (43–67) |
| Psychiatric comorbidity (%) | 27 | 22 | 15 | 0 |
Note: Means and standard deviations (in parentheses) are presented for each group, unless noted otherwise. ADHD-CT = attention-deficit/hyperactivity disorder, combined type; CPRS-R = Connors Parent Rating Scale–Revised; EL = emotional lability; SES = socioeconomic status.
CPRS-R Emotional Lability (EL) Scale parent ratings (t scores) differed between high-EL and low-EL groups (t36= 14.7, p < .0001) and between typically developing comparisons (TDC) and the high-EL group (t35= −14.8, p < .0001). Skewness = 0.82.
Hyperactivity-impulsivity (t scores) ratings differed between each of the ADHD groups and the comparison group (High EL vs. comparisons: t35 = −13.0, p < .0001 and Low EL vs. comparisons: t36= −8.8, p < .0001). No differences on hyperactivity scores were found between the high- and low-EL groups.