Table 1.
Descriptive Characteristics and Psychiatric Diagnoses by ADHD and Control Groups (N = 368)
| Variable | ADHD Combined (n = 155) | ADHD Inattentive (n = 65) | ADHD Hyperactive (n = 18) | IHI Problems (n = 30) | Controla(n = 100) | Statistic (df) | p value |
|---|---|---|---|---|---|---|---|
| Gender (% male) | 77.3 | 63.1 | 88.9 | 66.7 | 78.0 | χ2(4) = 8.69 | 0.069 |
| Ethnicity (% Caucasian) | 90.3 | 90.8 | 100.0 | 96.7 | 93.9 | χ2(16) = 17.18 | 0.374 |
| Age (years) | 9.61 (2.87) | 11.94 (2.89) | 7.83 (3.82) | 12.10 (3.57) | 12.27 (3.26) | F(4,362) = 18.96 | <0.001 |
| Median household income | $50,000–75,000 | >$75,000 | $50,000–75,000 | $50,000–75,000 | $50,000–75,000 | F(4,360) = 4.14 | 0.004 |
| CD | 34.2 | 4.6 | 5.6 | 6.7 | 1.0 | χ2(4) = 63.59 | <0.001 |
| ODD | 60.6 | 63.1 | 66.7 | 46.7 | 10.0 | χ2(4) = 76.15 | <0.001 |
| Bipolar disorder | 9.0 | 4.6 | 5.6 | 13.3 | 0.0 | χ2(4) = 12.04 | 0.017 |
| Depressive disorder | 45.8 | 50.8 | 22.2 | 50.0 | 9.0 | χ2(4) = 17.18 | <0.001 |
| Anxiety disorder | 73.5 | 84.6 | 66.7 | 70.0 | 21.0 | χ2(4) = 93.65 | <0.001 |
Values denote means (standard deviations) unless otherwise indicated. The Brown–Forsythe statistic was reported for median household income. Psychiatric diagnoses are reported as the proportion (%) of subjects with a positive diagnosis.
a
9% of community controls met criteria for ADHD.
Abbreviations: ADHD = Attention-deficit/hyperactivity disorder; df = degrees of freedom; CD = conduct disorder; ODD = oppositional defiant disorder.