Table 6.
Distribution of ADHD subtypes according to age
| Age (years) | ADHD-I | ADHD-H | ADHD-C | Total | χ2 | P-value |
|---|---|---|---|---|---|---|
| 7 | 10 (45.46) | 1 (4.55) | 11 (50.00) | 22 (100) | 12.41 | 0.002 |
| 8 | 26 (66.67) | 4 (10.26) | 9 (23.08) | 39 (100) | 30.69 | <0.001 |
| 9 | 27 (61.36) | 6 (13.64) | 11 (25.00) | 44 (100) | 24.61 | <0.001 |
| 10 | 27 (81.82) | 2 (6.06) | 4 (12.12) | 33 (100) | 52.64 | <0.001 |
| 11 | 17 (68.00) | 1 (4.00) | 7 (28.00) | 25 (100) | 23.52 | <0.001 |
| 12 | 11 (91.67) | 0 (0) | 1 (8.33) | 12 (100) | 16.67 | <0.001 |
| Total | 118 (67.43) | 14 (8.00) | 43 (24.57) | 175 (100) | 148.13 | <0.001 |
Notes: Data are expressed as number (%). Age difference: ADHD-I: χ2=19.73, P=0.001; ADHD-H: χ2=7.41, P=0.097; ADHD-C: χ2=13.54, P=0.019; and total: χ2=28.59, P<0.001.
Abbreviations: ADHD, attention-deficit hyperactivity disorder; ADHD-H, attention deficit hyperactivity disorder, predominantly hyperactive type; ADHD-I, attention deficit hyperactivity disorder, predominantly inattentive type; ADHD-C, attention deficit hyperactivity disorder, predominantly combined type.