Table 2.
Demographic, Perinatal and Clinical Characteristics of ADHD Sample at Baseline
| Not treated with stimulants (n=2818)a | Treated with stimulants (n=5482)a | |||
|---|---|---|---|---|
| Variable | Mean (SD) | n (%) | Mean (SD) | n (%) |
| ADHD and treatment | ||||
| Age at ADHD diagnosis | 10.01 (3.22) | 10.03 (3.00) | ||
| Age at initiation of stimulant treatment | - | 10.48 (2.88) | ||
| Duration of stimulant treatment, years | - | 2.45 (2.11) | ||
| Childb | ||||
| 5 min Apgar score | 9.74 (1.17) | 9.76 (1.07) | ||
| Gestation length (weeks) | 39.25 (2.40) | 39.29 (2.28) | ||
| Gender (male) | 2203 (78.2%) | 4511 (82.3%) | ||
| Birth weight <1500 g | 50 (1.9%) | 68 (1.3%) | ||
| Birth weight 1500–2500 g | 161 (6.0%) | 326 (6.2%) | ||
| Birth weight >2500 g | 2452 (92.1%) | 4831 (92,5%) | ||
| Complications at birth | 792 (28.1%) | 1634 (29.8%) | ||
| Congenital heart disease at birth (Q20–28) | 60 (2.1%) | 93 (1.7%) | ||
| Cardiovascular disease before age 5 | 40 (1.4%) | 69 (1.3%) | ||
| Fragile X syndrome | 0 (0.0%) | 2 (0.0%) | ||
| Down syndrome | 5 (0.2%) | 2 (0.0%) | ||
| Diabetes | 1 (0.0%) | 3 (0.1%) | ||
| Neuroleptic treatment before age 5 | 0 (0.0%) | 3 (0.1%) | ||
| Heart medication before age 5 | 15 (0.5%) | 6 (0.1%) | ||
| Comorbid psychiatric condition | 1750 (62.1%) | 3450 (62.9%) | ||
| Affective disorder and anxiety | 275 (9.8%) | 459 (8.4%) | ||
| Number of psychiatric diagnoses | 2.19 (1.33) | 2.17 (1.28) | ||
| Number of injuries before age 5 | 1.01 (1.44) | 1.15 (1.58) | ||
| Number of hospital contacts before age 5 | 4.95 (4.97) | 4.99 (5.18) | ||
| Motherb | ||||
| Age, mean (SD) | 32.13 (5.21) | 31.79 (5.03) | ||
| Length of education (years) | 11.52 (2.37) | 11.52 (2.35) | ||
| Income (1,000 $/year 2004) | 38.3 (16.0) | 39.3 (15.4) | ||
| Married/cohabiting with the child's father | 1698 (61.9%) | 3266 (61.1%) | ||
| High school or less | 1297 (48.3%) | 2502 (47.5%) | ||
| Unemployed <13 weeks | 2237 (81.6%) | 4,395 (82.2) | ||
| Unemployed 13–26 weeks | 268 (9.8%) | 508 (9.5%) | ||
| Unemployed >26 weeks | 237 (8.6%) | 441 (8.3%) | ||
| Employed in November | 1707 (62.3%) | 3350 (66.1%) | ||
| Psychiatric diagnosis | 347 (12.3%) | 623 (11.4%) | ||
| Cardiovascular disease | 171 (6.1%) | 330 (6.0%) | ||
| Respiratory disease | 565 (20.1%) | 1157 (21.1%) | ||
| Smoking during pregnancy | 299 (12.7%) | 558 (12.2%) | ||
| Heart medication | 257 (9.1%) | 444 (8.1%) | ||
| Diabetes | 30 (1.1%) | 53 (1.0%) | ||
| Fatherb | ||||
| Age, mean (SD) | 35.10 (6.33) | 34.81 (6.01) | ||
| Length of education (years) | 11.47 (2.44) | 11.35 (2.38) | ||
| Income (1,000 $/year 2004) | 57.3 (33.2) | 58.0 (33.9) | ||
| High school or less | 1032 (41.4%) | 2069 (42.4%) | ||
| Unemployed <13 weeks | 2271 (88.4%) | 4472 (89.0%) | ||
| Unemployed 13–26 weeks | 152 (5.9%) | 267 (5.3%) | ||
| Unemployed >26 weeks | 146 (5.7%) | 286 (5.7%) | ||
| Employed in November | 2151 (83.7%) | 4291 (85.4%) | ||
| Psychiatric diagnosis | 279 (10.5%) | 546 (10.6%) | ||
| Cardiovascular disease | 170 (6.4%) | 330 (6.4%) | ||
| Respiratory disease | 427 (16.0%) | 816 (15.8%) | ||
| Heart medication | 121 (4.5%) | 249 (4.8%) | ||
| Diabetes | 28 (1.1%) | 42 (0.8%) | ||
Bold indicates a significant difference between the never and ever stimulant group at the 5% level.
a
For some baseline variables missing data.
b
Covariates measured when the child was 4 years of age, unless otherwise specified.
ADHD, attention-deficit/hyperactivity disorder.