Table 2.
Effects of SM: sample characteristics
| ADHD-only (n = 62) | ADHD + SM (n = 62) | Control (n = 62) | p valuea | |
|---|---|---|---|---|
| FH of SUD (FH−/FH+) | 16/46 | 16/46 | 16/46 | 1.00 |
| Age (mean ± SD) | 18.14±2.51 | 18.78±2.76 | 17.1±2.63 | 0.002b |
| Gender (male/female) | 54/8 | 54/8 | 22/40 | <0.001b, c |
| IQd (mean ± SD) | 99.92±15.76 | 93.95±15.12 | 107.39±14.32 | <0.001b, c, e |
| Site (Nijmegen/Amsterdam) | 41/21 | 32/30 | 30/32 | 0.106 |
| DBD (yes/no) | 15/47 | 18/44 | 0/62 | <0.001b, c |
| ADHD medication (yes/no) | 38/24 | 26/36 | 0/62 | <0.001b, c |
| Conners' parents DSM-IV | ||||
| Inattention (mean ± SD) | 62.17±10.89 | 64.25±10.53 | 47.02±5.38 | <0.001b, c |
| Hyperactivity-impulsivity (mean ± SD) | 68.54±14.59 | 68.03±13.82 | 46.29±5.31 | <0.001b, c |
| Total (mean ± SD) | 66.67±13.67 | 68.19±12.69 | 46.21±5.28 | <0.001b, c |
| Conners' teacher/self DSM-IV | ||||
| Inattention (mean ± SD) | 64.72±11.03 | 67.98±12.11 | 46.73±7.61 | <0.001b, c |
| Hyperactivity-impulsivity (mean ± SD) | 58.83±12.75 | 58.22±12.77 | 44.88±8.06 | <0.001b, c |
| Total (mean ± SD) | 64.26±11.84 | 66.12±12.9 | 45.24±7.68 | <0.001b, c |
| K-SADS interview | ||||
| Inattention (mean ± SD) | 6.18±2.1 | 6.3±1.87 | − | 0.68 |
| Hyperactivity-impulsivity (mean ± SD) | 5.06±2.51 | 4.68±2.16 | − | 0.359 |
| CU traits | ||||
| Uncaring (mean ± SD) | 9.18±3.17 | 11.32±3.67 | 6.42±3.04 | <0.001b, c, e |
| Callousness (mean ± SD) | 6.47±3.06 | 7.55±3.57 | 5.26±2.59 | <0.001b |
| Unemotional(mean ± SD) | 7.06±3.54 | 7.81±2.91 | 6.32±2.49 | 0.025b |
| Total score | 24.53±7.77 | 29.02±7.99 | 19.37±5.95 | <0.001b, c, e |
SM, substance misuse; ADHD, attention-deficit/hyperactivity disorder; ADHD-only, ADHD without substance misuse; ADHD + SM, ADHD with substance misuse; FH, family history of SUD; SUD, substance use disorder; DBD, disruptive behavioral disorder (i.e., presence of oppositional defiant disorder or conduct disorder); CU traits, callous-unemotional traits.
Group differences were examined with one-way ANOVAs for age and IQ and with χ2 tests for FH, gender, site, DBD and ADHD medication.
Post hoc comparisons (corrected with the Bonferroni-Holm method) showed a difference between ADHD + SM and controls.
Post hoc comparisons (corrected with the Bonferroni-Holm method) showed a difference between ADHD-only and controls.
IQ level was estimated based on the cognitive performance in Block Design & Vocabulary tasks of Wechsler Intelligence Scale for Children (WISC) & Wechsler Adult Intelligence Scale (WAIS).
Post hoc comparisons (corrected with the Bonferroni-Holm method) showed a difference between ADHD-only and ADHD+SM.