Table 1. Participant characteristics.
|
Expressed emotion selection |
Peer affiliation selection |
|||||
|---|---|---|---|---|---|---|
| N | M | s.d. | N | M | s.d. | |
| Number of families | 150 | 261 | ||||
| ADHD diagnosis | 153 | 79% | 166 | 39% | ||
| Inattentive subtype | 68 | 35% | 74 | 17% | ||
| Hyperactive–impulsive subtype | 18 | 9% | 25 | 6% | ||
| Combined subtype | 67 | 35% | 67 | 16% | ||
| Subthreshold ADHD | 19 | 10% | 43 | 10% | ||
| Unaffected | 21 | 11% | 220 | 51% | ||
| ADHD severity (CPRS) | 191 | 20.94 | 12.18 | 418 | 12.08 | 12.25 |
| ODD diagnosis | 46 | 24% | 50 | 12% | ||
| CD diagnosis | 11 | 6% | 11 | 6% | ||
| History of stimulant use | 136 | 70% | 145 | 34% | ||
| Male | 127 | 66% | 237 | 55% | ||
| Collection site (Amsterdam) | 80 | 42% | 216 | 50% | ||
| Age | 193 | 17.15 | 3.24 | 429 | 17.48 | 3.52 |
| Estimated IQ | 193 | 97.54 | 14.85 | 426 | 101.62 | 12.25 |
| Maternal warmth/positive peer affiliation | 193 | 1.64 | 0.89 | 429 | 22.52 | 3.58 |
| Maternal criticism/deviant peer affiliation | 193 | 1.65 | 0.92 | 429 | 15.01 | 4.44 |
| MRT reward condition (ms) | 193 | 298.81 | 39.44 | 429 | 298.25 | 36.73 |
| MRT non-reward condition (ms) | 193 | 332.05 | 50.01 | 429 | 329.48 | 47.62 |
| Variability reward condition (ms) | 193 | 0.21 | 0.14 | 429 | 0.19 | 0.11 |
| Variability non-reward condition (ms) | 193 | 0.25 | 0.15 | 429 | 0.24 | 0.15 |
| Bold response reward anticipation | ||||||
| VS | 167 | 196.90 | 841.49 | 375 | 267.14 | 828.11 |
| vmPFC | 167 | −508.21 | 1882.21 | 375 | −412.53 | 2132.62 |
| Bold response reward receipt | ||||||
| VS | 167 | 604.36 | 1542.24 | 375 | 408.06 | 1540.83 |
| vmPFC | 167 | 1722.58 | 3714.42 | 375 | 1498.62 | 4225.33 |
| DAT1 | 186 | 407 | ||||
| 9-repeat present | 62a | 33% | 150b | 37% | ||
| 9-repeat absentc | 124 | 67% | 257 | 63% | ||
| 5-HTT | 190 | 416 | ||||
| Short allele present | 123d | 65% | 269e | 65% | ||
| Short allele absent | 67 | 35% | 147 | 35% | ||
| DRD4 | 190 | 417 | ||||
| 7-repeat present | 64 | 34% | 143 | 34% | ||
| 7-repeat absent | 126 | 66% | 274 | 66% | ||
Abbreviations: ADHD, attention-deficit/hyperactivity disorder; CD, conduct disorder; CPRS, Conners Parent Raring Scale; IQ, intelligence quotient; MRT, mean reaction time; ODD, oppositional defiance disorder; vmPFC, ventral medial prefrontal cortex; VS, ventral striatum.
ODD and CD diagnoses were based on Kiddie-Schedule for Affective Disorders and Schizophrenia (K-SADS) structured psychiatric interviews.47
Estimated IQ was based on two subtests of the Wechsler Intelligence Scale for Children (WISC)/ Wechsler Adult Intelligence Scale (WAIS-III): Vocabulary and Block Design.48, 49
a
N=12 (7%) with two 9-repeats.
b
N=20 (5%) with two 9-repeats.
c
10/10 genotype.
d
N=28 (15%) with two short alleles.
e
N=59 (14%) with two short alleles.