Characteristics of included studies
| Study | ERP | Diagnosis | Comorbidity* | Experimental paradigm | Sample size, n | % Male | Mean age ± SD, yr | ||
|---|---|---|---|---|---|---|---|---|---|
| Ext | Con | Ext | Con | ||||||
| Albrecht et al. (41) (2008) | Both | Child ADHD | Yes, mix | Flanker | 68 | 22 | 100 | 11.3 ± 1.6 | 11.2 ± 1.7 |
| Balogh et al. (69) (2017) | Both | Adult ADHD | Yes, int | Go/no-go | 26 | 14 | 78 | 26.7 ± 5.7 | 31.5 ± 11.4 |
| Brazil et al. (70) (2009) | Both | Other: violent offenders | No | Flanker | 16 | 18 | 100 | 39 ± 9.5 | 37 ± 6.4 |
| Chang et al. (71) (2009) | Both | Adult ADHD | Yes, mix | Flanker | 36 | 32 | 50 | 23.7 ± 3.7 | 23.7 ± 3.7 |
| Chen et al. (72) (2013) | ERN | Clinical addiction | No | Flanker | 20 | 15 | 100 | 37.1 ± 9.5 | 32.5 ± 10 |
| Czobor et al. (73) (2017) | Pe | Adult ADHD | No | Go/no-go | 22 | 29 | 71 | 30.6 ± 9.7 | 30.1 ± 9 |
| Franken et al. (42) (2007) | Both | Clinical addiction | No | Flanker | 14 | 13 | 78 | 38.1 ± 10.2 | 32 ± 13.8 |
| Franken et al. (74) (2010) | Pe | Subclinical addiction | No | Flanker | 23 | 28 | 48 | 21.7 ± 2.7 | 21.3 ± 2.8 |
| Franken et al. (28) (2017) | Both | Subclinical addiction | No | Flanker | 48 | 49 | 49 | 23.4 ± 10 | 11.9 ± 8.5 |
| Franken et al. (75) (2018) | Both | Subclinical addiction | No | Flanker | 34 | 34 | 12 | 19.9 ± 1.7 | 20.8 ± 3 |
| Groom et al. (76) (2010) | Both | Child ADHD | Yes, ext | Go/no-go | 23 | 19 | 74 | 16.2 ± 0.3 | 16.1 ± 2 |
| Groom et al. (32) (2013) | ERN | Child ADHD | Yes, mix | Go/no-go | 28 | 28 | 96 | 12.5 ± 1.8 | 12.5 ± 1.8 |
| Hermann et al. (77) (2010a) | Pe | Adult ADHD | No | Flanker | 17 | 9 | 50 | 25.2 ± 4.4 | 24.2 ± 3.1 |
| Hermann et al. (77) (2010b) | Pe | Adult ADHD | No | Flanker | 17 | 9 | 56 | 40.0 ± 6.8 | 39.7 ± 6.6 |
| Jonkman et al. (78) (2007) | Pe | Child ADHD | No | Flanker | 10 | 10 | NA | 9.5 ± 2.1 | 10.76 ± 1.2 |
| Littel et al. (79) (2012) | Both | Subclinical addiction | No | Go/no-go | 25 | 27 | 63 | 20.5 ± 3 | 21.42 ± 2.6 |
| Luijten et al. (43) (2011) | Both | Subclinical addiction | No | Flanker | 13 | 14 | 70 | 20.7 ± 1.3 | 21.4 ± 2.6 |
| Maij et al. (80) (2017a) | Both | Clinical addiction | Yes, ext | Flanker | 35 | 39 | 76 | 21.7 ± 2.1 | 22.1 ± 2.1 |
| Maij et al. (80) (2017b) | Both | Clinical addiction | Yes, ext | Flanker | 38 | 39 | 68 | 21.4 ± 2.5 | 22.1 ± 2.1 |
| Marhe et al. (81) (2013) | Both | Clinical addiction | No | Flanker | 49 | 23 | 84 | 39.6 ± 8.4 | 39.9 ± 9.4 |
| Marquardt et al. (82) (2018) | Both | Adult ADHD | Yes, mix | Flanker | 27 | 28 | 51 | 35.3 ± 8.8 | 33.4 ± 7 |
| McLoughlin et al. (83) (2009a) | Both | Adult ADHD | No | Flanker | 21 | 20 | 100 | 32.5 ± 5.8 | 30 ± 6.5 |
| McLoughlin et al. (83) (2009b) | Both | Adult ADHD | No | Flanker | 20 | 20 | 100 | 45.9 ± 4.2 | 30 ± 6.5 |
| Michelini et al. (84) (2016a) | Both | Adult ADHD | Yes | Flanker | 87 | 169 | 67 | 18.3 ± 3 | 18.8 ± 2.2 |
| Michelini et al. (84) (2016b) | Both | Adult ADHD | Yes | Flanker | 23 | 169 | 79 | 18.3 ± 3 | 18.8 ± 2.2 |
| Morie et al. (85) (2014) | Both | Clinical addiction | Yes, ext | Go/no-go | 23 | 27 | 72 | 44 ± 6.6 | 4.1 ± 8.5 |
| Munro et al. (86) (2007) | Both | Other: violent offenders | No | Flanker | 15 | 15 | 100 | 45.9 ± 13.6 | 46.6 ± 6.9 |
| Rass et al. (44) (2014a) | Both | Clinical addiction | No | Flanker | 22 | 15 | 52 | 27.2 ± 5.3 | 25.2 ± 4.3 |
| Rass et al. (44) (2014b) | Both | Subclinical addiction | No | Flanker | 31 | 15 | 43 | 23.9 ± 4.4 | 25.2 ± 4.3 |
| Sokhadze et al. (87) (2008) | ERN | Clinical addiction | Yes, int | Flanker | 19 | 15 | 56 | 42.1 ± 5.5 | 37 ± 9.4 |
| Vilà-Balló et al. (88) (2014) | Both | Other: violent offenders | No | Flanker | 17 | 17 | 100 | 18.3 ± 0.3 | 18.6 ± 0.3 |
| Wiersema et al. (30) (2005) | Pe | Child ADHD | Yes, ext | Go/no-go | 22 | 15 | 65 | 10.3 ± 1.6 | 10.2 ± 2 |
| Wiersema et al. (26) (2009) | Pe | Child ADHD | Yes, mix | Go/no-go | 23 | 19 | 57 | 29.3 ± 11 | 30.9 ± 11 |
| Wild-Wall et al. (45) (2009) | Both | Child ADHD | Yes, int | Flanker | 15 | 12 | 71 | 13.0 ± 1.6 | 13.2 ± 1.5 |
| Xue et al. (89) (2017) | Pe | Other: aggression | No | Go/no-go | 13 | 14 | 44 | 21.3 ± 0.9 | 21.3 ± 1.3 |
| Zhang et al. (90) (2009) | Pe | Child ADHD | No | Go/no-go | 16 | 16 | NA | 7.5 ± 1.4 | 7.6 ± 1.8 |
| Zijlmans et al. (91) (2019) | Both | Other: multi-problem | Yes, ext | Flanker | 119 | 26 | 100 | 22.5 ± 2.4 | 23.1 ± 2.6 |
ADHD = attention-deficit/hyperactivity disorder; con = control; ERN = error-related negativity; ERP = event-related potential; ext = externalizing; int = internalizing, mix = both externalizing and internalizing; NA = not applicable (not measured or unknown); Pe = error positivity; SD = standard deviation.
↵* Comorbid diagnosis or symptoms.