Table 1.
Overview of included study data, participant characteristics, and outcome.
| Study | Subjects | Sample | Assay | [OT] | Unit | Results | ||
|---|---|---|---|---|---|---|---|---|
| ASD | NT | ASD | NT | |||||
| OT levels in children (13) | ||||||||
| 1. Abdulamir et al. (2016) | n = 60 (60 M) Age (y): 7.28 ± 2.89 DSM-5 |
n = 26 (26 M) Age (y): 6.92 ± 2.59 |
Plasma | ELISA | 44.72 ± 36.1 |
102.1 ± 34.31 |
μIU/mL | Lower OT in ASD (p < 0.001) |
| 2. Alabdali et al. (2014) | n = 50 (50 M) Age (y): 7.0 ± 2.34 DSM-IV; CARS, SRS |
n = 30 (30 M) Age (y): 7.2 ± 2.14 |
Plasma | ELISA | 71.71 ± 18.09 |
139.22 ± 36.62 | μIU/mL | Lower OT in ASD (p = 0.001) |
| 3. Feldman et al. (2014) | n = 40 (34 M/6 F) Age (m): 63.38 ± 12.35 DSM-5; ADOS-2 |
n = 40 Age (m): 53.56 ± 13.83 |
Saliva | ELISA | 4.25 ± 0.66 | 6.89 ± 1.03 | pg/mL | Lower OT in ASD (p < 0.05) |
| 4. Fujisawa et al. (2014) | n = 15 (12 M/3 F) Age (m): 57.9 ± 13.6 DSM-5; DQ, PARS, SDQ |
n = 58 (27 M/31 F) Age (m): 48.1 ± 22.7 |
Saliva | ELISA | 39.33 ± 23.52 M: 40.3 ± 23.52 F: 35.7 ± 20.11 |
44.5 ± 24.89 M: 45.7 ± 29.78 F: 43.4 ± 20.15 |
pg/mL | No significant differences between groups (p = 0.449) |
| 5. Husarova et al. (2016) | n = 19 (19 M) Age (m): 56.7 ± 25.4 ICD-10; CARS, ADI |
n = 44 (44 M) Age (m): 58.9 ± 23.0 |
Plasma | ELISA | 124.10 ± 90.59 | 267.77 ± 212.37 | pg/mL | Lower OT in ASD (p = 0.0004) |
| 6. Jacobson et al. (2014) | n = 37 (25 M/12 F) Age (y): 4.73 ± 0.61 DSM-IV-TR; ADI-R, ADOS |
n = 41 (24 M/17 F) Age (y): 4.85 ± 0.61 |
Plasma | ELISA | M: 24.41 ± 7.45 F: 23.04 ± 6.97 |
M: 18,58 + 6.98 F: 22.59 + 8.82 |
pg/mL | Higher OT in male ASD only (p = 0.022) |
| 7. Lakatosova et al. (2015) | n = 104 (80 M/24 F) Age (y): 7 ± 5.5 DSM-IV |
n = 128 (103 M/25 F) Age (y): 10.5 ± 7 |
Plasma | ELISA | M: 208.1 ± 238.63F: 282.9 ± 318.92 | M: 281.7 ± 200.85F: 340.7 ± 340.70 | pg/mL | Lower OT in male ASD only (M: p = 0.0248; F: p = 0.5058) |
| 8. Mariscal et al. (2019) | n = 34 (28 M/6 F) Age (y): 9.26 ± 0.37 DSM-IV-TR/DSM-V; ADI-R, ADOS |
n = 30 (21 M/9 F) Age (y): 8.80 ± 0.40 |
Plasma | ELISA | 8.62 ± 5.36 | 10.54 ± 5.37 | pg/mL | No significant differences between groups (p = 0.1564) |
| 9. Modahl et al. (1998) | n = 29 (29 M) Age (y): 8.1 + 1.7 DSM-IV |
n = 30 (30 M) Age (y): 8.8 + 1.8 |
Plasma | RIA | 0.64 ± 0.58 | 1.16 ± 0.77 | pg/mL | Lower OT in ASD (p < 0.004) |
| 10. Tanaka et al. (2020) | n = 12 (11 M/1 F) Age (m): 135 ± 16.7 DSM-IV-TR, DSM-V; CARS, ADOS, DISCO |
n = 8 (4 M/4 F) Age (m): 107 ± 6.9 |
Saliva | ELISA | 167.9 ± 62.01 | 161.5 ± 54.87 | pg/mL | No significant difference between groups |
| 11. Taurines et al. (2014) | n = 19 (19 M) Age (y): 10.7 ± 3.8 ICD-10; ADI-R, ADOS |
n = 17 (17 M) Age (y): 13.6 ± 2.1 |
Plasma | RIA | 19.6 ± 7.1 | 14.4 ± 9.6 | pg/mL | No significant difference between groups (p = 0.132) |
| 12. Yang et al. (2015) | n = 43 (35 M/8 F) Age (y): 7.51 ± 1.47 DSM-5; CARS |
n = 40 (30 M/10 F) Age (y): 7.83 ± 1.63 |
Plasma | ELISA | 116.47 ± 41.57 | 141.05 ± 51.61 | pg/mL | Lower OT in ASD (p = 0.022) |
| 13. Zhang et al. (2016) | n = 84 (71 M/13 F) Age (y): 3.95 ± 1.26 DSM-IV-TR; CARS |
n = 85 (71 M/14 F) Age (y): 4.80 ± 1.22 |
Plasma | ELISA | 20.05 ± 13.88 | 25.76 ± 15.30 | pg/mL | Lower OT in ASD (p = 0.028) |
| OT levels in adolescents (2) | ||||||||
| 14. Bakker-Huvenaars et al. (2020) | n = 49 (49 M) Age (y): 15.0 ± 2.1 DSM-5; DISC-IV |
n = 28 (28 M) Age (y): 15.9 ± 1.8 |
Saliva | RIA | −0.22 ± 0.89 | 0.49 ± 0.97 | z-score | Lower OT in ASD (p = 0.002) |
| 15. Miller et al. (2013) | n = 40 (21 M/19 F) Age (y): M: 12.24 ± 3.56; F: 11.79 ± 3.43 DSM-IV-TR; ADOS |
n = 35 (19 M/16 F) Age (y): M: 11.74 ± 2.49; F: 12.94 ± 3.19 |
Plasma | ELISA | M: 357.12 ± 126.05F: 525.23 ± 325.75 | M: 361.52 ± 315.26F: 434.33 ± 332.27 | pg/mL | No significant differences between groups (p = 0.270) |
| OT levels in adults (3) | ||||||||
| 16. Althaus et al. (2016) | n = 31 (31 M) Age (y): 22.67 ± 4.22 DSM-IV-TR; ADOS, |
n = 30 (30 M) Age (y): 22.67 ± 4.22 |
Plasma | RIA | 1.34 ± 1.05 | 0.67 ± 0.77 | pmol/L | Higher OT in ASD (p = 0.006) |
| 17. Fujioka et al. (2020) | n = 17 (17 M) Age (y): 27.4 ± 7.2 DSM-IV; DISCO |
n = 24 (24 M) Age (y): 29.0 ± 9.8 |
Saliva | ELISA | 36.2 ± 13.2 | 43.6 ± 17.0 | pg/mL | No significant difference between groups (p = 0.154) |
| 18. Procyshyn et al. (2020) | n = 16 (16 F) Age (y): 29.9 ± 8.4 DSM-IV |
n = 29 (29 F) Age (y): 27.2 ± 8.1 |
Saliva | ELISA | 3.1 ± 0.5 | 2.8 ± 0.6 | pg/mL | No significant difference between groups (p = 0.064) |
OT = oxytocin (mean ± SD), ASD = autism spectrum disorder, NT = neurotypical, M = male, F = female, y = years, m = months, ELISA = enzyme-linked immunosorbent assay, RIA = radioimmunoassay. DSM-IV or DSM-5 Diagnostic and Statistical Manual of Mental Disorders Version IV or 5. ICD-10 = International Classification of Diseases Version 10. When applicable: confirmation of the ASD diagnosis using ADOS = Autism Diagnostic Observation Schedule or ADI(-R) = Autism Diagnostic Interview (-Revised) or CARS = Childhood Autism Rating Scale or DISCO = Diagnostic Interview for Social and Communication Disorders or DISC-IV Diagnostic Interview Schedule for Children Version IV3.2.