TABLE 1.
Group differences on sociodemographic characteristics and internet use disorder (IUD) attributes.
| Variables | IUD patients | Healthy controls | Other mental disorders | p value | Effect size | |||
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| (EG1+EG2) | (CG1) | (CG2) | ||||||
| n = 60 | n = 55 | n = 34 | ||||||
| Age (M, SD) | 25.07 | 5.76 | 24.38 | 4.05 | 27.03 | 5.41 | 0.06 | η2 = 0.038 |
| BMI (kg/m2) | 26.92 | 5.83 | 24.37 | 4.06 | 27.17 | 7.34 | 0.023 | η2 = 0.037 |
| Marital status (n, % within each group) | <0.001b | φ = 0.368 | ||||||
| Partnership | 13 | 21.70% | 33 | 60.00% | 9 | 26.50% | ||
| Single | 47 | 78.30% | 22 | 40.00% | 25 | 73.50% | ||
| Education (n, % within each group) | <0.026b | φ = 0.221 | ||||||
| High school graduate | 33 | 55.00% | 42 | 76.40% | 18 | 52.90% | ||
| Less than high school | 27 | 45.00% | 13 | 23.60% | 16 | 47.10% | ||
| Employment (n, % within each group) | <0.001b | φ = 0.434 | ||||||
| Currently in training/university | 25 | 41.70% | 25 | 45.50% | 7 | 20.60% | ||
| Completed vocational training | 9 | 15.00% | 7 | 12.70% | 13 | 38.30% | ||
| University degree | 4 | 6.70% | 14 | 25.40% | 6 | 17.60% | ||
| No vocational training | 22 | 36.60% | 7 | 12.70% | 8 | 23.50% | ||
| Others | 0 | 0% | 2 | 3.70% | 0 | 0% | ||
| Time spent on the internet (M, SD) | ||||||||
| Weekdays (h/d) | 6.15 | 3.47 | 2.46 | 1.8 | 3.35 | 2.38 | <0.001c | η2 = 0.281 |
| At the weekend (h/d) | 8.19 | 4.35 | 3.38 | 2.76 | 4.27 | 2.98 | <0.001c | η2 = 0.287 |
| Average use/day (h/d) | 6.74 | 3.54 | 2.72 | 2.03 | 3.62 | 2.49 | <0.001c | η2 = 0.300 |
| Total time of use per week (h/w) | 47.15 | 24.79 | 19.09 | 14.19 | 25.32 | 17.49 | <0.001c | η2 = 0.300 |
| IUD subgroups (n, %) | ||||||||
| Gaming | 46 | 76.70% | – | – | – | – | ||
| Cybersex/pornography | 9 | 15.00% | – | – | – | – | ||
| Others/mixed IUD | 5 | 8.30% | – | – | – | – | ||
| s-IAT score (M, SD) | 37.2 | 10.09 | 17.42 | 4.62 | 20.64 | 6.75 | <0.001c | η2 = 0.591 |
| Type and frequencies of (comorbid) mental disorders (n, % within the group)a | ||||||||
| Internet Use Disorder | 60 | 100% | – | – | 0 | 0% | ||
| Depressive disorders | 19 | 31.70% | – | – | 22 | 64.7%% | 0.002 | φ = 0.320 |
| Panic disorder | 3 | 5.00% | – | – | 2 | 5.90% | 0.855 | φ = 0.019 |
| Agoraphobia | 7 | 11.70% | – | – | 3 | 8.80% | 0.668 | φ = 0.044 |
| Social phobia | 14 | 23.30% | – | – | 2 | 5.9%% | 0.031 | φ = 0.223 |
| Generalized anxiety disorder | 2 | 3.30% | – | – | 3 | 8.80% | 0.254 | φ = 0.118 |
| Obsessive-compulsive disorder | 1 | 1.70% | – | – | 0 | 0% | 0.449 | φ = 0.078 |
| Anorexia nervosa | 0 | 0%% | – | – | 3 | 8.8%% | 0.019 | φ = 0.241 |
| Others | 1 | 1.7%% | 7 | 20.0%% | 0.002 | φ = 0.318 | ||
| Mean number of mental disorders incl. IUD | 1.82 | 1.06 | – | – | 1.43 | 0.85 | 0.031 | d = 0.99 |
One missing value in the group of IUD patients regarding the time of use.
aIn the IUD group, only n = 29 patients showed comorbid mental disorders.
bPost-hoc tests of Chi2 analyses were compared by examining the adjusted residuals. Bonferroni correction for repeated testing was used.
cPost-hoc tests of ANOVAs were conducted using Bonferroni correction.