Table 1. Demographic and Clinical Characteristics of the codeine-containing cough syrups dependent (CCS-dependent) individuals and Control subjects.
| Characteristic | CCS-dependent individuals (n = 30) | Control subjects (n = 30) | Z Value | p value |
| Age (years) | 25.07 (3.08)a | 23.97(2.47) a | 2.706 | 0.133 |
| Gender (male:female) | 28:2 | 28:2 | - | 1.000 |
| Education (years) | 13.03 (2.76) a | 12.07 (3.42) a | 1.126 | 0.233 |
| Nicotine ((no. cigarette/day)) | 16.53 (9.61) a | 13.50(8.82) a | 0.036 | 0.208 |
| Cough syrups use (years) | 5.08 (range:1∼8) | N/Ab | - | - |
| Age of first use cough syrups | 19.93 (range:12∼30) | N/Ab | - | - |
| Mean dose (ml/d) | 487.33(range:60∼1800) | N/Ab | - | - |
| Head motion | ||||
| Shift | 12.32 E-2(1.64 E-2) | 12.19 E-2(1.42 E-2) | 1.372 | 0.354 |
| Rotation | 1.69 E-3(0.52 E-3) | 1.71 E-3(0.66 E-3) | −0.772 | 0.425 |
| Total BIS scores | 71.63(4.60) a | 57.13(5.18) a | 0.778 | 0.000
|
| Attentional impulsivity | 18.27(2.95) a | 15.57(1.63) a | 5.341 | 0.000
|
| Motor impulsivity | 30.50(2.74) a | 22.13(3.38) a | 2.727 | 0.000
|
| Non-plan impulsivity | 22.87(1.96) a | 19.63(2.71) a | 1.755 | 0.000
|
a
: means±standard deviations. b: N/A = not applicable. 
: p<0.05.