Table 1.
Demographics of subjects stratified per genotype, values are mean ± SD
| DRD2 genotype | COMT genotype | ||||||
|---|---|---|---|---|---|---|---|
| Measure | A2/A2 | A1 carriers | p value | MetMet | ValMet | ValVal | p value |
| N | 44 | 17 | 23 | 23 | 13 | ||
| Gender (M/F) | 36/8 | 13/4 | 0.64 | 16/7 | 19/4 | 13/0 | 0.08 |
| Age (years) | 22.1 ± 3.8 | 23.8 ± 5.3 | 0.17 | 23.1 ± 4.8 | 22.1 ± 3.0 | 23.1 ± 5.4 | 0.71 |
| Years of educationa | 14.2 ± 2.2 | 15.0 ± 1.8 | 0.20 | 14.6 ± 2.2 | 14.6 ± 1.9 | 14.1 ± 2.5 | 0.80 |
| Occasions of cocaine use (occasions per last year)b | 8.9 ± 4.7 | 15.2 ± 18.1 | 0.04* | 9.2 ± 4.7 | 9.5 ± 6.3 | 16.0 ± 20.0 | 0.13 |
| Estimated frequency of cannabis use (J/W) | 5.5 ± 4.9 | 8.0 ± 5.3 | 0.078 | 6.6 ± 4.8 | 6.4 ± 5.9 | 5.5 ± 4.7 | 0.83 |
aData is missing for one subject
bWhen one outlying participant was removed, the DRD2 genotype effect on occasions of cocaine use was no longer significant (p = 0.17)