Table 2.
Results of multiple linear regressions examining the interaction of methamphetamine (METH) status and COMT genotype on dopamine (DA), homovanillic acid (HVA) and HVA/DA ratios
| Outcome: CSF DA (log) | beta (SE) | 95% CI | p |
|---|---|---|---|
| METH+ (vs. METH−)a | −1.10 (0.55) | −2.20, 0.00 | 0.050 |
| Val/Met (vs. Met/Met)b | −0.89 (0.51) | −1.90, 0.12 | 0.082 |
| Val/Val (vs. Met/Met)b | −1.18 (0.58) | −2.34, −0.02 | 0.046 |
| METH+ x Val /Met | 1.56 (0.67) | 0.24, 2.89 | 0.021 |
| METH+ x Val/ Val | 1.09 (0.76) | −0.42, 2.59 | 0.154 |
| Outcome: CSF HVA (log) | beta (SE) | 95% CI | p |
| METH+ (vs. METH−)a | 0.13 (0.47) | −0.81, 1.07 | 0.778 |
| Val/Met (vs. Met/Met)b | −0.46 (0.44) | −1.33, 0.40 | 0.291 |
| Val/Val (vs. Met/Met)b | −0.35 (0.50) | −1.34, 0.64 | 0.482 |
| METH+ x Val /Met | −0.06 (0.57) | −1.19, 1.08 | 0.918 |
| METH+ x Val/ Val | −0.59 (0.65) | −1.88, 0.70 | 0.366 |
| Outcome: CSF HVA/DA (log) | beta (SE) | 95% CI | p |
| METH+ (vs. METH−)a | 1.24 (0.54) | 0.16, 2.32 | 0.025 |
| Val/Met (vs. Met/Met)b | 0.43 (0.50) | −0.56, 1.42 | 0.391 |
| Val/Val (vs. Met/Met)b | 0.83 (0.57) | −0.31, 1.97 | 0.152 |
| METH+ x Val /Met | −1.62 (0.66) | −2.93, −0.32 | 0.015 |
| METH+ x Val/ Val | −1.68 (0.75) | −3.15, −0.20 | 0.026 |
a
Represents effect of METH in Met/Met individuals only (reference group)
b
Represents effect of COMT in METH- individuals only (reference group)