| Forced entry model | Backward elimination model | ||||
---|---|---|---|---|---|---|
β ± SD | p value | VIF | β ± SD | p value | VIF | |
Normal control | ||||||
 Sex | −0.33 ± 0.23 | 0.17 | 1.90 | −0.33 ± 0.15 | 0.04 | 1.18 |
 Age | 0.55 ± 0.20 | 0.01 | 1.51 | 0.53 ± 0.15 | <0.001 | 1.09 |
 Smoking status | −0.05 ± 0.21 | 0.92 | 1.55 |  |  |  |
 Vitamin B12 | −0.11 ± 0.28 | 0.70 | 2.76 |  |  |  |
 Folate | −0.08 ± 0.24 | 0.75 | 2.06 |  |  |  |
 Homocysteine | −0.08 ± 0.21 | 0.71 | 1.55 |  |  |  |
 l-serine | 0.40 ± 0.28 | 0.17 | 2.79 | 0.43 ± 0.15 | 0.008 | 1.13 |
 d-serine | −0.03 ± 0.29 | 0.92 | 3.06 |  |  |  |
 Glycine | 0.02 ± 0.28 | 0.94 | 1.91 |  |  |  |
 Genotype131 | −0.03 ± 0.19 | 0.89 | 1.25 |  |  |  |
 Genotype133 | 0.08 ± 0.25 | 0.75 | 2.37 |  |  |  |
Patients with schizophrenia | ||||||
 Sex | −0.06 ± 0.28 | 0.83 | 2.71 |  |  |  |
 Age | 0.21 ± 0.37 | 0.57 | 4.76 |  |  |  |
 Duration of illness | −0.02 ± 0.32 | 0.95 | 3.32 |  |  |  |
 Smoking status | 0.12 ± 0.25 | 0.63 | 2.19 |  |  |  |
 CP equivalent dose | −0.01 ± 0.28 | 0.95 | 1.53 |  |  |  |
 Vitamin B12 | 0.06 ± 0.22 | 0.74 | 1.29 |  |  |  |
 Folate | −0.11 ± 0.21 | 0.61 | 1.64 |  |  |  |
 Homocysteine | −0.29 ± 0.23 | 0.23 | 1.93 | −0.35 ± 0.16 | 0.14 | 1.18 |
 l-serine | 0.15 ± 0.26 | 0.55 | 2.31 |  |  |  |
 d-serine | −0.13 ± 0.27 | 0.63 | 2.58 |  |  |  |
 Glycine | 0.10 ± 0.26 | 0.67 | 2.05 |  |  |  |
 Genotype131 | 0.32 ± 0.24 | 0.20 | 2.07 | 0.35 ± 0.16 | 0.14 | 1.36 |
 Genotype133 | 0.21 ± 0.28 | 0.46 | 2.77 | 0.27 ± 0.18 | 0.14 | 1.18 |