Waziri R, Mott J, Wilcox J
J Affect Disord. 1985 Sep;9(2):175-80. doi: 10.1016/0165-0327(85)90098-9.
In a study of fasting plasma serine levels (PSL) previously shown to be a biological marker for psychosis, we found significantly higher (P = 0.0008) PSL in 18 psychotic depressives when compared to 22 nonpsychotic depressives. Similarly the activity of the enzyme serine hydroxymethyltransferase (SHMT) which cleaves serine to glycine, was significantly lower (P less than 0.0001) in psychotics than in nonpsychotics. The difference between psychotic and nonpsychotic depressives were not attributable to age, sex or drug intake. This finding is in support of the hypothesis that these two types of depressions are qualitatively distinct from each other.
在一项对空腹血浆丝氨酸水平（PSL）的研究中，此前已证明该水平是精神病的生物学标志物，我们发现，与22名非精神病性抑郁症患者相比，18名精神病性抑郁症患者的PSL显著更高（P = 0.0008）。同样，将丝氨酸裂解为甘氨酸的丝氨酸羟甲基转移酶（SHMT）的活性，在精神病患者中显著低于非精神病患者（P小于0.0001）。精神病性和非精神病性抑郁症患者之间的差异并非归因于年龄、性别或药物摄入。这一发现支持了这两种抑郁症在性质上彼此不同的假设。
