Toxoplasma gondii (T. gondii) IgG seropositivity and serointensity have been previously associated with suicidal self-directed violence (SSDV). Although associations with unipolar depression have also been investigated, the results have been inconsistent, possibly as a consequence of high heterogeneity. We have now studied this association in a more homogeneous population, [that is (i.e.) Old Order Amish (OOA)] with previously reported high T. gondii seroprevalence. In 306 OOA with a mean age of 46.1±16.7 years, including 191 (62.4%) women in the Amish Wellness Study, we obtained both T. gondii IgG titers (by enzyme-linked immunosorbent assay [ELISA]), and depression screening questionnaires (Patient Health Questionnaire [PHQ-9] [n=280] and PHQ-2 [n=26]). Associations between T. gondii IgG and dysphoria/hopelessness and anhedonia scores on depression screening questionnaires were analyzed using multivariable linear methods with adjustment for age and sex. Serointensity was associated with both current dysphoria/hopelessness (p=0.045) and current combined anhedonia and dysphoria/hopelessness (p=0.043), while associations with simple anhedonia and past/lifelong (rather than current) phenotypes were not significant. These results indicate the need for larger longitudinal studies to corroborate the association between dysphoria/hopelessness and T. gondii IgG-titers. Current hopelessness is a known risk factor for SSDV which responds particularly well to cognitive behavioral therapy, and may be a focused treatment target for T. gondii-positive individuals at high-risk for SSDV.

中文翻译：

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弓形虫 IgG 血清强度与旧秩序阿米什人当前烦躁/绝望评分之间的正相关：一项初步研究

弓形虫(刚地弓形虫) IgG 血清阳性和血清强度以前与自杀性自我导向暴力 (SSDV) 相关。尽管还研究了与单相抑郁症的关联，但结果不一致，可能是高度异质性的结果。我们现在已经在更同质的人群中研究了这种关联，[即（即）旧秩序阿米什人（OOA）]，先前报道的高刚地弓形虫血清阳性率。在平均年龄为 46.1±16.7 岁的 306 名 OOA 中，包括阿米什健康研究中的 191 名 (62.4%) 女性，我们同时获得了刚地弓形虫IgG 滴度（通过酶联免疫吸附试验 [ELISA]）和抑郁症筛查问卷（患者健康问卷 [PHQ-9] [n=280] 和 PHQ-2 [n=26]）。之间的关联刚地弓形虫使用多变量线性方法对年龄和性别进行调整，分析抑郁症筛查问卷中的 IgG 和烦躁/绝望和快感缺失评分。血清强度与当前的烦躁/绝望（p = 0.045）和当前的联合快感缺乏和烦躁/绝望（p = 0.043）相关，而与简单的快感缺乏和过去/终生（而不是当前）表型的关联并不显着。这些结果表明需要进行更大规模的纵向研究来证实烦躁/绝望与刚地弓形虫IgG 滴度。目前的绝望是 SSDV 的一个已知风险因素，它对认知行为疗法的反应特别好，并且可能是针对刚地弓形虫- SSDV 高风险的阳性个体。