Department of Neuropsychiatry, Oita University Faculty of Medicine, Idaigaoka 1-1, Hasama-machi, Yufu city, Oita, 879-5593, Japan.
Advanced Trauma, Emergency and Critical Care Center, Oita University Faculty of Medicine, Idaigaoka 1-1, Hasama-machi, Yufu city, Oita, 879-5593, Japan.
Psychopharmacology (Berl). 2017 Nov;234(22):3335-3342. doi: 10.1007/s00213-017-4729-z. Epub 2017 Aug 28.
Several epidemiological studies have shown the inverse association of lithium levels in drinking water and suicide rates; however, it is necessary to perform a clinical study dealing with individual patients.
We analyzed 199 patients including 31 patients with suicide attempts, 21 patients with self-harm, and 147 control patients. All were transferred to a university emergency department suffering from intoxication or injury, were aged 20 or more years, and were alive at the start of the study. The exclusion criteria consisted of suffering from schizophrenia and a past or present history of lithium therapy. These exclusions were applied because it is difficult to determine whether their suicide attempt was induced by the intent to end their life or by psychotic symptoms such as auditory hallucinations, and if the patient had received lithium therapy, the association between the small amount of lithium taken from drinking water and food and serum lithium levels cannot be detected.
There was a significant difference (p = 0.043) between the three groups whereby patients with suicide attempts had significantly lower lithium levels than control patients (p = 0.012) in males but not females. Multivariate logistic regression analysis with adjustment for age and gender revealed that patients with suicide attempts had significantly lower lithium levels than control patients (p = 0.032, odds ratio 0.228, 95% CI 0.059-0.883).
The limitations of the present study are the nature of observational research which cannot reveal a causal relationship and the relatively small number of subjects.
The present findings suggest that higher serum lithium levels may be protective against suicide attempts in lithium therapy-naive individuals.
几项流行病学研究表明，饮用水中的锂水平与自杀率呈负相关；然而，有必要进行一项涉及个体患者的临床研究。
我们分析了 199 名患者，包括 31 名自杀未遂者、21 名自残者和 147 名对照患者。所有患者均因中毒或受伤被转至一所大学急诊部，年龄在 20 岁及以上，且在研究开始时存活。排除标准包括患有精神分裂症和既往或目前的锂治疗史。之所以排除这些因素，是因为很难确定他们的自杀企图是出于结束生命的意图还是由于幻听等精神病症状，而且如果患者接受了锂治疗，那么从饮用水和食物中摄取的少量锂与血清锂水平之间的关联就无法检测到。
三组之间存在显著差异（p=0.043），自杀未遂者的男性血清锂水平明显低于对照组（p=0.012），但女性则无差异。调整年龄和性别后进行多变量逻辑回归分析显示，自杀未遂者的血清锂水平明显低于对照组（p=0.032，优势比 0.228，95%可信区间 0.059-0.883）。
本研究的局限性在于观察性研究的性质，无法揭示因果关系，且研究对象数量相对较少。
本研究结果提示，锂治疗初治个体中较高的血清锂水平可能对自杀企图有保护作用。
