Chemical Senses and Mental Health Lab, Department of Psychology, School of Public Health, Southern Medical University, Guangzhou, China.
Department of Psychiatry, Zhujiang Hospital, Southern Medical University, Guangzhou, China.
Aust N Z J Psychiatry. 2022 Jan;56(1):71-80. doi: 10.1177/0004867421998774. Epub 2021 Mar 16.
Olfactory deficits have been reported in bipolar disorder, but this finding is controversial. This study investigated whether olfactory deficit can serve as a specific marker for bipolar disorder by comparing olfactory function in different mood episodes of bipolar disorder. We also compared olfactory function in bipolar disorder and other mental disorders - namely, major depressive disorder and schizophrenia.
The study consisted of two experiments. Experiment 1 enrolled 175 bipolar disorder patients (70 depressed subgroup, 70 manic subgroup and 35 euthymic subgroup) and 47 controls. Experiment 2 enrolled the participants from Experiment 1, along with 85 major depressive disorder and 90 schizophrenia patients. The Sniffin' Sticks test was used to evaluate odour identification ability and odour threshold (as a measure of odour sensitivity). The Hamilton Depression Rating Scale and Young Mania Rating Scale were used to assess depressive symptoms in all subjects and manic symptoms in bipolar disorder patients, respectively. We also used the Positive and Negative Syndrome Scale to assess clinical symptoms in schizophrenia patients.
All three bipolar disorder patient subgroups (depressed, manic and euthymic subgroup) showed reduced odour identification ability compared to controls; however, only patients in the acute phase of a mood episode (depressed, and manic subgroup) showed impaired odour sensitivity. Clinical symptoms were negatively correlated with odour sensitivity but not odour identification ability. Bipolar disorder and major depressive disorder patients showed less odour identification and sensitivity impairment than schizophrenia patients.
Odour sensitivity is a potential dopaminergic marker for distinguishing between bipolar disorder patients in acute phase vs remission, while odour identification is a trait but a nonspecific marker of bipolar disorder.
双相障碍患者存在嗅觉缺陷，但这一发现存在争议。本研究通过比较双相障碍不同心境发作时的嗅觉功能，探讨嗅觉缺陷是否可作为双相障碍的特异性标志物。我们还比较了双相障碍与其他精神障碍（即重度抑郁症和精神分裂症）的嗅觉功能。
该研究包括两个实验。实验 1 纳入了 175 例双相障碍患者（70 例抑郁亚组、70 例躁狂亚组和 35 例缓解亚组）和 47 名对照。实验 2 纳入了实验 1 的参与者，以及 85 例重度抑郁症患者和 90 例精神分裂症患者。采用嗅觉识别能力测试（Sniffin' Sticks 测试）评估气味识别能力和气味阈值（作为嗅觉敏感性的衡量标准）。所有受试者均采用汉密尔顿抑郁评定量表评估抑郁症状，双相障碍患者采用 Young 躁狂评定量表评估躁狂症状。我们还采用阳性和阴性症状量表评估精神分裂症患者的临床症状。
与对照组相比，所有三组双相障碍患者（抑郁亚组、躁狂亚组和缓解亚组）的嗅觉识别能力均降低；然而，仅处于心境发作急性期的患者（抑郁亚组和躁狂亚组）的嗅觉敏感性受损。临床症状与嗅觉敏感性呈负相关，与嗅觉识别能力无关。与精神分裂症患者相比，双相障碍和重度抑郁症患者的嗅觉识别和敏感性损伤程度较轻。
嗅觉敏感性可能是区分双相障碍患者急性期与缓解期的潜在多巴胺标志物，而嗅觉识别是双相障碍的一种特质而非特异性标志物。
