title: Patients with chronic insomnia have selective impairments in memory that are modulated by cortisol.
abstract: Memory impairment is a frequent complaint in insomniacs; however, it is not consistently demonstrated. It is unknown whether memory impairment in insomniacs involves neuroendocrine dysfunction. The participants in this study were selected from the clinical setting and included 21 patients with chronic insomnia disorder (CID), 25 patients with insomnia and comorbid depressive disorder (CDD), and 20 control participants without insomnia. We evaluated spatial working and reference memory, object working and reference memory, and object recognition memory using the Nine Box Maze Test. We also evaluated serum neuroendocrine hormone levels. Compared to the controls, the CID patients made significantly more errors in spatial working and object recognition memory (p < .05), whereas the CDD patients performed poorly in all the assessed memory types (p < .05). In addition, the CID patients had higher levels (mean difference [95% CI]) of corticotrophin-releasing hormone, cortisol (31.98 [23.97, 39.98] μg/l), total triiodothyronine (667.58 [505.71, 829.45] μg/l), and total thyroxine (41.49 [33.23, 49.74] μg/l) (p < .05), and lower levels of thyrotropin-releasing hormone (-35.93 [-38.83, -33.02] ng/l), gonadotropin-releasing hormone (-4.50 [-5.02, -3.98] ng/l) (p < .05), and adrenocorticotropic hormone compared to the CDD patients. After controlling for confounding variables, the partial correlation analysis revealed that the levels of cortisol positively correlated with the errors in object working memory (r = .534, p = .033) and negatively correlated with the errors in object recognition memory (r = -.659, p = .006) in the CID patients. The results suggest that the CID patients had selective memory impairment, which may be mediated by increased cortisol levels.
authors.affiliation: Department of Neurology, Affiliated Chaohu Hospital of Anhui Medical University, and the Center of Psychologic Medicine of Anhui Province, Chaohu, China. doctorcgh@163.com.|Department of Neurology, First Affiliated Hospital of Anhui Medical University, Hefei, China. doctorcgh@163.com.
authors.forename: Gui-Hai
authors.initials: GH
authors.lastname: Chen
authors.affiliation: Department of Neurology, First Affiliated Hospital of Anhui Medical University, Hefei, China.|Department of Neurology, Second Affiliated Hospital of Anhui Medical University, Hefei, China.
authors.forename: Lan
authors.initials: L
authors.lastname: Xia
authors.affiliation: Department of Neurology, First Affiliated Hospital of Anhui Medical University, Hefei, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Neurology, First Affiliated Hospital of Anhui Medical University, Hefei, China.
authors.forename: Xue-Wei
authors.initials: XW
authors.lastname: Li
authors.affiliation: Department of Neurology, Affiliated Chaohu Hospital of Anhui Medical University, and the Center of Psychologic Medicine of Anhui Province, Chaohu, China.
authors.forename: Chuan-An
authors.initials: CA
authors.lastname: Jiao
mesh_terms: D000328:Adult; D003866:Depressive Disorder / Q000097:blood / Q000150:complications / Q000523:psychology; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D008297:Male; D008568:Memory; D008570:Memory, Short-Term; D008875:Middle Aged; D021641:Recognition, Psychology; D007319:Sleep Initiation and Maintenance Disorders / Q000097:blood* / Q000150:complications / Q000523:psychology*; D065852:Spatial Memory; D055815:Young Adult
chemical_list: D006854:Hydrocortisone
keywords: Hormones; Insomnia disorder; Memory; Nine Box Maze Test