0660 Association between sleep architecture and attention and memory abnormalities in patients with insomnia disorder comorbid with major depression
Authors: Olivera-López Carlos , Ortega-Robles David , Salvador-Cruz Judith , Jimenez-Genchi Alejandro 
Published: May 2022

Abstract

Introduction
Insomnia and major depressive disorder (MDD) are highly comorbid conditions that show a complex bidirectional relationship. The co-occurrence of chronic insomnia disorder (CID) with MDD has been associated with poorer outcomes. Both CID and MDD are independently associated with attention and memory impairments. However, little is known about the relationship between neuropsychological performance and sleep architecture in CID comorbid with MDD. On the basis of this knowledge, we aimed to assess the relationship between PSG parameters and memory and attention performance in patients with CID comorbid with MDD.

Methods
Patients were recruited from the National Institute of Psychiatry at Mexico City. To be included, subjects were required to be females or males, 18 to 60 year-old, with diagnosis of major depressive disorder (MDD) and Insomnia Disorder (DSM 5), without drug/psychological treatment and without comorbidity with other psychiatric or sleep disorders. After giving their signed informed consent, all participants underwent a structured diagnostic interview to confirm diagnoses, two consecutive nights of polysomnographic recording (PSG) and a battery of neuropsychological tests to evaluate different aspects of attention and memory. In addition, the Pittsburgh Sleep Quality Index, the Insomnia Severity Index and the Quick Inventory of depressive symptomatology were applied to assess the severity of insomnia and depression.Statistical Analysis: Descriptive statistics were used for socio-demographic and clinical characteristics; Pearson′s Coefficient Correlation were used for evaluating associations between PSG variables, performance in neuropsychological tests and disorders severity.

Results
Nine men and 10 women with an age range of 21 to 59 years (M= 37.2 SD = 12.9) were included. We found significant associations between total sleep time (TST) and declarative memory (r =.510, p &lt;.05); visuospatial memory and REM sleep latency (r = -582, p &lt;.01); procedural memory and WASO and arousals index (r = -.561 and r = -.530, p &lt;.05); sustained attention and NREM stage N1 (r = -.490, p &lt;.05); errors of commission were negatively related with sleep efficiency (r = -486, p &lt;.05), and positive related to WASO (r = .483, p &lt;.05) and total wake time (r = .486, p &lt;.05). In contrast, no associations were found between the severity of insomnia and depression severity with any cognitive function.

Conclusion
These preliminary findings suggest that changes in sleep continuity in CID comorbid with MDD architecture are significatively associated with attention and memory impairments. In contrast, severity of insomnia and depression seems to have a negligible role in these neuropsychological deficits

Support (If Any)
This study is supported by the National Council of Science and Technology (CONACyT), doctoral studies code 751918, scholarship recipient 697300