Prevalence, Severity, Concomitant Factors, and Natural Trajectory of Insomnia in Patients with Long COVID

<b>Background/Objective:</b> Insomnia is a clinically important symptom in Long COVID; however, few studies have addressed the presentation and course of insomnia symptoms in patients with Long COVID. <b>Methods:</b> The Insomnia Severity Index (ISI) was administered as part of a comprehensive baseline neuropsychological evaluation (Time 1) for patients with Long COVID at an Academic Medical Center (AMC). Data were gathered on 172 consecutively referred patients between the dates of November 2020 and May 2022. The mean age of patients at Time 1 was 49 years (range: 18 to 78), with a mean of 15 years of education. Patients were 70% female and 30% male and identified as White/Caucasian (78%), Black/African American (21%), or American Indian (1%). Patients' severity of COVID-19 infection and self-reported emotional, somatic, cognitive, and fatigue symptoms were also gathered to identify concomitant risk factors for insomnia in Long COVID. Patients were then followed to observe the natural trajectory of insomnia complaints in Long COVID, with the Time 2 evaluation a mean of 9 months after the Time 1 evaluation. <b>Results:</b> Seventy-eight percent of Long COVID patients reported insomnia symptoms at Time 1, with 30% reporting Subthreshold Insomnia symptoms (ISI Score = 8-14), 30% reporting Moderate Insomnia symptoms (ISI Score = 15-21), and 18% reporting Severe Clinical Insomnia (ISI Score = 22-28). Severity of acute COVID-19 infection was not correlated with severity of insomnia in Long COVID; however, being non-white (<i>r</i> = 0.24, <i>n</i> = 172, <i>p</i> < 0.01) and having higher self-reported levels of anxiety (<i>r</i> = 0.41, <i>n</i> = 172, <i>p</i> < 0.01), depression (<i>r</i> = 0.52, <i>n</i> = 172, <i>p</i> < 0.01), perceived stress (<i>r</i> = 0.38, <i>n</i> = 172, <i>p</i> < 0.01), somatic symptoms (<i>r</i> = 0.51, <i>n</i> = 172, <i>p</i> < 0.01), cognitive failures, and fatigue were significantly correlated with insomnia symptoms. Insomnia was also significantly correlated with lower global cognitive function (<i>r</i> = 0.51, <i>n</i> = 172, <i>p</i> < 0.01) and lower cognitive flexibility (<i>r</i> = -0.17, <i>n</i> = 172, <i>p</i> < 0.05). There was a statistically significant decrease in reported ISI scores from Time 1 to Time 2 (<i>t</i> = -3.04; <i>p</i> = 0.003); however, ISI mean scores at both Time 1 (ISI Score = 14) and Time 2 (ISI Score = 12) remained in the Subthreshold Insomnia range (ISI score 8-14). <b>Conclusions:</b> Findings suggest that a large majority of Long COVID patients experience insomnia symptoms. Additionally, insomnia symptoms did not dissipate over time in a clinically meaningful way and were highly correlated with reduced global cognitive function, reduced cognitive flexibility, and higher levels of reported mood symptoms, fatigue, somatic symptoms, and experience of cognitive failures. Thus, there is a pressing need for intervention strategies to treat insomnia in Long COVID patients.