Table 1.
Summary of findings in studies on changes in sleep quality under COVID-19 lockdown compared with the previous period.
| Study | Country | Sample | Method |
Key results on changes in sleep quality (T0 vs T1) | |||
|---|---|---|---|---|---|---|---|
| Data collection | Baseline assessment (T0) | Lockdown assessment (T1) | Sleep quality measures | ||||
| Chandra et al., 2020 [7] | Nepal | Young adults (Mage = 29.5 ±9.77 years) | Web-based survey | Retrospectively self-reported (time period not specified) | Completed between 20th April and 2nd May 2020 (after pandemic) | ISI | Increase in ISI total score (more insomnia symptoms) at T1 than at T0. Longer SOL, worse sleep maintenance, lower satisfaction with current sleep pattern, and stronger worries about current sleep problem at T1 than at T0. No significant differences/changes on awakening problems, impairment of quality of life, interference with daily functioning between T1 and T0. |
| Barrea et al. [8] | Italy | Adults (age range = 18–65 years; Mage = 44.90 ± 13.30 years) | Telephone interview | Retrospectively self-reported (time period not specified) | After 40 days of lockdown (started on 12th March 2020) | PSQI | Increase in PSQI total score (more sleeping difficulties) at T1 than at T0. Worse sleep quality, longer SOL, lower sleep efficiency, greater sleep disturbance, and daytime dysfunction at T1 than at T0. No significant differences/changes in sleep duration and hypnotic drugs between T1 and T0. |
| Beck et al. [9] | France | 26% < 35 years old 64% > 35 years old | Web-based survey | Data from the French Health Barometer Survey (2017) | A subsample of the panel interviewed in 2017 completed the survey between 3rd March and 2nd April 2020 | Ad-hoc questions on sleep quality | Greater trouble sleeping during the past 8 days at T1 than at T0. Greater use of sleeping pills at T1 than at T0. |
| Blume et al. [10] | Austria, Switzer-land, Germany | Young adults (median age range = 26–35 years) | Web-based survey | Retrospective self-reported sleep quality in relation to the time before the lockdown (Austria on 13 March; Switzerland on 16 March, Germany on 23 March) | Completed between March and April 2020 | Ad-hoc questions on sleep quality | Lower sleep quality (slightly decreased), but longer sleep duration (∼13 min more under lockdown than before lockdown) at T1 than at T0. |
| Casagrande et al. [11] | Italy | Young adults (age range: 18–89 years; Mage = 30.00 ± 11.50 years) | Web-based online survey | Data from general population (derived from previous published studies) | Completed between 18th March and 2nd April 2020 | PSQI | No significant differences/changes between respondents under restrictions (T1) than general population (T0) on PSQI total score and its subscales, except for PSQI Sleep latency and PSQI Daytime dysfunctions. |
| Cellini et al. [5] | Italy | Young adults (age range = 18–35 years; Mage = 23.91 ± 3.60 years) | Web-based survey | Retrospective self-reported sleep quality in relation to the time before the lockdown (period from 3rd to 10th February) | Completed between 24th and 28th March 2020, in relation to the second week of lockdown (17th-23rd March 2020) | PSQI | Increase in PSQI total score at T1 compared with T0. Prolonged Bedtime (∼41 min later under lockdown) and Waketime, and longer TIB at T1 than at T0. |
| Gao and Scullin [12] | USA | Adults (Mage = 38.04 ± 11.65 years) | Web-based survey | 86 participants completed a survey on 17 February 2020 All participants were asked to retrospectively estimate their sleep habits before lockdown (time period not specified) |
Completed between 25–27 March 2020, after two weeks of US lockdown and social distancing |
PSQI; FIRST; SSS |
Baseline vs Quarantine: No significant differences/changes in PSQI total score, FIRST total score, and SSS total score between T1 and T0. Increase in sleep duration, delayed bedtime and waketime, and fewer sleep disturbances at T1 than at T0. Retrospective recall of sleep prior to the quarantine phase: Greater sleep onset latency, fewer awakenings in the middle of the night, earlier bedtime, later waketime, and feeling more rested prior to the COVID-19 quarantine (T0) than at T1. No significant differences/changes in sleep duration between T1 and T0. |
| Hisler and Twenge [13] | USA | Adults (age range = 18–60+ y old; Mage = 43.35±14.88 years) | Web-based survey | NHIS 2018 (nationally representative sample of internet users) | Completed on 27th April 2020 (sample with similar demographic characteristics to the NHIS 2018 sample) | Ad-hoc questions on sleep quality and habits | Slightly shorter sleep duration at T1 than in 2018. Greater prevalence of insufficient sleep duration, difficulty staying asleep, and higher number of days with difficulty falling asleep and not feeling rested at T1 than at T0. |
| Gupta et al. [14] | India | Adults (Mage = 37.32 ±13.39 years) | Web-based survey | Retrospectively self-reported for sleep patterns (time period not specified) | Completed between 28th April and 10th May 2020 | Ad-hoc questions on sleep quality and habits; ISI | Prolonged bedtime and waketime, longer SOL, increased daytime napping and not refreshed days at T1 than at T0. Just over 10% of the sample met the criteria for clinically significant insomnia according to ISI, however (% similar to that of the general population before lockdown). |
| Leone et al. [6] | Argentina | Adults (age range = 20–70 years) | Web-based survey | Participants who had completed the Crono Argentina survey (www.cronoargentina.org) either on February to May 2018 or 2019, or in February 2020. | April 2020 | PSQI | No significant differences/changes in PSQI total score between T1 and T0. The effects of lockdown on sleep quality and patterns were greater for younger people and those whose working status changed. Those who did not work away from home during lockdown slept better, but their chronotype became more delayed. |
| Marelli et al. [15] | Italy | Young adults (age range: 19–67 years; Mage = 22.84 ± 2.68 years) | Web-based survey | Retrospectively self-reported (time period not specified) | Completed between 24th March and 3rd May 2020 | PSQI; ISI | Increase in PSQI total score and ISI total score at T1 compared with T0. Prolonged bedtime and waketime, and longer sleep latency at T1 compared with T0. No differences/changes in TST and TIB between before and during COVID-19 emergency. |
| Salehinejad et al. [16] | Germany | Young adults (Mage = 25.79±7.31 years) | Web-based survey | Retrospectively self-reported (time period not specified) | Completed between 20th and 28th April 2020 | PSQI | Higher PSQI total score at T1 than at T0. Lower self-reported sleep quality, and higher daily disturbances at T1 than at T0. No differences/changes in sleep efficiency between T1 and T0. Prolonged bedtime and waketime, and longer sleep duration at T1 than at T0. |