Participants were undergraduate students at a private university, public university, or community college in the United States. To be included, participants had to be at least 18 years old and enrolled as full-time students as part of class years 2020, 2021, 2022, or 2023. Between April and June 2020, participants were recruited through two channels. First, an email was sent to undergraduate students at Boston College. Second, participants were recruited online via Reddit, a social news platform and online forum.

An invitation to participate in the study was posted on over 20 university-related and survey recruitment subreddits (a subreddit is an online community with user-created threads dedicated to a specific topic). One such subreddit utilized for recruitment in this study was r/SampleSize, a community of over 40,000 users assembled for the express purpose of survey recruitment and participation [23]. Subreddits such as these have been shown to be a good source of diverse and viable participants [23] and are useful for inexpensive participant recruitment and reliable data collection [24, 25]. For the purpose of the current study, face-to-face interviews during this time had to be avoided because of the US lockdown and ongoing public health crisis. The study received 1,734 completed responses. After excluding students younger than 18 (n = 34), part-time students (n = 135), and students with incomplete responses (n = 488) from our analyses, our final sample size was 1,077.

DASS (Depression, Anxiety, and Stress Scale): The online survey included the 21-item DASS-21 scale on mood and stress [26]. Based on the scores, participants were classified into “normal” (a score of 0–9 for depression, 0–7 for anxiety, and 0–14 for stress), “mild” (10–13, 8–9, 15–18), “moderate” (14–20, 10–14, 19–25), “severe” (21–27, 15–19, 26–33), and “extremely severe” (28+, 20+, 34+) categories. The purpose of these questions was to assess the severity of depression, anxiety, and stress during the COVID-19 pandemic. Previous studies have verified the validity of the DASS-21 scale as a routinely-used clinical and non-clinical self-report scale [27, 28]. One sample statement that participants were to score for depression was “I was unable to become enthusiastic about anything”; one sample statement for anxiety was “I worry about situations in which I might panic and make a fool of myself”; and one sample statement for stress was “I tended to over-react to situations”. Participants were given the option to choose between “once a week or less” (score = 0), “2–3 times a week” (= 1), “4–6 times a week” (= 2) and “7 times a week or more” (= 3). The corresponding sum of scores was used to assess the severity of depression, anxiety, and stress. Cronbach’s α for the items in this test was 0.934, indicating excellent internal consistency in the questionnaire.

COVID-19 Evaluation: The first portion of the survey consisted of a series of questions meant to measure how COVID-19 may have affected students’ social life and mental health. Students were asked about hours of studying per day (“1–2 h,” “3–5 h,” “5–8 h,” and “8+ h”), hours spent on extracurricular activities per week (participants typed in number of hours), and hours of sleep received per night (“4 h or less,” “5–7 h,” “7–8 h,” and “8+ h”) before the pandemic (e.g., “How many hours of sleep did you get per night (BEFORE the COVID-19 pandemic)?”) and during the pandemic (e.g., “How many hours of sleep do you [currently] get per night?”).

Coping Strategies: Participants were asked to select up to three ways they managed their stress. Seven response categories were given: “talk to friends,” “talk to family members,” “home workout/indoor sports,” “meditate,” “do favorite hobbies,” “walk outside,” and “other”. When participants chose “other”, they were asked to specify. Participants were provided with an open-ended question at the end of the survey to further elaborate on experiences that were not captured by previous questions.

Before taking the survey, all participants provided informed consent. Participants were made aware of all risks and benefits associated with the survey, confidentiality, and right to withdraw their voluntary participation at any time. The survey, which took 10 min to complete, consisted of four components: social demographics, school adjustments, DASS-21 questions, and an optional open-ended question. As an incentive for participation, participants were entered into a raffle for a chance to win a $10 Amazon gift card (15 participants were awarded a gift card). The survey was accessible online for 9 weeks (from April to June 2020). The procedure was approved by the university’s institutional review board in April 2020, ensuring the protection of human subjects in this research in compliance with US federal law.

Statistical analyses were conducted using R-Studio statistical software (version 1.3.959, 2009–2020 R-Studio, PBC). In the first phase of analysis, descriptive statistics were used to describe the demographics of the sample and the distribution of the three mental health outcomes among students. Next, t-tests were used to test whether moving to remote learning had an effect on stress, anxiety, and depression. Paired t-tests were used to determine differences in the hours of sleep, study, and extracurricular activities before and during the pandemic. Bivariate regression analysis was used to determine whether participants’ responses to moving classes to remote learning were associated with stress, anxiety, and depression. Regression analysis tested whether changes in the hours of sleep and study during COVID-19 were associated with stress, anxiety, and depression. Lastly, a multivariate OLS system was used to determine whether gender, having a family member who tested positive for COVID-19, number of times participants left their homes, school performance after moving to remote learning, and changes in the hours of sleep and studying were associated with stress, anxiety, and depression.

Most participants were students at public universities (70.5%), followed by those from private universities (28.5%) or community colleges (0.7%). 0.3% of participants preferred not to answer this question. Participants were categorized as students in the class of 2020 (16.6%), 2021 (26.1%), 2022 (29.1%), and 2023 (24.4%), respectively. 3.8% of participants preferred not to answer this question (Table 1). Female participants accounted for 51.4% of the sample. Slightly more than half of the participants were Caucasian (52.8%), one fourth were Asian/Pacific Islander (24.7%), about one tenth were Hispanic/Latinx (8.9%), and about 4% were African American (3.7%). 0.4% of participants self-identified as Native American. While the majority of participants were US students (94.3%), some participants were international students (4.9%) and a few participants preferred not to answer (0.8%).

Using DASS-21 scores, 19%, 20%, and 28% of participants were categorized as having “severe” or “extremely severe” levels of stress, anxiety, and depression, respectively (% “severe” + % “extremely severe”) (Figure 1) (Table 2). These results indicate an increase of “severe” and “extremely severe” levels of stress, anxiety, and depression in comparison to a sample baseline, non-pandemic DASS-21 scores, with levels of stress, anxiety, and depression at 11%, 15%, and 11%, respectively [29].

COVID-19 disrupted traditional classroom instruction and led to remote learning, as 69.3% of participants claimed that moving to remote learning had a negative impact on their school performance, while 30.7% of participants noted a positive impact of remote learning on school performance. Moreover, in terms of the association between school performance and mental health, a t-test showed that participants who claimed that remote learning had a negative impact on their school performance had significantly higher scores in stress (Figure 2, p < 0.001), anxiety (Figure 2, p < 0.001), and depression (Figure 2, p < 0.001), compared to peers who reported the opposite. A bivariate regression analysis further confirmed that students’ opinions about remote learning were significantly associated with stress (p < 0.001), anxiety (p < 0.001), and depression (p < 0.001). Participants were also asked about changes in hours spent on extracurricular activities, studying, and sleeping before and during COVID-19 comparatively. A paired two-sample t-test showed a significant increase in the hours of sleep (before COVID-19: 6.7 h; during COVID-19: 7.7 h, p < 0.001), a significant decrease in hours spent on extracurricular activities (before COVID-19: 9.4 h; during COVID-19: 6.2 h, p < 0.001), and a significant decrease in hours spent studying (before COVID-19: 4.2 h; during COVID-19: 3.6 h, p < 0.001).

Regression analysis was implemented to find correlates of stress, anxiety, and depression. For survey questions addressed in regard to pre-pandemic conditions, regression analysis showed that hours of sleep was associated with stress (p < 0.001), anxiety (p < 0.001), and depression (p < 0.001), but hours of studying was not associated with stress (p = 0.33), anxiety (p = 0.213), and depression (p = 0.056). However, during COVID-19, regression analysis showed that neither hours of studying nor hours of sleep were associated with stress (p = 0.429 and p = 0.678), anxiety (p = 0.283 and p = 0.506), and depression (p = 0.0517 and p = 0.665).

Turning to multivariate OLS regression models, several factors were found to have significant associations with stress and anxiety. Being a male participant (p < 0.001), having a family member who tested positive (p < 0.001), leaving home three times a week (p < 0.05), believing that school performance was affected negatively by moving to remote learning (Figure 2, p < 0.001), and hours of sleep during COVID-19 (“5–6 h” p < 0.05, “7–8 h” p < 0.001, “8+ h” p < 0.001) were significant correlates of stress (Table 3). As for depression, being a male participant (p < 0.01), leaving home once a week (p < 0.05), believing that school performance was affected negatively by moving to remote learning (p < 0.001), hours spent studying (“3–5 h” p < 0.001, “5–8 h” p < 0.05), and hours of sleep during COVID-19 (“5–6 h” p < 0.01, “7–8 h” p < 0.001, “8+ h” p < 0.001) were significant correlates. For stress management, talking to a family member was significantly associated with stress (p < 0.05), anxiety (p < 0.05), and depression (p < 0.05). Engaging in favorite hobbies was only correlated with depression (p < 0.05).

Female participants showed a larger percentage of severe and extremely severe levels of stress (severe; 16% and extremely severe; 7%), anxiety (8%; 15%), and depression (12%; 18%) in comparison to male participants’ stress (severe; 11% and extremely severe 3%), anxiety (5%; 10%), and depression (11%; 14%) levels (Figure 3). Chi-squared analysis showed being female was associated with severe and extremely severe levels of stress (x-squared = 30.497, df = 4, p < 0.001), anxiety (x-squared = 19.501, df = 4, p < 0.001), and depression (x-squared = 17.59, df = 4, p < 0.01). Two-sample t-test showed that female participants have a higher score in stress (p < 0.001), anxiety (p < 0.001), and depression (p < 0.001) in comparison to male participants. Regression analysis showed that gender is associated with stress (p < 0.001), anxiety (p < 0.001), and depression (p < 0.001).

Recall that the survey asked participants to choose up to three ways they managed their stress during the COVID-19 pandemic. Almost half (47.9%) of participants reported that they talked to family members, 76% of participants engaged in their favorite hobbies, and 32.2% of participants walked outside as one of their three choices. Although the vast majority of the open-ended responses included some sentiment of stress, many individuals did have positive experiences to share. Some participants noted that conversing with significant others, in addition to immediate family, was cathartic (“I’ve been [...]reach [ing] out to my boyfriend, at the very least. These things, along with the positive experience of being around a happy family and the safety of our own home, has positively contributed to my mental wellbeing.”). In a simpler sense, some have made the most of their time while at home, with one participant noting that they were “Just staying inside and trying to learn new things.”

In the open-ended question, one participant from the class of 2021 said the following of their experience during lockdown: “I have been feeling quite depressed. I feel like I have no control over my life ... I cannot plan for the future and my extracurriculars that were going to help me prepare for grad schools have been affected.” Another participant from the class of 2021 said, “Anxious and overwhelmed … I feel like I have less access to academic advising because … professors have not answered my emails. It’s been difficult to focus at home because my parents [are] working over the phone ….”

Many individuals expressed a lack of motivation to perform well on academic tasks noting severe procrastination, loss of direction, and overall dissatisfaction with the progression of the semester. One participant said, “I feel … grateful that I am healthy. However, I also have struggled to find any motivation to do my work or be active. Usually I can get things done because I look forward to having fun or relaxing on weekends, but now it is harder to get things done when it feels like that is all I am doing with nothing fun to look forward to.” Other participants found it challenging to engage with online classes. For example, one participant said, “Online learning is difficult because I feel zero engagement.”

One participant said that they felt suffocated. They said, “I want to leave the house, see new people, go to stores, but I only leave my house about 1–2 times a week.” In addition, leaving home a few times a week may have given students the opportunity to distance themselves from their families and home environment. One participant said, “My parents and I argue, and I feel like my mental health issues are having a negative effect on my family.” Another participant talked about the challenge of staying at home with family, saying, “Being at home with my family has taken a toll on my mental health. [We] do not have a great relationship, and being stuck at home has exacerbated our problems … ” One participant claimed that living temporarily away from family made them “feel great.”

Because the survey was distributed during the lockdown period, an online convenience sampling method had to have been utilized. This sampling method limited the representativeness and generalizability of the findings reported, as we were necessarily constrained to only those responses from students with access to the Internet. Thus, it is not possible to draw causal inferences due to the nature of this study. The survey also had some duplicate questions and questions that did not provide the capability to select multiple options. For example, one question asked participants about COVID-19 safety precautions taken, where the selection of multiple options could have been appropriate. The term “extracurricular” was also left to the interpretation of participants. A better survey question could have offered participants the option to define extracurricular activities. Furthermore, in addition to DASS-21, the study could have benefited from the utilization of a resilience scale to examine how certain resilience factors could have protected individuals’ mental health from COVID-19 related stress. Allowing participants to evaluate resilience may have permitted greater insight into students’ mental health and wellbeing.

COVID-19 remains a credible threat to undergraduate students, beyond the acute and lingering physical effects of the virus. Students spent less time studying, complemented by the finding that the transition to remote learning hindered the majority of students’ academic experience. Students who left home more frequently may have had a greater opportunity to socialize, which lessened the stress and mental burden of lockdown. The majority of participants also stated that talking to family and engaging in favorite hobbies were beneficial for stress management. As such, these results showed that the pandemic led to significant changes in students’ academic performance, social life, and mental health.