**1. Introduction**

December 2019 saw the emergence of a novel severe acute respiratory syndrome, coronavirus pneumonia (COVID-19) outbreak, which subsequently became a global pandemic [1]. COVID-19 elicits challenging psychological and psychiatric responses due to its sudden and unpredictable nature, creating a sense of uncertainty and vulnerability, while challenging individuals' sense of personal and societal safety [2]. This may be amplified by the treatment-resistant nature of COVID-19 to common medications and the delay in contraction to symptom onset [3]. Patients, health professionals, and the general public face increasing psychological demands and pressure which may in itself lead to challenges with anxiety, fear, depression, and sleep difficulties, all of which need to be considered and targeted in the overall deployment of the disease control measures [4].

COVID-19 is associated with a significant mental health burden both in the acute phase and the long-term from people who are exposed to the virus and those not directly exposed. Anxiety, depression, cognitive impairment, delirium, psychosis, irritability, insomnia, and post-traumatic stress disorder are prevalent following COVID-19 infection [5–8]. One-third of the first 153 COVID-19 cases in the UK were diagnosed with new-onset mental health problems including psychosis (43%), cognitive decline (26%), and affective disorder (17%) [9]. Further to the psychological response to COVID-19, in a recent COVID-19 study using a national cross-sectional survey based design in Italy [10], it was found that previous history of trauma and medical problems, or having an acquaintance infected was associated with higher levels of depression and anxiety.

With a view to reduce infection and control the outbreak of a virus, many countries undertake stepped measures such as social distancing, the reduction and cancellation of large public gatherings, self-isolation recommendations, quarantine in a dedicated facility, and mass public quarantine (Public Health England, 2020). While quarantine can be necessary during major infectious disease outbreaks from a population-health perspective, a recent systematic review suggests that quarantine itself is often associated with negative psychological and physical effects [1,11]. For some, the psychological impact of being in a pandemic is wide-ranging [11], significant, and long-lasting [12,13], requiring effective and accessible psychological support be put in place as early as possible.

In recent years, much of the research into the psychological sequalae following public quarantine has resulted from similar epidemics (e.g., Severe Acute Respiratory Syndrome (SARS) circa. 2003; Equine influenza circa. 2008; and Swine Flu circa. 2009 [H1N1 Influenza]). Research suggests that quarantine may result in a higher prevalence of symptoms of psychological distress [14], emotional disturbance [15], depression [16], stress [17], low mood with irritability and insomnia [18], post-traumatic stress symptoms [19], anger [20], and emotional exhaustion [21]. Low mood (73% of 903) and irritability (57% of 903) are among the most prevalent symptoms of psychological distress reported [18]. People quarantined because of being in close contact with those who potentially had SARS [19] reported various negative responses during the quarantine period: over 20% (230 of 1057) reported fear, 18% (187) reported nervousness, 18% (186) reported sadness, and 10% (101) reported guilt. However, not all studies have found evidence of psychological distress following quarantine. For example, [22] compared undergraduates who had been quarantined with those not quarantined immediately after the quarantine period and found no significant difference between the groups in terms of post-traumatic stress symptoms or general mental health problems. Recently, the typical responses to COVID-19 have been reported as panic, fear to go out, excessive disinfection, disappointment, fear, irritability, aggressive behavior, and extreme optimism or pessimism [23].

Mental health risks associated with COVID-19 have yet to be systematically studied; however, the emerging literature on COVID-19 as well as previous studies on infectious disease outbreaks provide insights into probable risk factors and correlates of mental health challenges and chronic psychological distress [24]. There is also emerging evidence that specific members of society, e.g., parents, may be experiencing additional psychological distress due to increased and unstable financial demands, school closures, and suspended recreational outlets, which would have support personal and familial coping [25,26]. A better classification and quantification of mental health and psychological needs following COVID-19 will allow for the appropriate consideration of therapeutic frameworks, service-based funding considerations, intervention integration through non-routine modalities, and to consider service models and accessibility for those vulnerable and in need [27].

The primary aim of the study was to investigate the mental health and well-being of adults in Ireland during the quarantine period of the COVID-19 crisis and examine the reliability and validity of a new instrument for assessing stresses and things for which people felt grateful that were specifically related to the COVID-19 crisis (the Effects of COVID-19 Questionnaire [ECQ, Berry and Carr, 2020]). For the purpose of this study, the quarantine period is defined as the period of time in which the initial national lockdown occurred in Ireland. The following specific questions were addressed:

• Were mean levels and rates of depression, anxiety, and stress significantly higher during the quarantine period?

