Based on a study published at the US National Library of Medicine and National Institutes of Health: Serum 25-hydroxyvitamin D levels and Psychological Distress Symptoms in patients with affective disorders during the COVID-19 Pandemic.

"The ongoing COVID-19 pandemic and related containment measures imposed by governments, including self-isolation and social distancing, have largely affected mental health worldwide. Preliminary data from different countries highlighted increased levels of psychological distress among the general population (Vindegaard and Eriksen Benros, 2020; Xiong et al., 2020). Subjects with mental disorders showed to be even more consistently influenced by the COVID-19 epidemic and lockdown measures, reporting significant worsening of the clinical conditions and potentially higher risk for recurrence (Sani et al., 2020; Vindegaard and Eriksen Benros, 2020; Yao et al., 2020)..."