Loneliness during the Covid-19 Pandemic in Germany: Impact of social factors and polygenic risk scores on interpersonal differences in loneliness and mental health.

The outbreak of Covid-19 negatively affected mental health and elevated loneliness. The subjective feeling of loneliness is influenced by genetic and social factors and has a negative impact on mental health. From March 2020 to June 2021 loneliness was investigated in N  = 517 individuals using monthly acquired questionnaire data and Latent Growth Curve Analysis. Three classes ("average " , 40%; "not lonely", 38%; "elevated loneliness", 22%) were identified, that differ significantly regarding loneliness, mental dysfunction, and response to the lockdown phases. Associations of social factors and polygenic risk scores (PRSs, n  = 361) with class membership were investigated. Individuals with a high PRS for neuroticism are more likely to belong to the "elevated loneliness" class, living with another person is a protective factor. As the " loneliness" class was at highest risk of mental dysfunction, our findings underscore the importance of identifying those individuals to implement counteractive measures.