Loneliness during the last phase of the COVID-19 pandemic in Spain: A longitudinal study of group-based trajectories, risk factors, and consequences in mental health.

INTRODUCTION:The present study aims to investigate the courses of loneliness following a national state of emergency including a curfew due to a rise in COVID-19 cases, associated risk factors, and the effect of loneliness on symptoms of depression and anxiety. METHODS:Data of 2,000 adults in Spain which were interviewed by telephone at the first follow-up of the MINDCOVID project (February-March 2021) and of whom 953 were interviewed nine months later (November-December 2021) were analyzed. Group-based trajectories and mixed models were constructed. RESULTS:Three courses of loneliness were detected: (1) invariant low loneliness (42.6%), (2) decreasing medium loneliness (51.5%), and (3) fairly invariant high loneliness (5.9%). Loneliness courses were associated with the severity and variability of symptoms of depression and anxiety. In contrast to the majority of pre-pandemic studies, younger adults more frequently reported loneliness compared to middle-aged and, particularly, older individuals. Other risk factors for loneliness were being female, being unmarried, and, notably, having pre-pandemic mental disorders. CONCLUSIONS:Future studies should validate whether the newly observed loneliness patterns across age groups persist and assess the evolution of loneliness courses and their impact on mental health, with particular attention given to young adults and individuals with pre-existing mental disorders.