COVID-19 virus emerged in Wuhan, China, in December 2019 and spread rapidly all over the world. Its rapid spread was declared as a “pandemic” by the World Health Organization in March 2020. COVID-19 causes many physical, psychological, and social problems. This study aims to reveal the psychological and behavioral effects of the COVID-19 pandemic on different groups with a literature review. It has been observed that the COVID-19 pandemic caused an increase in fear, anxiety, and anger, anxiety disorders in the general population; however, increased stress and life changes caused an increase in posttraumatic stress disorder, depression, insomnia, and even suicidal thoughts. In the studies carried out in this period, it was understood that some special groups such as individuals with previous psychiatric diseases, children and adolescents, the elderly and those with chronic diseases, and healthcare workers who struggled with the disease were more affected. It is necessary to ensure that sensitive groups, especially healthcare workers, who are at risk in terms of the adverse mental effects of the epidemic, are effectively screened, and appropriate evaluation methods and forms should be developed for this purpose.