Introduction: The disease caused by the SARS-CoV-2 infection since its outbreak in China in the end of 2019, turned into a pandemic after having reached over 7,834 confirmed cases and 170 deaths worldwide by the end of January 2020. Purpose: The purpose of the current article is to present how SARS (Severe Acute Respiratory Syndrome), MERS (Middle East syndrome) and COVID-19 pandemics affected the mental health of different population subgroups and also to present the determinants of mental illness, in an attempt to understand their negative psychological effects. Material- Methodology: The methodology that was followed in this paper was the review of the international bibliography on the Pubmed, Scopus και Google Scholar on the subject of mental health during pandemics and the presentation of the wide range of psychosocial needs that emerged during the SARS, MERS and COVID-19 pandemics. Results: The conclusions derived from the first literature research on the mental health of different target groups during the COVID-19 pandemic are comparable to those that emerged during the previous two major pandemics. Therefore, the pandemic has demonstrated the necessity of timely mental health care by the immediate adoption of appropriate measures and the implementation of interventions that will be based on the different needs of the population. Conclusions: Although the Greek government took timely measures against the spread of the virus, published research efforts regarding the mental health outcomes within the Greek population, are still in their infancy. At this critical time, mental health assessment and evaluation should be a priority for health authorities in their way to managing psychological crises due to a pandemic.