The COVID-19 pandemic is currently a worldwide threat and concern, not only because of COVID-19 itself but its sequelae. The aim of this study was to evaluate whether a relation between COVID-19, Long COVID, and the prevalence of mental health disorders exist. A total of 203 people from Tabasco were included in this study, answering a survey integrated by three dominions: General and epidemiological data, the DASS-21 test (to determine the presence of signs or symptoms suggestive of depression, anxiety, and/or stress) and an exploratory questionnaire about Long COVID syndrome. A descriptive and inferential statistical analysis was made via Microsoft Excel and Graphpad Prism software, evaluating differences through the Mann–Whitney U test and considering p < 0.05 as statistically significant. Of the 203 people surveyed, 96 (47.29%) had had COVID-19 and 107 (52.71%) had not; from the ones that had COVID-19, 29 (30.21%) presented mental health disorders and 88 (91.66%) presented at least one symptom or sign of Long COVID syndrome; meanwhile, 31 (32.29%) presented 10 or more symptoms or signs. From the comparison between the population with previous mental health disorders and COVID-19 and those without background disorders or COVID-19, the results were the following: 27.58% vs. 16.82% presented severe depression, 48.27% vs. 17.75% presented severe anxiety, and 27.58% vs. 20.56% presented severe stress. A high prevalence of mental health effects was observed in patients without COVID-19 and increased in the population with Long COVID syndrome and previous mental health disorders.