The COVID-19 pandemic has had significant impacts on mental health, both directly through the virus's effects on the brain and indirectly through the pandemic's overall psychological effects. A systematic review of 43 studies found that COVID-19 patients had high levels of post-traumatic stress symptoms (PTSS) and depressive symptoms. Pre-existing psychiatric disorders worsened during the pandemic. Healthcare workers experienced increased depression, anxiety, psychological distress, and poor sleep quality. The general public also showed lower psychological well-being and higher anxiety and depression scores compared to before the pandemic. Factors associated with higher risk of psychiatric symptoms include female gender, poor self-rated health, and living in urban areas. The review highlights the need for further research to improve treatment and mental health care planning, as well as preventive measures for potential future pandemics.The COVID-19 pandemic has had significant impacts on mental health, both directly through the virus's effects on the brain and indirectly through the pandemic's overall psychological effects. A systematic review of 43 studies found that COVID-19 patients had high levels of post-traumatic stress symptoms (PTSS) and depressive symptoms. Pre-existing psychiatric disorders worsened during the pandemic. Healthcare workers experienced increased depression, anxiety, psychological distress, and poor sleep quality. The general public also showed lower psychological well-being and higher anxiety and depression scores compared to before the pandemic. Factors associated with higher risk of psychiatric symptoms include female gender, poor self-rated health, and living in urban areas. The review highlights the need for further research to improve treatment and mental health care planning, as well as preventive measures for potential future pandemics.