The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) primarily affects the respiratory tract, but sometimes also other organs, including the central nervous system (CNS). It is not well understood how the virus affects the CNS and how frequently it happens. Our review provides insight into the occurrence of mental disorders in Corona Virus Disease 2019 (COVID-19) patients. We also collected information about the biological basis of the susceptibility of brain cells to SARS-CoV-2 and its implication to psychiatric manifestations. We included 24 publications in our review, reporting psychiatric manifestations published between 31 December 2019 and 30 July 2020, using the Preferred Reporting Items for Systemic Review and Meta-Analysis statement. Mental disorders occurred in up to one-fifth of patients during the acute phase of the infection. The most common disorders included anxiety-related disorders, mood-spectrum disorders, impaired consciousness, confusion, delirium and psychosis. The onset of psychiatric manifestations is not always preceded by respiratory symptoms, but occurs initially in COVID-19 patients. Long-term manifestations are mainly depression and post-traumatic stress symptoms. The obtained data allow the statement that direct infection of the CNS by SARS-CoV-2 could be responsible for the observed findings. To further investigate long-term psychiatric manifestations, randomised controlled studies must be initiated.