The prognosis of COVID-19 (coronavirus disease 2019) is usually poor when it occurs in aged adults or in patients with chronic diseases, which brought a great challenge to clinical practice. Furthermore, widespread depression, anxiety, and panic related to SARS-CoV-2 (severe acute respiratory syndrome-coronavirus 2) infection affected treatment compliance and recovery. Here we report the successful treatment of a 57-year-old male with severe COVID-19, schizophrenia, hypertension, and type 2 diabetes. The patient's negative emotions (such as tension, panic, and anxiety), particularly his aggression and paranoia, seriously hindered treatment, leading to a deteriorating condition. Psychological counseling and supportive psychotherapy were given but the effect was weak. To improve adherence, risperidone and quetiapine fumarate were replaced by olanzapine for anti-schizophrenic treatment to reduce insomnia and anxiety side effects, associated with sedative-hypnotic drugs as well as psychological counseling. The treatment compliance of the patient improved significantly. The patient's serum alanine aminotransferase increased abnormally in the late stage of hospitalization, suggesting potential liver damage after complex medication strategies. We also monitored the changes of lymphocyte subsets and retrospectively analyzed the virus-specific antibody response. The results suggested that dynamic monitoring of lymphocyte subsets and virus-specific antibody response could facilitate disease progression evaluation and timely treatment plan adjustments. An effective psychotropic drug intervention associated with psychological counselling and psychotherapy are essential for the successful adherence, treatment, and rehabilitation of psychiatric disorders in COVID-19 patients.