This isn't the gotcha you think it is. Lack of serotonin is correlated with depression. Mood and cognition are functions of the brain and the brain can malfunct

This isn't the gotcha you think it is. Lack of serotonin is correlated with depression. Mood and cognition are functions of the brain and the brain can malfunction due to pathogen. Saying this is depression isn't the same as saying it isn't a disease or that it isn't caused by covid-19.