One of the consequence of having had Covid-19 is the predisposition of becoming depressed. 

The World Health Organisation noted this year that anxiety and depression increased by 25 percent across the globe in just the first year of the Covid-19 pandemic.  In a 2021 study, more than half of American adults reported symptoms of major depressive disorder after a coronavirus infection. The risk of developing these symptoms — as well as other mental health disorders — remains high up to a year after you’ve recovered. One major explanation for the increase is the unprecedented stress caused by the social isolation resulting from the pandemic. Linked to this were constraints on people’s ability to work, seek support from loved ones and engage in their communities.

It’s possible that Covid-19 may even compromise the diversity of bacteria and microbes in the gut. Since microbes in the gut have been shown to produce neurotransmitters like serotonin and dopamine, which regulate mood, this change could be at the root of some neuropsychiatric issues. Gut bacteria manufacture about 95 percent of the body's supply of serotonin, which affects the mood and the feeling of Zing. 

Serotonin and other neurotransmitters travel from the gut to the brain via the vagus nerve. The body's longest nerve that emerges directly from the brain. Magnesium works as an important co-factor required for conversion of tryptophan (from proteins we get from food) to serotonin and melatonin. (Note to self: Must increase my intake of magnesium at night.)