13 October

If you know somebody whose personality changed significantly after Covid infection, particularly towards dark thoughts and depression, the most likely cause is dopamine senescence. There are neurons in the brain that produce dopamine, a key neurochemical responsible for mood as well as movement. Covid attacks these and causes them to stop working. Dopamine is also heavily impacted in Parkinson’s Disease, it was this chemical Oliver Sacks and others targeted to bring Parkinson’s patients out of their frozen states, at least temporarily, before bad side-effects kicked in. Covid also causes fronto-temporal hypoperfusion, restriction of blood flow to the front part of the brain, where mood is regulated. This is also a key mechanism in the cause of strokes and dementia, two other conditions that have taken off since Covid.