Effect of Lithium Therapy on Long COVID Symptoms

1. Documented or self-reported positive test for COVID-19 ≥4 weeks prior to enrollment. 2. No fever for ≥4 weeks prior to enrollment. 3. Reports fatigue and/or brain fog (i.e. concentration or memory impairment) for ≥4 weeks prior to enrollment on the PASC-Specific Symptom questionnaire beginning after infection with COVID-19. 4. Fatigue Severity Scale (FSS) score ≥28 or Brain Fog Severity Scale (BFSS) score ≥28 at baseline. 5. Beck Depression Inventory II score \<24. 6. No change in any psychoactive or steroid medications for ≥30 days. 7. No plan to change any psychoactive, steroid or diuretic medication for ≥5 weeks and not planning on obtaining a COVID vaccine within the next 5 weeks. 8. Not using any long COVID therapies felt to be worsening the patient's symptoms or starting a long COVID therapy within the next 5 weeks. 9. No history of fibromyalgia, chronic fatigue syndrome or progressive cognitive disorder prior to COVID-19 infection. 10. No active medical, psychiatric or social problems that would interfere with completing the study procedures in the opinion of the investigator. 11. No use of tobacco or marijuana products for \>6 months and no current alcohol abuse (≥4 drinks/day) or illicit drug use. 12. Not receiving or applying for disability payments or workman's compensation for long COVID. 13. Not pregnant or nursing or planning to get pregnant over the next two months.