My son is 21 and healthy except he has had muscle twitching for 3 plus months unknown etiology as we have tried eliminating any causative factors. Blood tests reveal no abnormalities - had a Lyme test to rule that out- inconclusive so far hasn t had follow up draws. Causing him to be agitated and difficult to do his studies- junior in college studying business. Has appts lined up with specialists as we continue to seek a proper diagnosis and hopefully treat this condition. On doxycycline 100 mg 2 x a day as a precaution in the event it s Lyme associated