Ms. A had acute marked worsening in mood and obsessions 6 hours before the onset of sore throat, headache, myalgias, and fever. The next day, phonic tics and obsessions markedly increased. Two days later, both Ms. A and her psychiatrically healthy 9-year-old daughter, also experiencing sore throat and fever, had positive rapid streptococcal tests, and Ms. A began a regimen of amoxicillin. When she was nearly afebrile 2 days after that, she experienced her first-ever panic attack, with palpitations, air hunger, chest pressure, and fear of impending doom lasting minutes. The next day, her obsessions, vocal tics, and mood began to improve. One week later, all symptoms decreased to prior levels. Ms. A’s psychotropic medication remained unchanged throughout this episode.