When activist John Davidson shouted a racial slur at the Bafta Awards in February, the room went quiet. Those who did not know him assumed the worst. Those who did, knew better.

Davidson, a Tourette syndrome activist and executive producer of the film “I Swear”, had not chosen those words. His condition had.

The involuntary outburst, broadcast to millions on the BBC, thrust Tourette syndrome into the spotlight in the most uncomfortable of circumstances.

It has also reignited a long-overdue conversation about how little the public truly understands a condition that has shaped the lives of many people around the world.

Tourette or Tourette's, is a neurodevelopmental condition linked to...