What is (really) Tourette's syndrome, which Robbie Williams claims to have?

Robbie Williams, the 51-year-old British singer, revealed this weekend that he suffers from Tourette syndrome. Tourette syndrome is a neurological disorder, not a psychiatric one. It's a disorder of communication between neurons at the cellular level. No abnormalities are visible on MRI, but there is disinhibition in certain brain circuits.

It manifests itself through tics (not to be confused with OCD). These tics are sudden, rapid, involuntary, and repetitive movements or sounds. Blinking, shrugging, grimacing, small noises, sniffing, throat clearing. These tics can worsen with stress, fatigue, or depression.

But Robbie Williams has never spoken about tics. The singer explains that he has no motor or vocal tics. He says he suffers from intrusive thoughts, which he calls "an inside Tourette's."

In reality, what he describes sounds much more like OCD, obsessive-compulsive disorder. OCD is an anxiety disorder, consisting of intrusive, distressing, absurd thoughts, and/or compulsions: mental gestures or rituals performed to reduce anxiety.

Among the classic OCDs, the fear of contamination, the person washes their hands constantly. This is cleanliness OCD. There is also constant doubt, the person checks again and again whether they have properly closed their door, for example, this is verification OCD. And there is the fear of involuntarily causing harm, this is aggressive OCD.

What Robbie Williams is describing doesn't appear to be Tourette's. He has no visible tics, so he doesn't have Tourette's in the medical sense. But he may have an obsessive-compulsive disorder, with repetitive and intrusive thoughts.