The tics started when Jessica Huitson was only 12 years old. Over time, her condition worsened until she was having whole-body fits and being rushed to hospital. But her local hospital, in Durham, England, was dismissive, suggesting she had anxiety, a mental health condition, and that she was probably spending too much time watching videos on TikTok. Her mother describes the experience as “belittling”. In fact, Jessica had an autoimmune condition brought on by a bacterial infection with streptococcus. The condition is known as paediatric autoimmune neuropsychiatric disorders associated with streptococcus (Pandas). When the infection was identified and treated, her symptoms finally began to improve.

Jessica is not alone in having a dysfunction in the brain mistaken for one in the mind. Evidence is accumulating that an array of infections can, in some cases, trigger conditions such as obsessive-compulsive disorder, tics, anxiety, depression, and even psychosis. And infections are only a small piece of the puzzle. It is increasingly clear that inflammatory disorders and even metabolic conditions can also have sizeable effects on mental health, though psychiatrists rarely look for them. All this is symptomatic of large problems in psychiatry.