Catching Insanity: A controversial disease revives the debate about the immune system and mental illness

Isak’s illness dragged on 4 years. The year before his meltdowns, his brother had 4 strep infections. In September 2013, 3 1/2 years after his 1st tics appeared, a Boston pediatric infectious-disease specialist put Isak on azithromycin (antibiotic used to treat food poisoning, ear infections, and  strep throat).

Isak’s crippling fear vanished within days; he stopped grunting. Less than a week after starting his son on the antibiotic, Isak smiled for the 1st time in 4 years; the tantrums that had held the family hostage for years faded away.

As doctors return to a holistic understanding of the relationship between body and brain, they are gaining new treatments for terrifying illnesses. Knowing that at least some mental disorders are caused by infection puts a new set of tools at doctors’ disposal.