Recently I ran across an article in the Los Angeles Times that may be of interest if you have a child who has suddenly shown symptoms of OCD (Obsessive Compulsive Disorder) or tics. It’s important to state that although the article explores possible connections between strep throat infections and the sudden onset of OCD symptoms, it admits that studies to date aren’t at all conclusive.
The possible connection may have to do with a genetic predisposition to an autoimmune response to the very common strep bacteria, and possibly some other infections as well. The autoimmune response may bind to neurons in the brain and cause the release of unusually high amounts of dopamine and other brain chemicals. Abnormal amounts of dopamine are possibly the cause of tics and OCD symptoms.
If you are interested in following up more on this, read the article and then ask your doctor about Pediatric Autoimmune Neuropsychiatric Disorder, known as PANDAS.