At the time we had the most success with NAC, DS had just been weaned completely from all meds due to side effects. He had been on prescription meds for 2 1/2 years, which helped OCD a bit, but not tics. The meds made him aggressive, negative, hateful, revengeful, etc. Although doctors told me it was coincidental and not from meds. He developed priapism from the meds, and finally we were told to wean him off everything. That is when he started the NAC. Within 3 weeks we had our happy, good-natured child back, after 2 1/2 years of misery. This lasted for 7 glorious months, until he experienced his most severe onset of PANS. Current MD linked this to Miralax use. If your DS has ever used Miralax, I will share the details.