A Double-Blind Randomized Placebo-Controlled Pilot Study of Azithromycin in Youth with Acute-Onset Obsessive–Compulsive Disorder

Sudden and severe onset of obsessive-compulsive disorder (OCD) may present secondary to infectious and/or immune-mediated triggers. We assessed the preliminary efficacy, tolerability, and safety of azithromycin compared with placebo in the treatment of OCD and associated symptoms in children with pediatric acute-onset neuropsychiatric syndrome (PANS).Thirty-one youth aged 4-14 years (M = 8.26 ± 2.78 years, 62.5% male) were randomized to receive either placebo or azithromycin for 4 weeks (10 mg/kg up to 500 mg per day). Both groups were administered twice daily probiotics. The primary outcome, obsessive-compulsive symptom severity, was assessed using the OCD Clinical Global Impressions Severity (CGI-S OCD) and Children's Yale-Brown Obsessive Compulsive Scale (CY-BOCS).Participants in the azithromycin group (n = 17) showed significantly greater reductions in OCD severity on the CGI-S OCD than the placebo group (n = 14) posttreatment (p = 0.003), although there were no significant differences on the CY-BOCS. Significantly more participants in the azithromycin condition met treatment responder criteria on the CGI-I OCD at the end of week 4 (41.2%, n = 7) in comparison to the placebo group (7.1%, n = 1; p = 0.045). Tic severity moderated treatment response, with greater tic severity being associated with enhanced treatment response on the CGI-S OCD. Azithromycin was well tolerated with minimal adverse effects and no study dropouts due to side effects. However, the azithromycin group showed a trend toward significantly greater electrocardiography QTc (p = 0.060) at the end of week 4, and significantly more reports of loose or abnormal stools (p = 0.009).This double blind pilot study suggests that azithromycin may be helpful in treating youth meeting the PANS diagnosis, especially those with elevated levels of both OCD and tic symptoms. Azithromycin was well tolerated, but the potential for cardiac risks suggests that additional monitoring may be needed to ensure safety.