Iliyan Ivanov, Nadza Dzinalija, Yoshinari Abe, Pino Alonso, Stephanie H Ameis, Paul D Arnold, Justin T Baker, Srinivas Balachander, Nerisa Banaj, Nuria Bargalló, Marcelo C Batistuzzo, Francesco Benedetti, Jan C Beucke, Irene Bollettini, Brian P Brennan, Jan Buitelaar, Rosa Calvo, Yuqi Cheng, Christopher Rk Ching, Kang Ik K Cho, Sara Dallaspezia, Damiaan Denys, Juliana B Diniz, Benjamin A Ely, Sonia Ferreira, Jamie D Feusner, Kate D Fitzgerald, Martine Fontaine, Patricia Gruner, Greg Hanna, Yoshiyuki Hirano, Marcelo Q Hoexter, Hao Hu, Chaim Huijser, Neda Jahanshad, Anthony James, Fern Jaspers-Fayer, Hongyan Jiang, Melody Jy Kang, Norbert Kathmann, Christian Kaufmann, Minah Kim, Kathrin Koch, Jun Soo Kwon, Luisa Lázaro, Yanni Liu, Christine Lochner, Rachel Marsh, Ignacio Martínez-Zalacaín, David Mataix-Cols, José M Menchón, Luciano Minuzzi, Astrid Morer, Pedro Morgado, Jill Naaijen, Akiko Nakagawa, Janardhanan C Narayanaswamy, Erika L Nurmi, Sanghoon Oh, Chris Perriello, Mary L Phillips, John C Piacentini, Maria Picó-Pérez, Fabrizio Piras, Federica Piras, Yc Janardhan Reddy, Daniela Rodríguez-Manrique, Yuki Sakai, Eiji Shimizu, H Blair Simpson, Noam Soreni, Carles Soriano-Mas, Emily R Stern, Michael C Stevens, S Evelyn Stewart, Philip R Szeszko, Jinsong Tang, Sophia Thomopoulos, David F Tolin, Ysbrand D van der Werf, Guido A van Wingen, Daniela Vecchio, Dick J Veltman, Ganesan Venkatasubramanian, Susanne Walitza, Zhen Wang, Anri Watanabe, Xiufeng Xu, Je-Yeon Yun, Mojtaba Zarei, Fengrui Zhang, ENIGMA-OCD Working Group, Paul M Thompson, Dan J Stein, Odile A van den Heuvel, Joseph O'Neill
MRI studies have revealed structural brain abnormalities in obsessive-compulsive disorder (OCD). Less is known about how age and medication influence them. We analyzed cortical thickness (CT) data from the ENIGMA-OCD Consortium, the world's largest OCD MRI database (46 datasets from 35 centers). Subjects comprised 2057 healthy controls, 1167 unmedicated individuals with OCD, and 1073 individuals with OCD taking one or more psychiatric medications at time of scan. Using a harmonized FreeSurfer protocol, each MRI was parcellated into 68 cortical regions. Linear mixed models controlling for site and symptom severity mapped associations of OCD diagnosis and medication-any psychiatric medication and the medication classes serotonin-reuptake inhibitors (SRIs), tricyclics, antipsychotics, and benzodiazepines-on CT and their interaction with age in each region. Findings surviving FDR-correction included: 1) Unmedicated OCD participants showed thicker cortex and/or lesser CT decrease with age than controls in precentral, inferior parietal, superior parietal, and superior temporal regions (p < .001-.002); 2) In several regions, OCD participants taking any medication had thinner cortex than unmedicated; negative associations of age with CT were similar to controls (p < .001-.005). 3) Findings for SRIs resembled those in for any psychiatric medication. 4) CT was lower in participants taking benzodiazepines than in unmedicated participants in 30 regions (p < .001-.014). No associations of CT involving tricyclics or antipsychotics survived FDR-correction. Commonly prescribed OCD drugs may influence CT in ways that vary with cortical region and medication class. Potential mechanisms are discussed.