Taekwan Kim, BSc; Seoyeon Kwak, PhD; Ji-Won Hur, PhD; Junhee Lee, MD; Won-Gyo Shin, PhD; Tae Young Lee, MD; Minah Kim, MD, PhD; Jun Soo Kwon, MD, PhD
Background: Using biological evidence to define subtypes within the heterogeneous population with obsessive–compulsive disorder (OCD) is important for improving treatment response. Based on age at onset, OCD can be clustered into 2 groups, each of which is more homogeneous with respect to clinical and cognitive phenotype. However, the neural bases for these phenotypic differences need to be established to construct evidence-based homogeneous groups.
Methods: We compared brain volumes, clinical symptoms, and neurocognitive function for 49 people with early-onset OCD and 52 with late-onset OCD (participants in both groups were unmedicated or drug-naïve), and 103 healthy controls. We performed regression analyses to examine group × volume interaction effects on clinical outcomes or neurocognitive function in people with OCD.
Results: We observed larger volumes in the precentral, orbitofrontal, middle frontal, and middle temporal gyri in people with early-onset OCD compared to those with late-onset OCD. Poorer visuospatial construction in early-onset OCD was correlated with a larger left middle frontal gyrus volume. Impaired visuospatial memory in people with early-onset OCD and cognitive inflexibility in people with late-onset OCD were correlated with increased and decreased volume in the left middle frontal gyrus, respectively. We found group × volume interactions for obsessive–compulsive symptom scores in the left middle temporal gyrus of people with OCD.
Limitations: Although we divided the subtypes using the commonly adopted criterion of age at onset, this criterion is still somewhat controversial.
Conclusion: We provided the neural bases for clinical and neurocognitive differences to demonstrate that biological evidence underlies the distinctions between early- and late-onset OCD. This study suggests that different treatment options should be considered for the OCD subtypes, because their neurobiology differs and is related to distinct phenotypic profiles.
Submitted Feb. 10, 2019; Revised June 9, 2019; Accepted July 23, 2019; Published online Nov. 25, 2019
Acknowledgments: The authors thank the families who participated in the study for their availability, as well as the MRI technician at Seoul National University Hospital and the research coordinators at the Clinical Cognitive Neuroscience Centre for their help in recruiting participants and arranging schedules for the study. This research was supported by the Basic Science Research Program and the Basic Research Laboratory Program through the National Research Foundation of Korea (NRF; grant no. 2019R1A2B5B03100844, 2018R1A4A1025891).
Affiliations: From the Department of Brain and Cognitive Sciences, Seoul National University College of Natural Sciences, Seoul, Republic of Korea (T. Kim, Kwak, Kwon); Department of Psychology, Korea University, Seoul, Republic of Korea (Hur); Department of Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea (J. Lee, T.Y. Lee, M. Kim, Kwon); Institute of Human Behavioral Medicine, SNU-MRC, Seoul, Republic of Korea (Shin, T.Y. Lee, Kwon); and Department of Neuropsychiatry, Seoul National University Hospital, Republic of Korea (M. Kim).
Competing interests: None declared.
Contributors: T. Kim, S. Kwak, J.-W. Hur, T.Y. Lee and J.S. Kwon designed the study. T. Kim, S. Kwak and W.-G. Shin acquired the data, which T. Kim, J.-W. Hur, J. Lee, W.-G. Shin, M. Kim and J.S. Kwon analyzed. T. Kim wrote the article, which all authors reviewed. All authors approved the final version to be published and can certify that no other individuals not listed as authors have made substantial contributions to the paper.
Correspondence to: J.S. Kwon, Department of Psychiatry, Seoul National University College of Medicine, 101 Daehak-no, Chongno-gu, Seoul 03080, Republic of Korea; firstname.lastname@example.org