Authors: Cees J. Weeland; Selina Kasprzak; Niels T. de Joode; Yoshinari Abe; Pino Alonso; Stephanie H. Ameis; Alan Anticevic; Paul D. Arnold; Srinivas Balachander; Nerisa Banaj; Nuria Bargallo; Marcelo C. Batistuzzo; Francesco Benedetti; Jan C. Beucke; Irene Bollettini; Vilde Brecke; Silvia Brem; Carolina Cappi; Yuqi Cheng; Kang Ik K. Cho; Daniel L. C. Costa; Sara Dallaspezia; Damiaan Denys; Goi Khia Eng; Sónia Ferreira; Jamie D. Feusner; Martine Fontaine; Jean-Paul Fouche; Rachael G. Grazioplene; Patricia Gruner; Mengxin He; Yoshiyuki Hirano; Marcelo Q. Hoexter; Chaim Huyser; Hao Hu; Fern Jaspers-Fayer; Norbert Kathmann; Christian Kaufmann; Minah Kim; Kathrin Koch; Yoo Bin Kwak; Jun Soo Kwon; Luisa Lazaro; Chiang-shan R. Li; Christine Lochner; Rachel Marsh; Ignacio Martínez-Zalacaín; David Mataix-Cols; Jose M. Menchón; Luciano Minnuzi; Pedro Silva Moreira; Pedro Morgado; Akiko Nakagawa; Takashi Nakamae; Janardhanan C. Narayanaswamy; Erika L. Nurmi; Ana E. Ortiz; Jose C. Pariente; John Piacentini; Maria Picó-Pérez; Fabrizio Piras; Federica Piras; Christopher Pittenger; Y. C. Janardhan Reddy; Daniela Rodriguez-Manrique; Yuki Sakai; Eiji Shimizu; Venkataram Shivakumar; Helen Blair Simpson; Noam Soreni; Carles Soriano-Mas; Nuno Sousa; Gianfranco Spalletta; Emily R. Stern; Michael C. Stevens; S. Evelyn Stewart; Philip R. Szeszko; Jumpei Takahashi; Tais Tanamatis; Jinsong Tang; Anders Lillevik Thorsen; David Tolin; Ysbrand D. van der Werf; Hein van Marle; Guido A. van Wingen; Daniela Vecchio; G. Venkatasubramanian; Susanne Walitza; Jicai Wang; Zhen Wang; Anri Watanabe; Lidewij H. Wolters; Xiufeng Xu; Je-Yeon Yun; Qing Zhao; ENIGMA OCD Working Group; Tonya White; Paul M. Thompson; Dan J. Stein; Odile A. van den Heuvel; Chris Vriend · Research
How Does the Thalamus Differ in People with Obsessive-Compulsive Disorder?
A large brain imaging study reveals how the thalamus differs in people with obsessive-compulsive disorder across different age groups.
Source: Weeland, C. J., Kasprzak, S., de Joode, N. T., Abe, Y., Alonso, P., Ameis, S. H., ... & Vriend, C. (2022). The thalamus and its subnuclei —a gateway to obsessive-compulsive disorder. Translational Psychiatry, 12(1), 70. https://doi.org/10.1038/s41398-022-01823-2
What you need to know
- The thalamus, a region deep in the brain, shows different patterns of size in people with obsessive-compulsive disorder (OCD) compared to those without OCD.
- In children with OCD under age 12, the thalamus tends to be larger overall.
- In adults with OCD, the thalamus and its subregions tend to be smaller overall.
- These size differences appear to be influenced by both age and medication use.
- Understanding how brain structure differs in OCD may help improve diagnosis and treatment in the future.
The thalamus and its role in OCD
Obsessive-compulsive disorder (OCD) is a mental health condition that affects about 1-2% of people worldwide. People with OCD experience unwanted, intrusive thoughts (obsessions) and feel compelled to perform repetitive behaviors or mental acts (compulsions) to relieve their anxiety.
Scientists have long been interested in understanding how the brains of people with OCD may differ from those without the disorder. One brain region of particular interest is the thalamus. The thalamus is located deep in the center of the brain and acts as a relay station, passing information between different brain areas. It plays an important role in functions like attention, emotions, and motor control - all of which can be affected in OCD.
Previous smaller studies have found that the thalamus may be larger in children with OCD, but results in adults have been mixed. This new study aimed to get a clearer picture by examining thalamus size across different age groups in a very large sample of people with and without OCD.
A global effort to study the OCD brain
This study was conducted by the ENIGMA OCD Working Group - a collaboration of researchers from 29 research institutes around the world. They pooled brain MRI scans and clinical data from 5,423 people, including 2,678 individuals with OCD and 2,746 healthy controls without OCD.
The researchers used advanced brain imaging analysis techniques to measure the overall volume of the thalamus, as well as the size of five subregions within the thalamus. They compared these measurements between people with and without OCD, looking at children (under 12 years), adolescents (12-17 years), and adults (18+ years) separately.
Key findings across age groups
The study revealed some intriguing differences in thalamus size between people with OCD and healthy controls:
Children (under 12 years):
- Children with OCD tended to have a larger overall thalamus volume compared to children without OCD.
- The lateral region of the thalamus showed the biggest size difference, being significantly larger in children with OCD.
- These size differences were most apparent in unmedicated children with OCD.
Adolescents (12-17 years):
- No significant differences in thalamus size were found between adolescents with and without OCD.
Adults (18+ years):
- Adults with OCD had smaller overall thalamus volume compared to adults without OCD.
- All five subregions of the thalamus tended to be smaller in adults with OCD.
- The anterior (front) region of the thalamus showed the most pronounced size difference.
- These size differences were most apparent in adults taking medication for OCD and those whose OCD started in adulthood.
What might explain these differences?
The researchers propose a few possible explanations for why thalamus size appears to differ in OCD, and why the pattern changes from childhood to adulthood:
Neurodevelopmental differences: The larger thalamus seen in children with OCD may reflect altered brain development early in life. This could potentially predispose someone to developing OCD.
Effects of having OCD: The smaller thalamus volumes seen in adults with OCD may be a result of having the disorder over many years. Chronic stress or overactivity in certain brain circuits could potentially lead to shrinkage over time.
Medication effects: The fact that size differences were most apparent in medicated adults suggests that OCD medications may influence thalamus structure. However, it’s also possible that those taking medication have more severe OCD, which could be the real driver of brain differences.
Age-related changes: The normal process of brain maturation and aging may interact with OCD in complex ways, leading to different patterns at different life stages.
It’s important to note that this study looked at group averages - not all individuals with OCD will show these exact brain differences. Brain structure varies widely from person to person.
Implications and future directions
This study provides the most comprehensive look yet at how the thalamus may differ in people with OCD across the lifespan. The findings suggest that OCD is associated with widespread changes to the thalamus, rather than being limited to one specific subregion.
Understanding these structural brain differences may eventually help improve diagnosis and treatment of OCD. For example, brain scans might one day be used alongside other tools to help identify OCD risk in children. Or, they may help predict which treatments will work best for a particular individual.
However, we’re still a long way from using brain scans in this way. More research is needed to understand exactly how and why these structural differences arise, and how they relate to OCD symptoms.
Future studies should:
- Follow people over time to see how thalamus structure changes as OCD develops
- Look at how different OCD medications influence brain structure
- Examine how thalamus structure relates to specific OCD symptoms
- Combine structural imaging with other techniques to understand how the function of the thalamus may be altered in OCD
By building on these findings, researchers hope to gain a deeper understanding of the brain mechanisms underlying OCD. This knowledge may ultimately lead to better ways to prevent, diagnose, and treat this challenging disorder.
Conclusions
- The thalamus shows different size patterns in people with OCD compared to those without OCD.
- These differences vary by age - larger in children with OCD, but smaller in adults with OCD.
- Medication use appears to influence thalamus size in people with OCD.
- More research is needed to understand how these structural differences relate to OCD symptoms and treatment.