Medical Condition

OCD imposes significant psychological, social, and economic burdens on affected individuals and their families. When associated with infectious or immune processes, the condition may have a more severe and fluctuating course, necessitating early identification and multidisciplinary management. Expanding awareness among clinicians of infection-associated OCD variants is critical for improving outcomes and advancing research into targeted immunotherapies.

Obsessive-Compulsive Disorder (OCD) is characterized by persistent, intrusive thoughts (obsessions) and repetitive, ritualistic behaviors or mental acts (compulsions) aimed at reducing distress or preventing perceived harm. These symptoms often lead to significant functional impairment and distress. Patients may exhibit contamination fears, symmetry compulsions, taboo or intrusive thoughts, moral scrupulosity or checking behaviors. The disorder may manifest in childhood, adolescence, or early adulthood, with symptom severity ranging from mild to severe.

OCD affects approximately 2% of the global population, with onset typically occurring before age 25. Twin studies and family aggregation analyses have revealed substantial heritability, estimated at 40–50% in children and 27–45% in adults. Genetic studies have identified risk loci near genes involved in glutamatergic transmission, synaptic plasticity, and immune modulation. Family history of OCD or other anxiety spectrum disorders significantly increases the risk for first-degree relatives.

OCD often coexists with other neuropsychiatric disorders, including tic disorders, attention-deficit/hyperactivity disorder (ADHD), anxiety disorders, and major depressive disorder. Neuroimaging studies implicate hyperactivity within cortico-striato-thalamo-cortical (CSTC) circuits, particularly involving the orbitofrontal cortex, anterior cingulate cortex, and striatum. Functional abnormalities in these networks are thought to underlie deficits in error detection, cognitive flexibility, and inhibitory control seen in OCD patients.

In infectious or post-infectious presentations, inflammatory markers may be elevated, and neuroimaging occasionally reveals basal ganglia changes consistent with neuroinflammatory processes.

The pathogenesis of OCD is multifactorial, involving neurodevelopmental, immunological, genetic, and environmental factors. In classical OCD, dysfunction of the CSTC circuitry and imbalances in neurotransmitter systems—especially serotonin, dopamine, and glutamate—are central. In immune-mediated OCD, such as in PANS/PANDAS, an autoimmune response misdirected toward neural tissue is hypothesized to result in neuroinflammation and neuronal dysfunction.

Experimental studies have demonstrated anti-neuronal autoantibodies in a subset of children with OCD, supporting a link between peripheral immune dysregulation and central nervous system involvement (Murphy et al., 2012).

Standard treatment of OCD includes cognitive-behavioral therapy (CBT), particularly exposure and response prevention (ERP), and pharmacotherapy targeting serotonin reuptake. In immune-mediated cases, adjunctive therapies may include immunomodulatory treatments such as corticosteroids, or non-steroidal anti-inflammatory agents, Antibiotic therapy may be considered in acute post-infectious presentations but should be guided by clinical and laboratory findings.

For more severe cases, intravenous immunoglobulin (IVIG), may be used as an immunomodulatory treatment,  although this remains investigational and is typically reserved for severe, treatment-resistant cases. Antibiotic therapy may be considered in acute post-infectious presentations but should be guided by clinical and laboratory findings.

Multidisciplinary evaluation, including neurology, immunology, and psychiatry, is often necessary for optimal management.

Key mechanisms implicated in OCD pathophysiology include:

• Dysregulation of CSTC circuits
• Neurotransmitter imbalances, particularly serotonin and glutamate
• Immune dysregulation and autoimmunity (notably in PANS/PANDAS)
• Neuroinflammation and microglial activation
• Blood-brain barrier compromise following infection

These factors interact in a dynamic, potentially self-reinforcing loop, particularly when the disease is initiated or aggravated by infectious processes.

OCD is a complex neuropsychiatric disorder with well-established neurobiological underpinnings. However, in certain cases—particularly in children—the emergence of symptoms following infection suggests an immune-mediated pathophysiology that challenges traditional models. Recognition of these distinct subtypes is essential for accurate diagnosis and tailored treatment approaches.

Ayşegül, E. (2022, October 14). SARS-CoV-2/COVID-19 associated pediatric acute-onset neuropsychiatric syndrome: A case report of female twin adolescents. Psychiatry Research Case Reports, 1(2), 100074. https://doi.org/10.1016/j.psycr.2022.100074

Frankovich, J., Swedo, S., Murphy, T., Dale, R., Agalliu, D., Williams, K., Daines, M., Hornig, M., Chugani, H., Sanger, T., Muscal, E., Pasternack, M., Cooperstock, M., Gans, H., Zhang, Y., Cunningham, M., Bernstein, G., Bromberg, R., Willett, T., Brown, K., Farhadian, B., Chang, K., Geller, D., Hernandez, J., Sherr, J., Shaw, R., Latimer, E., Leckman, J. F., & Thienemann, M. (2017). Clinical management of pediatric acute-onset neuropsychiatric syndrome: Part I—psychiatric and behavioral interventions. Journal of Child and Adolescent Psychopharmacology, 27(7), 566–573. https://doi.org/10.1089/cap.2016.0145

Murphy, T. K., Storch, E. A., Goodman, W. K., & Geffken, G. R. (2012). The immunology of obsessive-compulsive disorder. Psychiatric Clinics of North America, 35(1), 123–139. https://doi.org/10.1016/j.psc.2011.11.004

PANDAS Physicians Network. (n.d.). PANDAS Physicians Network. https://pandasppn.org

International OCD Foundation. (n.d.). International OCD Foundation. https://iocdf.org

Swedo, S. E., Leonard, H. L., Garvey, M., Mittleman, B., Allen, A. J., Perlmutter, S., Lougee, L., Dow, S., Zamkoff, J., & Walker, E. (1998). Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections: Clinical description of the first 50 cases. American Journal of Psychiatry, 155(2), 264–271. https://doi.org/10.1176/ajp.155.2.264