OCD and ADHD

00:00 Introduction to the Topic 00:36 Defining OCD 02:10 Overlap of OCD and ADHD 06:41 Similarities in brain regions associated with OCD and ADHD 07:51 Differences in brain regions and activity in OCD vs. ADHD 09:40 Other differences between OCD and ADHD 14:02 The confounding role of CDS, cognitive disengagement syndrome, in the overlap of ADHD with OCD 16:08 Conclusion Here I discuss the overlap of OCD with ADHD and vice versa. After describing the symptoms of OCD, I discuss their degree of overlap with each other. The majority of people having one disorder do NOT have the other. However, the risk of having the other disorder if one has OCD or ADHD is still relatively greater than in the general population. It seems that in those with OCD in childhood, ADHD is the most common comorbidity even though most do not have it. But by teens and adulthood, the rate of ADHD in OCD declines. In contrast, the rate of OCD in people with ADHD is quite low but still possibly more than double the rate of the general population. The disorders share similar underlying brain regions and networks. But the findings for OCD are opposite those for ADHD, with some brain regions being larger and over-active in OCD while being smaller and less active than normal in ADHD. I discuss other differences as well, including neurochemicals, drugs used in treatment, genetic factors, etc. I conclude with a warning that this research is confounded by the fact that CDS, another attention disorder, may actually be the most common attention disorder in OCD and be mistaken as ADHD inattentive presentation. More research is needed. References: Brem, S. et al. (2014). The neurobiological link between OCD and ADHD. ADHD Attention Deficit Hyperactivity Disorder, 6, pp. 175-202. https://link.springer.com/article/10.1007/s12402-014-0146-x Abramovitch, A. et al. (2015). Comorbidity Between Attention Deficit/Hyperactivity Disorder and Obsessive-Compulsive Disorder Across the Lifespan A Systematic and Critical Review. Harvard Review of Psychiatry, 23(4), 245-262. DOI: 10.1097/HRP.0000000000000050 Kilic, S. M. (2020). The Clinical Characteristics of ADHD and Obsessive-Compulsive Disorder Comorbidity. Journal of Attention Disorders, 24(12). https://doi.org/10.1177/1087054716669226