Abstract
Objective
To identify regional cerebral blood flow (rCBF) differences between individuals with Obsessive–Compulsive Disorder (OCD) and healthy controls. Mehtods: Healthy controls (n = 81, Mage = 41.9, 53.0% female, 42.0% Caucasian) and persons diagnosed by psychiatric examination with OCD (n = 1020, Mage = 34.8, 33.6% female, 66.3% Caucasian) were selected from a deidentified adult clinical outpatient database. Those with comorbid diagnoses were included. Significant differences (alpha = 0.001) were found for age [t(1099) = −4.4], gender [χ2(2) = 25.7], and race [χ2(12) = 30.1] between groups and therefore were controlled for. Significant rCBF differences were noted in the cerebellum [left:F(1,1096) = 21.6; right:F(1,1096) = 18.3], limbic system [left:F(1,1096) = 12.2; right:F(1,1096) = 10.4], and basal ganglia [left:F(1,1096) = 18.6; right:F(1,1096) = 18.3].
Results
Group means comparisons indicated higher perfusion in the cerebellum for the OCD group. Lower perfusion was found in the limbic system and basal ganglia in the OCD group. This study found higher perfusion in the cerebellum among the OCD group. Previous research found increased rCBF in the left cerebellum in OCD before pharmacotherapy. In the right cerebellum, increased rCBF was found among participants with early-onset OCD.
Conclusion
Overall, there is limited research on the cerebellum because of its use as a reference point. No research was found regarding the limbic system in OCD using SPECT; however, other neuroimaging found increased amygdala reactivity to emotional face stimuli. This study found lower perfusion in the basal ganglia among the OCD group. Previous research found hypoperfusion in the right; however, hypoperfusion in the left was not significant. Updated OCD and rCBF research with SPECT are needed. Limitations included the inclusion of comorbidities and use of DSM-IV-TR rather than DSM-5 diagnosis criteria.
Venous blood ammonia can be associated with cerebral blood flow in hepatic encephalopathy
