A Review on P300 in Obsessive-Compulsive Disorder

Abstract

Neuropsychological studies indicate the presence of cognitive changes in patients with obsessive-compulsive disorder (OCD). Indeed, OCD may be included among the dysfunctions of the frontal lobes and their connections with the limbic system, associative cortex, and basal ganglia. P300 is a positive component of the human event-related potential (ERP); it is associated with processes of encoding, identification, and categorization constituting, as a whole, the superior cortical function of information processing. Thus, P300 explores several areas that are implicated in OCD pathophysiology. Our aim is to review all relevant studies on the P300 component of the human ERP in order to recognize any significant central nervous system (CNS) correlate of cognitive dysfunction in OCD. A PubMed-based literature search resulted in 35 articles assessing P300 in OCD and reporting neurophysiological correlates of response inhibition, cortical hyperarousal, and over-focused attention. A decreased P300 amplitude was reported in both adult and pediatric patients, with a trend toward normalization after pharmacological treatment. Source localization studies disclosed an association between P300 abnormalities and the functioning of brain regions involved in the pathophysiology of OCD. Moreover, studies converge on the evidence of neurophysiological dysfunction in the frontal areas with impairment of the normal inhibitory processes in OCD. At least some of these electrophysiological correlates might reflect the obsessive thoughts and compulsions that characterize this disorder. These findings may also support cognitive-behavioral therapy (CBT) approaches on over-focused attention and inflexibility of compulsive behaviors, which should be associated to pharmacological treatment in these patients.

Comparing the ‘When’ and the ‘Where’ of Electrocortical Activity in Patients with Tourette Syndrome, Body-Focused Repetitive Behaviors, and Obsessive Compulsive Disorder

“…It may be uneasy to reconcile these two theories, given that many studies report opposite results. As proposed in a review, the differences noted across studies may be explained by the severity of OCD symptoms, where greater severity is linked to a decrease in the amplitude of the P300 [117], which could feature the impact of OCD symptoms on processes mediated through the prefrontal cortical regions, which are hypothesized to be involved in memory inhibition mechanisms [118]. Moreover, Thibault et al [43] observed that a higher severity level correlates with a more significant decrease in the P300 component.…”

“…Moreover, Thibault et al [43] observed that a higher severity level correlates with a more significant decrease in the P300 component. Thus, it is plausible that the decrease in P300 is caused by greater symptom severity, whereas the increase in P300 is observed more in patients with less severe symptoms [117].…”

Event‐related EEG synchronization and desynchronization in patients with obsessive–compulsive disorder

“…Neuropsychological studies indicate that patients with OCD may present impairments in cognitive control functions involving executive control, information coding, motor and cognitive inhibition, and processing speed (Raggi et al, 2021). Neuroimaging studies associated these impairments with disturbances in brain networks including the PFC, the SMA, basal ganglia, the subthalamic nucleus and the inferior parietal lobe (Carlisi et al, 2017; Warren et al, 2013), which led to the hypothesis of cortico‐striato‐thalamo‐cortical pathways dysregulation in OCD (Carlisi et al, 2017; Milad & Rauch, 2012; Norman et al, 2016).…”

Identifying emotional components of event-related potentials in the brain functioning of individuals with contamination obsessions and comparison with healthy control group

“…The authors suggested that this increase in P3 amplitude may be related to alterations in cognitive processing in OCD, particularly in the context of attention and stimulus evaluation. Increased P3 amplitude in OCD patients may suggest that they are allocating more attentional resources to certain stimuli, which may contribute to the excessive repetitive behaviors and intrusive thoughts characteristic of the disorder ( Chang et al, 2013 ; Raggi et al, 2021 ). Some studies investigated the brain response to cholecystokinin-tetrapeptide (CCK-4), a compound that induces panic attacks in susceptible individuals, in patients with OCD and healthy control groups.…”