Dissociable source-monitoring impairments in obsessive–compulsive disorder and schizophrenia

Abstract

Background: Based on the observed clinical overlap between obsessive–compulsive disorder (OCD) and schizophrenia (SCZ), both conditions may share, at least in part, common cognitive underpinnings. Among the cognitive deficits that could be involved, it has been hypothesized that patients share a failure in their abilities to monitor their own thoughts (source monitoring), leading to confusion between what they actually did or perceived and what they imagined. Although little is known regarding source-monitoring performances in patients with OCD, numerous studies in patients with SCZ have observed a relationship between delusions and/or hallucinations and deficits in both internal source- and reality-monitoring abilities. Methods: The present work compared source-monitoring performances (internal source and reality monitoring) between patients with OCD (n = 32), patients with SCZ (n = 38), and healthy controls (HC; n = 29). Results: We observed that patients with OCD and patients with SCZ displayed abnormal internal source-monitoring abilities compared to HC. Only patients with SCZ displayed abnormalities in reality monitoring compared to both patients with OCD and HC. Conclusions: Internal source-monitoring deficits are shared by patients with OCD and SCZ and may contribute to the shared cognitive deficits that lead to obsessions and delusions. In contrast, reality-monitoring performance seems to differentiate patients with OCD from patients with SCZ.

Understanding source monitoring subtypes and their relation to psychosis: a systematic review and meta‐analysis

“…2b). 9,23–66 A detailed description of the exclusion reasons of the 54 excluded studies is available in eTable 4.…”

“…Conversely, no SM deficits have been reported for conditions where self is preserved, such as major depressive disorder. 34 However, deficits in ISM, but not RM, have been also encountered in patients with obsessive-compulsive disorder, 47 requiring caution in interpreting SM findings as specific for self-disturbances until replicated results from cross-diagnostic studies are available.…”

Similarities and Differences in Brain Activation Between Patients With Schizophrenia and Obsessive-Compulsive Disorder: A Near-Infrared Spectroscopy Study

“…A study found that both SZ and OCD showed impaired internal source-monitoring abilities, and compared to patients with OCD, patients with SZ had abnormal reality monitoring. These patients all have difficulty tracking their own minds, which causes them to be confused about what they actually did or interpreted and what they envisioned ( 6 ). In conclusion, the results we obtained by NIRS may help us better understand the characteristics of cognitive deficits and insight in SZ and OCD.…”

Altered Resting-State Brain Activity in Schizophrenia and Obsessive-Compulsive Disorder Compared With Non-psychiatric Controls: Commonalities and Distinctions Across Disorders

“…SCZ is characterized by consciousness abnormalities including hallucinations, delusions, disorganized speech, decreased motivation, and cognitive deficits (12), while OCD is identified by recurrent intrusive and unwanted thoughts, which result in distress or anxiety and repetitive behaviors (13). The obsessive thoughts in both OCD and delusional ideas in SCZ involved intrusive, unwanted, and foreign thoughts, which indicated the shared failure in monitoring their own thoughts (14). Meta-analysis showed that the total prevalence rate of OCD in SCZ was as high as 12.3% (15).…”

“…The diagnosis of OCD also increases the risk of SCZ (16). Patients with both disorders showed deficient response inhibition (17) and internal source-monitoring deficits (14). As for etiology researches, the common features of the two disorders can be partially explained by shared polygenic risk (8) and shared pathways of glutamate, dopamine, and serotonin (9).…”