[The role of inhibition in obsessional-compulsive disorders]

Disruption of consciousness depends on insight in OCD and on positive symptoms in schizophrenia

Disruption of conscious access contributes to the advent of psychotic symptoms in schizophrenia but could also explain lack of insight in other psychiatric disorders. In this study, we explored how insight and psychotic symptoms related to disruption of consciousness. We explored consciousness in patients with schizophrenia, patients with obsessive-compulsive disorder (OCD) with good vs. poor insight and matched controls. Participants underwent clinical assessments and performed a visual masking task allowing us to measure individual consciousness threshold. We used a principal component analysis to reduce symptom dimensionality and explored how consciousness measures related to symptomatology. We found that clinical dimensions could be well summarized by a restricted set of principal components which also correlated with the extent of consciousness disruption. More specifically, positive symptoms were associated with impaired conscious access in patients with schizophrenia whereas the level of insight delineated two subtypes of OCD patients, those with poor insight who had consciousness impairments similar to patients with schizophrenia, and those with good insight who resemble healthy controls. Our study provides new insights about consciousness disruption in psychiatric disorders, showing that it relates to positive symptoms in schizophrenia and with insight in OCD. In OCD, it revealed a distinct subgroup sharing neuropathological features with schizophrenia. Our findings refine the mapping between symptoms and cognition, paving the way for a better treatment selection.

Alterations of regional spontaneous brain activity in obsessive-compulsive disorders: A meta-analysis

BACKGROUND

Recent studies using resting-state functional magnetic resonance imaging (rs-fMRI) demonstrate that there is aberrant regional spontaneous brain activity in obsessive-compulsive disorders (OCD). Nevertheless, the results of previous studies are contradictory, especially in the abnormal brain regions and the directions of their activities. It is necessary to perform a meta-analysis to identify the common pattern of altered regional spontaneous brain activity in patients with OCD.

METHODS

The present study conducted a systematic search for studies in English published up to May 2023 in PubMed, Web of Science, and Embase. These studies measured differences in regional spontaneous brain activity at the whole brain level using regional homogeneity (ReHo), the amplitude of low-frequency fluctuations (ALFF) and the fractional amplitude of low-frequency fluctuations (fALFF). Then the Anisotropic effect-size version of seed-based d mapping (AES-SDM) was used to investigate the consistent abnormality of regional spontaneous brain activity in patients with OCD.

RESULTS

27 studies (33 datasets) were included with 1256 OCD patients (650 males, 606 females) and 1176 healthy controls (HCs) (588 males, 588 females). Compared to HCs, patients with OCD showed increased spontaneous brain activity in the right inferior parietal gyrus (Brodmann Area 39), left median cingulate and paracingulate gyri (Brodmann Area 24), bilateral inferior cerebellum, right middle frontal gyrus (Brodmann Area 46), left inferior frontal gyrus in triangular part (Brodmann Area 45) and left middle frontal gyrus in orbital part (Brodmann Area 11). Meanwhile, decreased spontaneous brain activity was identified in the right precentral gyrus (Brodmann Area 4), right insula (Brodmann Area 48), left postcentral gyrus (Brodmann Area 43), bilateral superior cerebellum and left caudate (Brodmann Area 25).

CONCLUSIONS

This meta-analysis provided a quantitative review of spontaneous brain activity in OCD. The results demonstrated that the brain regions in the frontal lobe, sensorimotor cortex, cerebellum, caudate and insula are crucially involved in the pathophysiology of OCD. This research contributes to the understanding of the pathophysiologic mechanism underlying OCD and could provide a new perspective on future diagnosis and treatment of OCD.

The Applicability of Acceptance and Commitment Therapy for Obsessive-Compulsive Disorder: A Systematic Review and Meta-Analysis

Background: Acceptance and commitment therapy (ACT), a third-generation cognitive behavioral therapy (CBT), has proved its efficacy amidst various mental disorders. A growing body of studies has shown that ACT can improve obsessive-compulsive disorder (OCD) severity in recent years. To assess the effect of ACT on OCD, we carried out a systematic review and meta-analysis to provide a basis for therapists to use different psychological dimensions of ACT for OCD. Methods: PubMed, the Cochrane Library, EMBASE, EBSCO Host, and literature references were searched until May 2021. Randomized controlled trials (RCTs) and other study designs assessing the effect of ACT among adults suffering from OCD were examined. Results: Fourteen studies, including 413 participants, published between 2010 and 2021 were identified. ACT made statistically significant progress in the Yale–Brown Obsessive–Compulsive Scale (YBOCS) compared with control conditions. Conclusion: After reviewing all the ACT studies, we acknowledge the plausibility of ACT in treating OCD and improving its symptoms for the clinical population. ACT can also be an adjunct therapy for other well-established treatments. It also favors targeting psychological inflexibility. Further well-controlled and high-quality RCTs are required for a better conclusion in further studies.