Altered prefrontal beta oscillatory activity during removal of information from working memory in obsessive-compulsive disorder

BACKGROUND

Obsessive-compulsive disorder (OCD) is related to working memory impairment. Since patients with OCD have difficulty controlling their obsessive thoughts, removal of irrelevant information might be important in the pathophysiology of OCD. However, little is known about brain activity during the removal of information from working memory in patients with OCD. Our goal was to explore potential deficits in inhibitory function related to working memory processes in patients with OCD.

METHODS

Sixteen OCD patients and 20 healthy controls (HCs) were recruited. We compared in prefrontal alpha and beta band activity derived from magnetoencephalography (MEG) between patients with OCD and HCs during multiple phases of information processing associated with working memory, especially in post-trial period of the visuospatial working memory task (the delayed matching-to-sample task), which is presumed to be related to the information removal process of working memory.

RESULTS

Prefrontal post-trial beta power change (presumed to occur at high levels during the post-trial period) exhibited significant reductions in patients with OCD compared to HCs. In addition, the post-trial beta power change was negatively correlated with Obsessive-Compulsive Inventory-Revised total scores in patients with OCD.

CONCLUSIONS

These findings suggest that impairment in the removal of information from working memory might be a key mechanism underlying the inability of OCD patients to rid themselves of their obsessions.

Core clinical symptoms and suicidal ideation in patients with obsessive-compulsive disorder: A network analysis

INTRODUCTION

Suicidality in obsessive-compulsive disorder (OCD) is underestimated and it is important for clinicians to understand the factors that contribute to suicidal ideation. The present study aimed to estimate a network of the core clinical symptoms of OCD including obsessions, compulsions, and obsessive-compulsive (OC) symptom dimensions, depressive symptoms, and psychological traits, and to examine which symptoms contribute to suicidal ideation in patients with a primary diagnosis of obsessive-compulsive disorder.

METHODS

A total of 444 patients with OCD were assessed with the Yale-Brown Obsessive-Compulsive Scale, the Montgomery-Asberg Depression Rating Scale, and various other measures. Network analysis was conducted to estimate the network of obsessive-compulsive and depressive symptoms, psychological traits including alexithymia and impulsivity, and demographic covariates. Symptoms directly related to suicidal ideation in the network were examined for their relative contribution to suicidal ideation.

RESULTS

Suicidal ideation was directly related to degree of control over compulsive behaviors, distress associated with compulsive behaviors, time spent performing compulsive behaviors, and unacceptable thoughts, along with depressive symptoms and alexithymia. In the network of OC and depressive symptoms the most central symptoms among the former were interference due to compulsive behaviors and interference due to obsessive thoughts, and among the latter were pessimistic thoughts and reported sadness.

CONCLUSION

The findings suggest that along with depressive symptoms and alexithymia, compulsions and unacceptable thoughts dimension may contribute to suicidality, and thus, should be carefully monitored in patients with OCD.

Use of serotonin reuptake inhibitors and risk of subsequent bone loss in a nationwide population-based cohort study

This study examined whether the use of SRIs is associated with an increased risk of bone loss using a nested case-control design with a nationwide population-based cohort in Korea. Using the Korean National Health Screening Cohort, subjects newly diagnosed with osteoporosis or osteopenia (n = 55,799) were matched with controls (n = 278,995) at a ratio of 1:5. We stratified the participants by their time-dependent use of SRIs and sex and controlled for various confounders, including lifestyle habits, laboratory data, and comorbidities. Conditional logistic regression showed that both recent and former users of SRIs had an increased risk of subsequent bone loss compared with non-users: men [recent users: odds ratio (OR) 1.35, 95% confidential interval (CI) 1.20, 1.53; former-users: OR 1.10, 95% CI 1.01, 1.20]; women (recent users: OR 1.38, 95% CI 1.28-1.48; former-users: OR 1.07, 95% CI 1.02, 1.21). The use of SRIs was associated with an increased risk of bone loss in both men and women. In particular, the association was stronger in recent users. These findings provide population-level evidence for the risk of bone loss associated with SRI exposure and highlight the importance of monitoring the bone health of SRI users.

Possible Association of the Ubiquitin-Specific Peptidase 46 Gene (USP46) with Affective Temperamental Traits in Healthy Korean Volunteers

OBJECTIVE

Ubiquitin-specific peptidase 46 gene (USP46) polymorphisms is part of ubiquitin-proteasome system, which is responsible for dynamic cellular processes such as the regulation of cell cycle. USP46 has been reported to be associated with major depressive disorder. The objective of the present study was to investigate the association of USP46 polymorphisms with affective temperamental traits in healthy subjects.

METHODS

A total of 557 Korean healthy volunteers were recruited, and 545 subjects (328 male, 217 female) were included in the final analysis. The DNA of the subjects was isolated from saliva samples. Two single-nucleotide polymorphisms (SNPs) rs346005, rs2244291 in USP46 were genotyped. Affective temperaments were assessed using the Korean version of Temperament Evaluation of the Memphis, Pisa, Paris, and San Diego Autoquestionnaire (TEMPS-A).

RESULTS

A significant association was found between rs346005 genotypes and TEMPS-A only in male subjects. In particular, subjects with the CC genotype of rs346005 showed a more depressive temperament than subjects with AA or CA genotypes in males. For rs2244291, there were no associations between the rs2244291 genotypes and TEMPS-A scores.

CONCLUSION

Some affective temperaments may serve as a genetic predisposing factors for affective disorders, such as depressive disorder, via vulnerability genes related to the ubiquitin-proteasome system.