Co-occurrence of schizo-obsessive traits and its correlation with altered executive control network functional connectivity.

The prevalence of obsessive-compulsive symptoms (OCS) in schizophrenia patients is as around 30%. Evidence suggested that mild OCS could reduce symptoms of schizophrenia, supporting the presence of compensatory functions. However, severe OCS could aggravate various impairments in schizophrenia patients, supporting the "double jeopardy hypothesis". Patients with schizo-obsessive comorbidity, schizophrenia patients and obsessive-compulsive disorder patients have been found to have similarities in executive dysfunctions and altered resting-state functional connectivity within the executive control network (ECN). Executive functions could be associated with the ECN. However, little is known as to whether such overlap exists in the subclinical populations of individuals with schizo-obsessive traits (SOT), schizotypal individuals and individuals with high levels of obsessive-compulsive symptoms (OCS). In this study, we recruited 30 schizotypal individuals, 25 individuals with OCS, 29 individuals with SOT and 29 controls for a resting-state ECN-related functional connectivity (rsFC) and a go/shift/no-go task. We found that individuals with SOT exhibited increased rsFC within the ECN compared with controls, while schizotypal individuals exhibited the opposite. Individuals with OCS exhibited decreased rsFC within the ECN and between the ECN and the default mode network (DMN), relative to controls. No significant correlational results between altered rsFC related to the ECN with executive function performance were found after corrections for multiple comparisons in three subclinical groups. Our findings showed that individuals with SOT had increased rsFC within the ECN, while schizotypal individuals and individuals with OCS showed the opposite. Our findings provide evidence for possible neural substrates of subclinical comorbidity of OCS and schizotypy.

Distinct clinical manifestations of obsessive-compulsive disorder are associated with cortical thickness alteration.

BACKGROUND: Although brain structural changes have been reported in patients with obsessive-compulsive disorder (OCD), results from previous studies have been inconsistent. A growing number of studies have focused on obsessive beliefs and impulsivity which could be involved in the occurrence and maintenance of OCD symptoms. The present study aimed to examine whether there are distinct brain structural changes in patients with different OCD subgroups. METHODS: Eighty-nine patients with OCD and 42 healthy controls were recruited to undergo structural magnetic resonance imaging brain scan. OCD patients were classified into subgroups according to scores of the Obsessive Belief Questionnaire (OBQ-44) and the Barratt Impulsiveness Scale (BIS-11) using cluster analysis. Group comparisons in cortical thickness and subcortical volumes between all OCD patients and healthy controls, as well as between subgroups of OCD patients and healthy controls, were carried out. RESULTS: OCD patients with more obsessive beliefs and attentional impulsivity (OCD_OB_AT) had reduced cortical thickness at the inferior parietal gyrus, the superior and middle temporal gyrus and the insula compared with OCD patients with higher score on the non-planning impulsivity (OCD_NP, corrected p < 0.05). The whole group of OCD patients and both subgroups showed reduced cortical thickness at the superior parietal gyrus compared with controls (uncorrected p < 0.01, number of vertices > 100). CONCLUSION: Our results suggest that apart from distinct phenomenology, there are distinct neural correlates of different OCD subgroups based on obsessive beliefs and impulsivity. These neural correlates may have clinical significance and should be considered in future research.

Network analysis of executive function, emotion, and social anhedonia.

This study constructed the network structure of social anhedonia, emotion processing, and executive function in college students using network analysis. We calculated the strength of each node in the network. The results suggest that social anhedonia had negative effects on executive function, emotion experience, and emotion expression.

Negative belief-updating bias for positive daily life events in individuals with schizophrenia and social anhedonia.

INTRODUCTION: Low-pleasure beliefs are found in both patients with schizophrenia (SZ) and individuals with high social anhedonia (SocAnh), and are associated with anhedonia. However, little is known about the development and maintenance of these low-pleasure beliefs in the clinical and subclinical populations. We investigated whether patients with SZ and individuals with high SocAnh have deficits in updating their beliefs, which may contribute to the understanding of the formation and maintenance of low-pleasure beliefs. METHODS: The Modified Belief Updating Task was administered to assess belief-updating patterns in a clinical sample (36 SZ patients and 30 matched controls) and a subclinical sample (27 individuals with high SocAnh and 30 matched controls). RESULTS: We found that compared with controls, SZ patients updated their beliefs to a greater extent and more frequently when receiving bad news for positive life events, but not for negative life events. Moreover, individuals with high SocAnh also exhibited similar patterns in updating their beliefs for positive life events after controlling depressive symptoms. CONCLUSIONS: Our findings suggest that negative belief-updating patterns for positive events may play an important role in the formation and maintenance of low-pleasure beliefs in patients with SZ and individuals with high SocAnh.

Schizotypal and obsessive-compulsive traits: Co-occurrence rate and relationship with executive function, emotion experience, and emotion expressivity in college students.

Empirical findings suggest that there is an overlap between schizophrenia and obsessive-compulsive disorder (OCD). These disorders also have a high comorbidity rate. However, little is known about the impact of co-occurring schizotypal and obsessive-compulsive traits on executive function, emotion experience, and emotion expressivity in the normal population. The present study examined the prevalence of coexisting schizotypal and obsessive-compulsive traits and the relationship between these two traits in a sample of healthy college students. We also conducted a moderation analysis to explore the effect of these two type of traits on executive function, emotion experience, and emotion expressivity. We recruited 3,319 participants to complete the Schizotypal Personality Questionnaire (SPQ) and the Obsessive-Compulsive Inventory - Revised (OCI-R). A subset of them (n = 575) also completed the Chinese versions of the Dysexecutive Questionnaire (DEX), the Temporal Experience of Pleasure Scale (TEPS), and the Emotional Expressivity Scale (EES). We found that the prevalence of co-occurring schizotypal and OCD traits was 3.33%. All the subscales of the SPQ and the OCI-R significantly correlated with each other. Both traits had a negative impact on executive function and emotion expressivity. The interaction between the disorganization dimension of schizotypal traits and OCD traits had a significant effect on executive function, but not emotion experience or emotion expressivity. This study was limited by its cross-sectional design and recruitment of only college students. These findings suggest that there is an approximately 3% rate of co-occurring schizotypal and obsessive-compulsive traits in a healthy college student sample. The interaction between these two types of traits may influence executive function.

Altered grey matter volume and white matter integrity in individuals with high schizo-obsessive traits, high schizotypal traits and obsessive-compulsive symptoms.

Altered brain structures have been found in patients with schizo-obsessive disorder, schizophrenia and obsessive-compulsive disorder in previous studies. However, it is unclear whether similar brain changes are also found in individuals with high schizo-obsessive traits (SOT), high schizotypal traits (SCT) and obsessive-compulsive symptoms (OCS). We examined grey matter volume (GMV) and white matter integrity (WMI, including fractional anisotropy, mean diffusivity, axial diffusivity and radial diffusivity) in 26 individuals with high SOT, 30 individuals with high SCT, 25 individuals with OCS and 30 individuals with low trait scores (LT) in this study. Correlation analysis between GMV, WMI, Schizotypal Personality Questionnaire (SPQ) scores and Obsessive-Compulsive Inventory-Revised (OCI-R) scores in the subclinical groups was also carried out. We found that the SOT group exhibited increased GMV at the right superior occipital gyrus and the left postcentral gyrus compared with the LT group. The SCT group exhibited increased GMV at the right precentral gyrus and the bilateral cuneus compared with the LT group, and decreased fractional anisotropy at the anterior corona radiata compared with the other three groups. The OCS group exhibited increased GMV at the left superior temporal gyrus and decreased GMV at the left pre-supplementary motor area compared with the LT group. These findings highlight specific brain changes in individuals with high SOT, high SCT and OCS, and may thus provide new insights into the neurobiological changes that occur in sub-clinical populations of these disorders.

Humour processing deficits in individuals with social anhedonia.

Humour processing comprises the humour comprehension and the humour appreciation phases. Patients with schizophrenia have impaired humour processing. However, it is unclear whether such deficits affect subclinical populations such as individuals with social anhedonia. Our study recruited forty-eight individuals with high levels of social anhedonia (HSA, screened by the Revised Chapman Social Anhedonia Scale) and 50 individuals with low levels of social anhedonia (LSA). Participants completed behavioural tasks which tapped into humour comprehension and appreciation, and a set of questionnaires assessing their sense of humour, humour styles and subjective experiential pleasure. Using signal detection theory analysis, the d' and ß values were generated to measure the detection of humour signal in the comprehension phase and the inner criteria of the humour appreciation respectively. The results showed that the HSA and LSA groups did not differ in humour signal detection (d') but the HSA group had significantly higher inner criteria of humour appreciation (ß) than the LSA group. The ß value was correlated with experiential anticipatory pleasure in all participants. The HSA group had significantly lower within-group coherence than the LSA group when processing humour. Our findings suggested that individuals with social anhedonia have impaired humour processing.