Comparison of trait and state mind wandering among schizotypal, subclinically depressed, and control individuals.

BACKGROUND: Mind wandering is a common phenomenon in daily life. However, the manifestations and cognitive correlates of mind wandering in different subclinical populations remain unclear. In this study, these aspects were examined in individuals with schizotypal traits and individuals with depressive symptoms, i.e., subclinical populations of patients with schizophrenia and depression. METHODS: Forty-two individuals with schizotypal traits, 42 individuals with subclinical depression, and 42 controls were recruited to complete a mind wandering thought sampling task (state level) and a mind wandering questionnaire (trait level). Measures of rumination and cognitive functions (attention, inhibition, and working memory) were also completed by participants. RESULTS: Both subclinical groups exhibited more state and trait mind wandering than did the control group. Furthermore, individuals with schizotypal traits demonstrated more trait mind wandering than individuals with subclinical depression. Rumination, sustained attention, and working memory were associated with mind wandering. In addition, mind wandering in individuals with subclinical depression can be accounted for by rumination or attention, while mind wandering in individuals with high schizotypal traits cannot be accounted for by rumination, attention, or working memory. CONCLUSIONS: The results suggest that individuals with high schizotypal traits and subclinical depression have different patterns of mind wandering and mechanisms. These findings have implications for understanding the unique profile of mind wandering in subclinical individuals.

Associations between intraindividual reaction time variability and prospective memory performance in patients with schizophrenia and healthy controls.

Introduction: Patients with schizophrenia exhibit prospective memory (PM) impairment. Intraindividual reaction time variability (IIRTV) is an index of attentional control that is required for PM. This study examined the differences in IIRTV between patients with schizophrenia and healthy controls and the relationship between IIRTV and PM performance.Method: Thirty-nine patients with schizophrenia and forty-two healthy controls were recruited to complete a PM task and the Sustained Attention to Response Task. IIRTV was calculated as the coefficient of variation (mean/SD) of reaction time over correctly responded trials in these tasks.Results: Patients with schizophrenia showed lower PM accuracy and increased IIRTV, while the associations between PM accuracy and IIRTV were significant in healthy controls but not in patients with schizophrenia.Conclusion: These findings suggest impaired PM and relationship between PM and attentional control in patients with schizophrenia.

Dissociation of Proactive and Reactive Cognitive Control in Individuals with Schizotypy: An Event-Related Potential Study.

OBJECTIVE: Patients with schizophrenia and individuals with schizotypy, a subclinical group at risk for schizophrenia, have been found to have impairments in cognitive control. The Dual Mechanisms of Cognitive Control (DMC) framework hypothesises that cognitive control can be divided into proactive and reactive control. However, it is unclear whether individuals with schizotypy have differential behavioural impairments and neural correlates underlying these two types of cognitive control. METHOD: Twenty-five individuals with schizotypy and 26 matched healthy controls (HCs) completed both reactive and proactive control tasks with electroencephalographic data recorded. The proportion of congruent and incongruent trials was manipulated in a classic colour-word Stroop task to induce proactive or reactive control. Proactive control was induced in a context with mostly incongruent (MI) trials and reactive control in a context with mostly congruent (MC) trials. Two event-related potential (ERP) components, medial frontal negativity (MFN, associated with conflict detection) and conflict sustained potential (conflict SP, associated with conflict resolution) were examined. RESULTS: There was no significant difference between the two groups in terms of behavioural results. In terms of ERP results, in the MC context, HC exhibited significantly larger MFN (360-530 ms) and conflict SP (600-1000 ms) amplitudes than individuals with schizotypy. The two groups did not show any significant difference in MFN or conflict SP in the MI context. CONCLUSIONS: The present findings provide initial evidence for dissociation of neural activation between proactive and reactive cognitive control in individuals with schizotypy. These findings help us understand cognitive control deficits in the schizophrenia spectrum.

Mind wandering in schizophrenia: A thought-sampling study.

Mind wandering has consistently been associated with impairments in cognition, emotion and daily performance. However, few experimental studies on mind wandering have been conducted in individuals with schizophrenia. The present study aimed to examine mind wandering in schizophrenia patients with a thought-sampling experiment embedded in a rapid go/no-go task and the relationship between the frequency of mind wandering and psychotic symptoms. Fifty-eight schizophrenia patients and 56 matched healthy controls were recruited and engaged in a task that assessed mind wandering. The results showed that schizophrenia patients (1.4%) reported less frequent mind wandering than healthy controls (5.8%). Moreover, there was no significant correlation between the frequency of mind wandering and psychotic symptoms in schizophrenia patients. Further studies in different stages of schizophrenia and in patients with more severe psychotic symptoms are needed to demonstrate a more comprehensive picture of mind wandering in schizophrenia.

The general facilitation effect of implementation intentions on prospective memory performance in patients with schizophrenia.

INTRODUCTION: Prospective memory (PM) refers to remembering to execute a planned intention in the future. It can be divided into event- and time-based, according to the nature of the PM cue. Event-based PM cues can be classified as focal or non-focal. Patients with schizophrenia (SCZ) have been found to be impaired in both event- and time-based PM. PM has been found to be improved by implementation intentions, which is an encoding strategy in the format of "if X then Y". This study examined the effect of implementation intentions on a non-focal event-based and a time-based PM task in patients with SCZ. METHODS: Forty-two patients with SCZ and 42 healthy controls were allocated to either an implementation intention or a control PM instruction condition and were asked to complete two PM tasks. RESULTS: Implementation intentions was found to improve performance in both the non-focal event-based and time-based PM tasks in patients with SCZ and healthy controls, with no costs to the ongoing task. The improvement in time-based PM performance in the implementation intentions condition was partially mediated by the frequency of clock checking behaviour. CONCLUSIONS: Implementation intentions can facilitate PM performance in patients with SCZ and has the potential to be used as a clinical intervention tool.

A Meta-Analysis of Working Memory Impairments in Autism Spectrum Disorders.

Autism spectrum disorders (ASD) are characterized by executive dysfunction, and working memory (WM) comprises one core component of executive function. Many studies have investigated WM impairments in individuals with ASD, however, a conclusive agreement has not been reached. The present study provided a meta-analytic review of WM impairments in individuals with ASD and evaluated potential moderating variables of this problem. Twenty-eight studies were included in this study, and the participants comprised 819 individuals with ASD and 875 healthy controls. A significant WM impairment (Cohen's d = -0.61) was identified in the individuals with ASD, however, this impairment was not associated with age. Results of moderation analyses showed that (a) spatial WM was more severely impaired than verbal WM and (b) the component of cognitive processing (maintenance vs. maintenance plus manipulation) did not affect the severity of WM impairments. These findings suggest that WM is impaired in individuals with ASD and may have implications for interventions related to WM impairments in these individuals.

The effect and mechanisms of implementation intentions on prospective memory in individuals with and without schizotypal personality features.

Prospective memory (PM) refers to remembering to do something at a future time. Studies have shown that implementation intention can improve PM performance. The present study aimed to examine the effect and mechanism of implementation intention on PM in individuals prone for schizotypal personality disorder (SPD proneness) in a laboratory condition. A total of 51 participants with SPD proneness and 51 controls were administered a PM task. They were further randomly assigned to an implementation intention condition and a typical instruction condition. All participants completed the PM task with low and high cognitive load conditions. The results showed that implementation intention improved PM performances in both SPD prone and control groups, indicating that implementation intention was an effective strategy for improving PM performance. However, the mechanisms were different for the two groups. For controls, implementation intention did not affect their cognitive resources allocation strategy. Participants with SPD proneness allocated significantly more cognitive resources to the PM task in the implementation intention condition.

The Future-oriented Repetitive Thought (FoRT) scale: Validation in Chinese samples and application in the schizophrenia spectrum.

BACKGROUND: Repetitive thoughts are usually associated with psychopathology. The Future-oriented Repetitive Thought (FoRT) Scale is a measure designed to capture frequency of repetitive thought about positive and negative future events. However, the validity of the scale in Chinese population and its application in the schizophrenia spectrum have not been examined. METHODS: The current study aimed to examine the psychometric properties of the Chinese version of the FoRT scale and to apply it to the schizophrenia spectrum. In Study 1, three samples (total N = 1875) of university students were recruited for exploratory factor analysis, confirmatory factor analysis, and validity test, respectively. In Study 2, we identified subsamples with high schizotypal traits (N = 89) and low schizotypal traits (N = 89), and recruited 36 inpatients with schizophrenia and 41 matched healthy controls. RESULTS: The three-factor (pessimistic repetitive future thinking, repetitive thinking about future goals, and positive indulging about the future) structure of the FoRT scale with one item deleted, fitted the Chinese samples. And the scale could distinguish patients with schizophrenia and individuals with high schizotypal traits from controls. CONCLUSION: These findings support that the Chinese version of the FoRT scale is a valid tool and provide evidence for the potential applications in the schizophrenia spectrum.

Relationship between theta/beta ratio and mind wandering in schizotypy.

Negative association was found between the frontal theta/beta ratio and mind wandering in participants with high schizotypal traits, while no such association was found in participants with low schizotypal traits. These findings provide insights into the neural mechanism of mind wandering in individuals with high schizotypal traits.

A Meta-analysis of Mental Time Travel in Individuals with Autism Spectrum Disorders.

Autism spectrum disorders (ASD) are associated with cognitive dysfunctions, including mental time travel (MTT). However, findings on diminished MTT ability may be confounded by a number of factors, including the individuals' language ability, factors related to the MTT task and the demographic factors of participants. The present study provided a meta-analysis of MTT ability in people with ASD. The results showed significant overall reductions in MTT ability in people with ASD. Moderator analyses revealed that the variables examined did not explain the reduction in MTT ability. These findings suggest that MTT ability is diminished in people with ASD and that the degree of this diminishment may not depend on the characteristics of measures or demographic variables of people with ASD.

Neural correlates of schizotypal traits: Findings from connectome-based predictive modelling.

Schizotypal traits can be conceptualized as a phenotype for schizophrenia spectrum disorders. As such, a better understanding of schizotypal traits could potentially improve early identification and treatment of schizophrenia. We used connectome-based predictive modelling (CPM) based on whole-brain resting-state functional connectivity to predict schizotypal traits in 82 healthy participants. Results showed that only the negative network could reliably predict an individual's schizotypal traits (r = 0.29). The 10 nodes with the highest edges in the negative network were those known to play a key role in sensation and perception, cognitive control as well as motor control. Our findings suggest that CPM might be a promising approach to improve early identification and prevention of schizophrenia from a spectrum perspective.

Proactive and reactive response inhibition of individuals with high schizotypy viewing different facial expressions: An ERP study using an emotional stop-signal task.

The present study aimed to examine whether impairments in reactive (outright stopping) and proactive (preparation for stopping) response inhibition are affected by negative emotions in individuals with high schizotypy, a subclinical group at risk for schizophrenia, as well as the neural mechanisms underlying these processes. Twenty-seven participants with high schizotypy and 28 matched low-schizotypy individuals completed an emotional stop-signal task in which they responded to facial emotions (neutral or angry) or inhibited their responses (when the frame of the picture turned red). Electroencephalogram (EEG) data were also recorded during the task. At the neural level, analysis of go trials revealed that viewing angry faces impaired proactive inhibition. In addition, the high-schizotypy group exhibited a greater P3 amplitude in go trials in the neutral condition than the low-schizotypy group; however, no group difference was found in the angry condition. For stop trials (reactive inhibition), a smaller P3 amplitude was found in the angry condition than in the neutral condition. Moreover, high-schizotypy individuals showed smaller P3 amplitudes than low-schizotypy individuals. The current findings suggest that, at the neural level, viewing negative emotions impaired both proactive and reactive response inhibition. Individuals with high schizotypy exhibited impairments in proactive response inhibition in the neutral condition but not in the angry condition; they exhibited impaired reactive response inhibition in both emotion conditions. The present findings deepen our understanding of emotional response inhibition in individuals on the schizophrenia spectrum.

Proactive and reactive cognitive control for emotional conflict in individuals with high schizotypy: An ERP study.

OBJECTIVE: The present study aimed to examine how individuals with high schizotypy, a high risk group of schizophrenia patients, resolve emotional conflict in proactive and reactive control and the underlying neural mechanisms. METHODS: Thirty-two individuals with high schizotypy and 30 matched individuals with low schizotypy completed an emotional face-word Stroop task with electroencephalographic data recorded. The proportion of incongruent trials was manipulated in the task to induce proactive control (mostly incongruent trials context, MI context) or reactive control (mostly congruent trials context, MC context). Two event-related potential (ERP) components (N170 and N2) were examined, which represent face processing and cognitive control processes, respectively. RESULTS: In the MC context, significantly decreased N2 and N170 amplitudes were found in high schizotypy individuals compared with low schizotypy individuals, suggesting abnormal neural activity of reactive control in high schizotypy individuals. No significant differences were found between the two groups in the MI context. CONCLUSIONS: These results provide initial evidence for dissociation of neural activity of proactive and reactive control on emotional conflict in individuals with high schizotypy. SIGNIFICANCE: The current findings provide important insight into the emotional conflict resolution in the schizophrenia spectrum.

Preparation facilitates response inhibition based on a stop-signal task.

This study demonstrated that the higher stop-signal probability condition showed a longer go reaction time and shorter stop-signal reaction time (SSRT) compared with the lower stop-signal probability condition. In addition, preparation cost was correlated with SSRT. These results suggest that preparation facilitates response inhibition.

Neural correlates of mental time travel in individuals with high level of schizotypy.

BACKGROUND: Mental time travel (MTT) is the ability to re-experience past events (autobiographic memory, AM) and pre-experience possible future events (episodic future thinking, EFT) through mental simulation. Empirical findings suggest that individuals with high level of schizotypy exhibit MTT impairment. However, the neural correlates of this impairment remain unclear. METHOD: Thirty-eight individuals with high level of schizotypy and 35 low level of schizotypy were recruited to complete an MTT imaging paradigm. Participants were required to recall past events (AM condition), imagine possible future events (EFT condition) related to cue words, or generate exemplars related to category words (control condition) while undergoing functional Magnetic Resonance Imaging (fMRI). RESULTS: AM showed greater activation in precuneus, bilateral posterior cingulate cortex, thalamus, and middle frontal gyrus than EFT. Individuals with high level of schizotypy exhibited reduced activation in the left anterior cingulate cortex during AM (vs. Control) and in the medial frontal gyrus during EFT (vs. Control) compared to individuals with low level of schizotypy. Although psychophysiological interaction analyses did not show any significant group difference, individuals with high level of schizotypy exhibited functional connectivity between left anterior cingulate cortex (seed) and right thalamus, between medial frontal gyrus (seed) and left cerebellum during MTT, whereas individuals with low level of schizotypy did not exhibit these functional connectivities. CONCLUSION: These findings suggest that decreased brain activations may underlie MTT deficits in individuals with high level of schizotypy.

Mental time travel for self and others in individuals with a high level of schizotypy.

Mental time travel (MTT) is the ability to project oneself to the past or future through mental simulation. Moreover, MTT can involve self-related or other-related information. This study aimed to compare MTT in individuals with high levels of schizotypy and that in their counterparts with low levels of schizotypy. Participants with high (n = 37) and low (n = 37) levels of schizotypy completed an MTT task with four conditions [2 (Condition: self vs. other) × 2 (Time orientation: past vs. future)]. They were required to recall past events that had happened to themselves or to a non-intimate person, and to imagine possible future events that might happen to themselves or to a non-intimate person, related to cue words. Outcome measures included specificity, vividness, sense of experience, emotional valence, emotional intensity, proportion of first-person visual perspective in events, and difficulty in event generation. A 2 (Group: high vs. low levels of schizotypy) × 2 (Condition) × 2 (Time orientation) mixed analysis of variance was conducted on each index. Results showed that self-related MTT was more specific than other-related MTT in low levels of schizotypy participants but not in high levels of schizotypy participants. Participants with a high level of schizotypy reported fewer specific events, and reported events with lower vividness and positive emotion than did those with a low level of schizotypy. Self-related MTT showed higher levels of phenomenological characteristics than did other-related MTT. In conclusion, individuals with a high level of schizotypy have altered MTT, and cannot benefit from the self-advantage effect on the specificity of MTT.

The neural substrates of sex differences in balanced time perspective: A unique role for the precuneus.

Sex differences in various aspects of behaviour and cognition have been widely observed. Few studies, however, have explored potential sex differences in maintaining a balanced time perspective or their underlying neural correlates. To address these questions, two studies were conducted. In Study 1, time perspective was assessed in 1913 college students (796 males and 1117 females), revealing that females had a significantly more balanced time perspective relative to males. In Study 2, 58 males and 47 females underwent an assessment of time perspective and structural brain imaging. Voxel-based morphometry analysis and cortical thickness analysis were conducted to explore associations between the structural imaging data and balanced time perspective. Compared with males, females demonstrated a more balanced time perspective in the context of lower grey matter volume in the bilateral precuneus, right cerebellum, right putamen and left supplementary motor area. Analysis of cortical thickness failed to reveal any significant sex differences. Furthermore, lower grey matter volume of bilateral precuneus was associated with more balanced time perspective among all participants. Our findings point to a critical role for the precuneus in modulating a balanced time perspective, and extend our understanding of sex differences in human cognition. Future studies are required to determine whether sex differences in balanced time perspective are predictive of functional outcomes in daily life.

The relationship between schizotypal traits and satisfaction with life among Chinese young adults: The mediating effect of trait anxiety and mind wandering.

Schizotypal traits have been found to be negatively associated with satisfaction with life but the underlying mechanisms are not well understood. This study investigated the association between schizotypal traits and satisfaction with life and explored the mediating role of trait anxiety and mind wandering in the relationship between those two variables in a sample of Chinese young adults. One hundred and two individuals with high schizotypal traits and 104 individuals with low schizotypal traits were screened using the Schizotypal Personality Questionnaire. They completed a series of questionnaires including the Satisfaction with Life Scale, Trait Anxiety Inventory, and Mind Wandering Questionnaire. Results showed that: First, the high schizotypal trait group showed lower satisfaction with life, and higher trait anxiety and mind wandering frequency than the low schizotypal trait group. Second, the high schizotypal trait group, trait anxiety, and mind wandering negatively predicted satisfaction with life. Third, mediation analyses showed that all indirect effect paths in the mediation model were significant, that is, trait anxiety and mind wandering alone and together mediated the relationship between schizotypal trait group and satisfaction with life. In conclusion, high schizotypal trait is a risk factor for low satisfaction with life. The association between schizotypal traits and satisfaction with life was mediated by the combination of trait anxiety and mind wandering. This study has implications for improving life satisfaction in individuals with high schizotypal traits.

Prospective memory performance and its improvement in individuals with high schizotypal traits: Evidence from eye-tracking studies.

OBJECTIVE: This study aimed to examine prospective memory (PM) performance and the potential effect of implementation intention on PM performance and the underlying mechanisms in individuals with high schizotypyal traits (HSTs) using eye-tracking paradigms. METHODS: In Experiment 1, 30 individuals with HSTs and 30 individuals with low schizotypal traits (LSTs) underwent a visual search task that involved PM cues, and participants' eye movements were recorded. In Experiment 2, 50 individuals with HSTs were randomly assigned to the implementation intention group and typical instruction group. RESULTS: In Experiment 1, individuals with HSTs had a lower PM accuracy and performed less PM cue monitoring (indicated by fewer total fixation counts on distractor words) than individuals with LSTs. In Experiment 2, implementation intention significantly improved PM accuracy and increased total fixation counts on distractor words in individuals with HSTs compared to the HST group with typical instruction. CONCLUSIONS: Individuals with HSTs were impaired in PM and showed reduced cue monitoring compared to individuals with LSTs. Implementation intention improved PM performance and facilitated cue monitoring in individuals with HSTs. SIGNIFICANCE: Our findings indicate that cue monitoring may be an important process of intervention target for PM for individuals in the schizophrenia spectrum.

A meta-analysis of the effects of episodic future thinking on delay discounting.

Delay discounting (DD) refers to the phenomenon in which the subjective value of future rewards is reduced over time. There are individual differences in the DD rate, and increased discounting has been observed in those with various psychiatric disorders. Episodic future thinking (EFT) is the act of vividly imagining events that may happen in the future. Studies have shown that EFT could reduce DD, although inconsistent results have been reported. The aim of this meta-analysis was to clarify the efficacy with which EFT reduces DD and to identify potential moderators. Forty-seven studies (including 63 contrasts) were included in the final analysis. EFT was found to significantly reduce DD (Hedges' g = 0.52). Moderator analysis showed that positive EFT (g = 0.64) was more effective in reducing DD than EFT with the valence not specifically mentioned (g = 0.28) and EFT with neutral or negative valence (g = -0.03). In addition, several factors related to the control task and DD task were related to the efficacy of EFT to reduce DD. These findings have implications for using EFT to reduce DD in the future.