ABSTRACT
Background: Individuals with major depressive disorder have a cognitive bias toward emotional stimuli, which influences the quality and speed of emotional information processing. This study aimed to understand the factors underlying this bias by identifying when it occurs during information processing using an information processing model. Methods: A total of 57 participants-19 each [ (16 (84.21%) females and 3 (15.79%) males per group)], for the first-episode MDD (FMDD), recurrent episodes MDD (RMDD), and healthy controls (HCs) - matched for sex and hand preference, completed event-related potentials (ERP) to perform psychological function and a choice response time task. Results: Results revealed that recurrent episodes major depressive disorder participants had decreased N2b and P3b amplitudes but increased contingent negative variation during the processing of happy and neutral facial stimuli, relative to their counterparts. Both recurrent episodes major depressive disorder and first-episode major depressive disorder participants used a parallel information processing strategy for happy information at P3a latency, while healthy controls used a linear information processing strategy. Conclusion: The use of a parallel processing strategy among individuals with major depressive disorder may have led to impaired "happy" information processes, possibly explaining why individuals with major depressive disorder are less efficient than healthy controls. The results suggest the possibility that biases related to the processing of "happy" information among individuals with major depressive disorder may be related to a tendency for these individuals to engage in superficial decision-making. Future research is needed to examine the processes contributing to people with major depressive disorder having challenges with inhibition-facilitation of emotional stimuli.
ABSTRACT
BACKGROUND: Schizophrenia is known for their theory of mind (ToM) impairment. However, this impairment in schizotypy (schizotypal traits) lacks investigation. AIMS: The present study investigated: (1) whether ToM ability was impaired in schizotypy; (2) whether the ERP amplitudes in nine brain regions of interest associated with ToM (e.g., frontal region) in schizotypy and healthy controls differed; and (3) whether the relationship between ToM performances and ERP amplitudes in schizotypy differed from that in healthy controls. METHOD: Forty eight adolescents and young adults (16 schizotypy) with the mean age of 18 years were tested. The Reading the Mind in the Eyes Test (RMET) was used to assess their ToM during which ERP amplitudes were recorded. RESULTS: The schizotypy group showed significantly lower ERP amplitudes in all conditions of RMET in frontal, frontal-central, central, occipital and temporal regions when compared to those in healthy controls. Also, schizotypy's ERP amplitudes in the frontal, frontal-central, central, occipital, and temporal regions were different from those in the healthy individuals in responding to different types of ToM stimuli (positive, negative and neutral). In schizotypy group, reaction time responding to emotional stimuli was negatively related to ERP amplitudes in the frontal, central-parietal, parietal, occipital, and occipito-temporal regions during RMET while no significant correlations were found in healthy controls. CONCLUSION: The present findings inform us with the knowledge regarding the neural and behavioral abnormality of ToM in schizotypy, suggesting that brain activity can be an alternative to detect ToM impairment in schizotypy.
ABSTRACT
The adverse effects of depression on patients' life have been reported but information about its effects on the sequential organization of the information processing stages remains poorly understood as previous studies focused only on distinct stages. This study adds to existing knowledge by examining the effect of major depressive disorder (MDD) on the sequential organization of information processing, executive and community functioning. Fifty-seven participants with 19 participants each for first episode depression (FMDD), recurrent episodes depression (RMDD), and healthy controls (HCs) participated in this study. They completed assessments on executive and community functioning measures, and choice reaction time task (CRTT) for the event-related potential (ERP) data. Findings revealed no significant between-group difference in executive functioning but participants with depression (FMDD and RMDD) were found to be more depressed, with FMDD participants having worse community functioning skills compared with HCs. There was no significant between-group main effect on behavioral data. ERP data showed significantly less positive-going P3b among RMDD participants compared with HCs. FMDD participants used a different information processing strategy at P1, while HCs and RMDD participants used a different processing strategy at N2b compared with the other group(s), respectively. The results suggest the use of multifaceted assessment to get a holistic view of the health status of people with MDD in order to inform clinicians on the appropriate interventional strategies needed for the patient.
