Guowei Wu

Distinctive patterns of functional connectivity (FC) abnormalities in neural circuitry has been reported in patients with bipolar depression (BD) and unipolar depression (UD). However, it is unclear that whether this distinct functional connectivity patterns are diagnosis specific between BD and UD. This study aimed to compare patterns of functional connectivity among BD, UD and healthy controls (HC) and determine the distinct functional connectivity patterns which can differentiate BD from UD. Totally 23 BD, 22 UD, and 24 HC were recruited to undergo resting-state fMRI scanning. FC between each pair of brain regions was calculated and compared among the three groups, the associations of FC with depressive symptom were also analyzed. Both patient groups showed significantly decreased cerebral-limbic FC located between the default mode network [posterior cingulated gyrus (PCG) and precuneus] and limbic regions (hippocampus, amygdala and thalamus) than HC. Moreover, the BD group exhibited more decreased FC mainly in the cortical regions (middle temporal gyrus, PCG, medial superior frontal gyrus, inferior occipital gyrus and superior temporal gyrus), but the UD group is more associated with limbic alterations. These decreased FCs were negatively correlated with HAMD scores in both BD and UD patients. BD and UD patients demonstrate different patterns of abnormal cerebral-limbic FC, reflected by decreased FC within cerebral cortex and limbic regions in BD and UD, respectively. The distinct FC abnormal pattern of the cerebral-limbic circuit might be applied as biomarkers to differentiate these two depressive patient groups.

Abnormal decision-making processes have been observed in patients with major depressive disorder (MDD). However, it is unresolved whether MDD patients show abnormalities in decision making in a social interaction context, in which decisions have actual influences on both the self-interests of the decision makers per se and those of their partners. Using a well-studied ultimatum game (UG), which is frequently used to investigate social interaction behavior, we examined whether MDD can be associated with abnormalities in social decision-making behavior by comparing the acceptance rates of MDD patients (N = 14) with those of normal controls (N = 19). The acceptance rates of the patients were lower than those of the normal controls. Additionally, unfair proposals were accepted at similar rates from computer partners and human partners in the MDD patients, unlike the acceptance rates in the normal controls, who were able to discriminatively treat unfair proposals from computer partners and human partners. Depressed patients show abnormal decision-making behavior in a social interaction context. Several possible explanations, such as increased sensitivity to fairness, negative emotional state and disturbed affective cognition, have been proposed to account for the abnormal social decision-making behavior in patients with MDD. This aberrant social decision-making behavior may provide a new perspective in the search to find biomarkers for the diagnosis and prognosis of MDD.

Background: Malingering detection has emerged as an important issue in clinical and forensic settings. The Structured Interview of Reported Symptoms-2 (SIRS-2) was designed to assess the feigned symptoms in both clinical and non-clinical subjects. The aim of the study was to examine the reliability and validity of the Chinese version of this scale. Methods: Two studies were conducted to evaluate the reliability and validity of the Chinese Version of SIRS-2. In Study one, with a simulation design, the subjects included a. 40 students asked to simulate symptoms of mental illness; b. 40 general psychiatric inpatients and c. 40 students asked to reply to questions honestly. Scales scores for feigning symptoms among three groups were carried out for discriminant validity of the Chinese Version of SIRS-2. Minnesota Multiphasic Personality Inventory-2(MMPI-2) was administered in 80 undergraduate students. In Study two, with a known-groups comparison design, scales scores for feigning symptoms were compared between 20 suspected malingerers and 80 psychiatric outpatients from two forensic centers using the Chinese Version of SIRS-2. Results: The Chinese Version of SIRS-2 demonstrated satisfactory internal consistency in both study one and two. In study one, criterion validity of this scale was supported by its significantly positive correlation with the MMPI-2 (r = 0.282 ~ 0.481 for Infrequency), and by its significantly negative correlation with the MMPI-2 (r = -0.255 ~ -0.519 for Lie and -0.205 ~ 0.391 for Correction). Scores of 10 out of 13 subscales of the Chinese Version of SIRS-2 for simulators were significantly higher than scores of honest students and general psychiatric patients. In study two, the mean scores of the Chinese Version of 13 subscales for suspected malingerers were significantly higher than those of psychiatric outpatients. For discriminant validity, it yielded a large effect size (d = 1.80) for the comparison of the participant groups in study one and two. Moreover, the sensitivity (proportion of malingerers accurately identified by the measure) and specificity (proportion of people accurately classified as responding honestly) of the Chinese version of SIRS-2 in the detection of malingering in these two studies are acceptable. Conclusions: The Chinese version of the SIRS-2 has good psychometric properties and is a valid and reliable tool for detection of malingering in Chinese populations.