Xuan Ouyang

Schizophrenic Patients and Their Unaffected Siblings Share Increased Resting-State Connectivity in the Task-Negative Network but Not Its Anticorrelated Task-Positive Network

BACKGROUNDnAbnormal connectivity of the anticorrelated intrinsic networks, the task-negative network (TNN), and the task-positive network (TPN) is implicated in schizophrenia. Comparisons between schizophrenic patients and their unaffected siblings enable further understanding of illness susceptibility and pathophysiology. We examined the resting-state connectivity differences in the intrinsic networks between schizophrenic patients, their unaffected siblings, and healthy controls.nnnMETHODSnResting-state functional magnetic resonance images were obtained from 25 individuals in each subject group. The posterior cingulate cortex/precuneus and right dorsolateral prefrontal cortex were used as seed regions to identify the TNN and TPN through functional connectivity analysis. Interregional connectivity strengths were analyzed using overlapped intrinsic networks composed of regions common to all subject groups.nnnRESULTSnSchizophrenic patients and their unaffected siblings showed increased connectivity in the TNN between the bilateral inferior temporal gyri. By contrast, schizophrenic patients alone demonstrated increased connectivity between the posterior cingulate cortex/precuneus and left inferior temporal gyrus and between the ventral medial prefrontal cortex and right lateral parietal cortex in the TNN. Schizophrenic patients exhibited increased connectivity between the left dorsolateral prefrontal cortex and right inferior frontal gyrus in the TPN relative to their unaffected siblings, though this trend only approached statistical significance in comparison to healthy controls.nnnCONCLUSIONnResting-state hyperconnectivity of the intrinsic networks may disrupt network coordination and thereby contribute to the pathophysiology of schizophrenia. Similar, though milder, hyperconnectivity of the TNN in unaffected siblings of schizophrenic patients may contribute to the identification of schizophrenia endophenotypes and ultimately to the determination of schizophrenia risk genes.

Frontal and cingulate gray matter volume reduction in heroin dependence: optimized voxel-based morphometry.

Aims:u2002 Repeated exposure to heroin, a typical opiate, causes neuronal adaptation and may result in anatomical changes in specific brain regions, particularly the frontal and limbic cortices. The volume changes of gray matter (GM) of these brain regions, however, have not been identified in heroin addiction.

Complementary diffusion tensor imaging study of the corpus callosum in patients with first-episode and chronic schizophrenia

BACKGROUNDnAbnormalities in the corpus callosum have long been implicated in schizophrenia. Previous diffusion tensor imaging (DTI) studies in patients with different durations of schizophrenia yielded inconsistent results. By comparing patients with different durations of schizophrenia, we investigated if white matter abnormalities of the corpus callosum emerge at an early stage in the illness or result from pathological progression.nnnMETHODSnWe recruited patients with first-episode schizophrenia, patients with chronic schizophrenia and age-, sex- and handedness-matched healthy controls. We used 2 DTI techniques (voxel-based and fibre-tracking DTI) to investigate differences in corpus callosum integrity among the 3 groups.nnnRESULTSnWith both DTI techniques, significantly decreased fractional anisotropy values were identified in the genu of corpus callosum in patients with chronic schizophrenia, but not first-episode schizophrenia, compared with healthy controls.nnnLIMITATIONSnThis study was cross-sectional, and the sample size was relatively small.nnnCONCLUSIONnAbnormalities in the genu of the corpus callosum might be a progressive process in schizophrenia, perhaps related to disease severity and prognosis.

Impaired interhemispheric connectivity in medication- naive patients with major depressive disorder

BACKGROUNDnAbnormalities in the anterior interhemispheric connections provided by the corpus callosum (CC) have long been implicated in major depressive disorder (MDD). The purpose of this study was to investigate interhemispheric connectivity in medication-naive patients with MDD by measuring fractional anisotropy in the CC with diffusion tensor imaging (DTI) techniques.nnnMETHODSnWe obtained DTI scans from medication-naive patients with MDD and from matched healthy controls. Fractional anisotropy values were compared using semiautomatic region of interest methods to localize the regional CC differences between these 2 groups.nnnRESULTSnWe enrolled 27 patients and 27 controls in our study. Fractional anisotropy values were significantly lower in the anterior genu of the CC in the MDD group than in the control group (p = 0.009, corrected); results were not significantly different in any other CC subregions.nnnLIMITATIONSnAs patients with MDD were already experiencing acute episodes, future studies of individuals at risk for MDD are warranted to elucidate the interhemispheric connectivity abnormalities associated with the predisposition to MDD.nnnCONCLUSIONnThe findings demonstrate abnormalities in the structural integrity of the anterior genu of the CC in medication-naive individuals with MDD, which may contribute to impairment of interhemispheric connectivity in patients with this disorder.

Morphological and functional abnormalities of salience network in the early-stage of paranoid schizophrenia

A salience network (SN), mainly composed of the anterior insula (AI) and anterior cingulate cortex (ACC), has been suggested to play an important role in salience attribution which has been proposed as central to the pathology of paranoid schizophrenia. The role of this SN in the pathophysiology of paranoid schizophrenia, however, still remains unclear. In the present study, voxel-based morphometry and resting-state functional connectivity analyses were combined to identify morphological and functional abnormalities in the proposed SN in the early-stage of paranoid schizophrenia (ESPS). Voxel-based morphometry and resting-state functional connectivity analyses were applied to 90 ESPS patients and 90 age- and sex-matched healthy controls (HC). Correlation analyses were performed to examine the relationships between various clinical variables and both gray matter morphology and functional connectivity within the SN in ESPS. Compared to the HC group, the ESPS group showed significantly reduced gray matter volume (GMV) in both bilateral AI and ACC. Moreover, significantly reduced functional connectivity within the SN sub-networks was identified in the ESPS group. These convergent morphological and functional deficits in SN were significantly associated with hallucinations. Additionally, illness duration correlated with reduced GMV in the left AI in ESPS. In conclusion, these findings provide convergent evidence for the morphological and functional abnormalities of the SN in ESPS. Moreover, the association of illness duration with the reduced GMV in the left AI suggests that the SN and the AI, in particular, may manifest progressive morphological changes that are especially important in the emergence of ESPS.

A comparative diffusion tensor imaging study of corpus callosum subregion integrity in bipolar disorder and schizophrenia

Structural magnetic resonance imaging (MRI) studies have provided evidence for corpus callosum (CC) white matter abnormalities in bipolar disorder (BD) and schizophrenia (SZ). These findings include alterations in shape, volume, white matter intensity and structural integrity compared to healthy control populations. Although CC alterations are implicated in both SZ and BD, no study of which we are aware has investigated callosal subregion differences between these two patient populations. We used diffusion tensor imaging (DTI) to assess CC integrity in patients with BD (n=16), SZ (n=19) and healthy controls (HC) (n=24). Fractional anisotropy (FA) of CC subregions was measured using region of interest (ROI) analysis and compared in the three groups. Significant group differences of FA values were revealed in five CC subregions, including the anterior genu, middle genu, posterior genu, posterior body and anterior splenium. FA values of the same subregions were significantly reduced in patients with SZ compared with HC. FA values were also significantly reduced in patients with BD compared to the HC group in the same subregions, excepting the middle genu. No significant difference was found between patient groups in any region. Most of the alterations in CC subregions were present in both the BD and SZ groups. These results imply an overlap in potential pathology, possibly relating to risk factors common to both disorders. The one region that differed between patient groups, the middle genu area, may serve as an illness marker and is perhaps involved in the different cognitive impairments observed in BD and SZ.

Distinct neurobehavioral consequences of prenatal exposure to sulpiride (SUL) and risperidone (RIS) in rats

Antipsychotic treatment during pregnancy is indicated when risk of drug exposure to the fetus is outweighed by the untreated psychosis in the mother. Although increased risk of congenital malformation has not been associated with most available antipsychotic drugs, there is a paucity of knowledge on the subtle neurodevelopmental and behavioral consequences of prenatal receptor blockade by these drugs. In the present study, antipsychotic drugs, sulpiride (SUL, a selective D2 receptor antagonist) and risperidone (RIS, a D2/5HT2 receptor antagonist) were administered to pregnant Sprague-Dawley dams from gestational day 6 to 18. Both RIS and SUL prenatal exposed rats had lower birth body weights compared to controls. RIS exposure had a significant main effect to retard body weight growth in male offspring until postnatal day (PND) 60. Importantly, water maze tests revealed that SUL prenatal exposure impaired visual cue response in visual task performance (stimulus-response, S-R memory), but not place response as reflected in hidden platform task (spatial memory acquisition and retention). In addition, prenatal SUL treatment reduced spontaneous activity as measured in open field. Both behavioral deficits suggest that SUL prenatal exposure may lead to subtle disruption of striatum development and related learning and motor systems. RIS exposure failed to elicit deficits in both water maze tasks and increased rearing in open field test. These results suggest prenatal exposure to SUL and RIS may produce lasting effects on growth, locomotion and memory in rat offspring. And the differences may exist in the effects of antipsychotic drugs which selectively block dopamine D2 receptors (SUL) as compared to second generation drugs (RIS) that potently antagonize serotonin and dopamine receptors.

Long- and short-term inpatients with schizophrenia in China: implications for community-based service development.

There is an increasing interest in the patterns of mental health care of people with serious mental illnesses in China, where outpatient and community‐based care are not fully developed and long‐term hospitalization is still not uncommon. Comparison of sociodemographic and clinical characteristics of long‐term and short‐term inpatients diagnosed with schizophrenia can be informative about pattern of treatment and their relationship to services needs.

The Psychiatry Major: A Curricular Innovation to Improve Undergraduate Psychiatry Education in China

ObjectiveIn China, a psychiatry major curriculum (PMC) has been implemented in select medical schools to improve the quality of undergraduate psychiatry education (UPE). Our aim was to describe this PMC and compare it with UPE in the standard Chinese clinical medicine curriculum (CMC). We also benchmarked PMC to UPE programs in the Hong Kong Special Administrative Region of China and the United States of America (USA) to determine how well it met standards of well-established programs and to highlight areas for improvement.MethodsBased on archival information, relevant literature, and communication with key informants, we described PMC and CMC in a Chinese school with both curriculums. We then compared PMC to UPE curriculums in Hong Kong and the USA.ResultsPMC provides substantially more comprehensive exposure to psychiatry than CMC, with more preclinical experiences and psychiatry clerkship course hours, greater diversity of clinical sites, and exploration of subspecialties. PMC employs a variety of teaching methods and offers mentoring for students. PMC has similar UPE preclinical content and course hours as programs in Hong Kong and the USA. PMC also provides more clinical exposure than programs in Hong Kong or the USA, although there is less variety in clinical settings.ConclusionWe recommend implementation of concrete measures to improve UPE in Chinese medical schools, using the PMC curriculum as a model that has been successfully implemented in China. We also recommend improvements to PMC based on comparisons with existing programs outside Mainland China.

Major depressive disorder in hemodialysis patients in China

Major depressive disorder (MDD) has been regarded as the most common psychiatric disorder among hemodialysis (HD) patients. However, few studies have investigated MDD in HD patients in Mainland China. This study sought to investigate the prevalence and treatment of MDD, as well as the sociodemographic and clinical characteristics in this population.