Schizophrenia: measurements of psychopathology

Serum S100B protein and white matter changes in schizophrenia before and after medication

Schizophrenia patients have abnormalities in white matter (WM) integrity in brain regions. S100B has been shown to be a marker protein for glial cells. The atypical antipsychotics have neuroprotective effects on the brain. It is not clear whether antipsychotics can induce S100B changes and improve symptoms by protecting oligodendrocytes. To investigate WM and S100B changes and associations and determine the effect of quetiapine on WM and S100B in schizophrenia patients, we determined serum S100B levels with solid phase immunochromatography and fractional anisotropy（FA）values of 36 patients and 40 healthy controls. Patients exhibited significantly higher serum concentrations of S100B and decreased FA values in left postcentral，right superior frontal，right thalamus, and left inferior occipital gyrus, while higher in right temporal cortex WM compared with healthy controls. Following treatment with quetiapine, patients had decreased S100B and higher FA values in right cerebellum，right superior frontal，right thalamus, and left parietal cortex，and decreased FA values in right temporal cortex WM compared with pre-treatment values. Furthermore, S100B were negatively correlated with PANSS positive scores and positively correlated with FA values in the left postcentral cortex. In addition，the percentage change in FA values in the right temporal cortex was positively correlated with the percentage change in the S100B, percentage reduction in PANSS scores, and percentage reduction in PANSS-positive scores. Our findings demonstrated abnormalities in S100B and WM microstructure in patients with schizophrenia. These abnormalities may be partly reversed by quetiapine treatment.

Associations of Systemic Inflammation and Senescent Cell Biomarkers with Clinical Outcomes in Older Adults with Schizophrenia

Individuals with schizophrenia suffer from higher morbidity and mortality throughout life partly due to acceleration of aging-related diseases and conditions. Systemic inflammation is a hallmark of aging and is also observed in schizophrenia. An improved understanding of how inflammation and accelerated aging contribute to long-term health outcomes in schizophrenia could provide more effective treatments to preserve long-term cognitive and physical function. In this pilot cross-sectional study, 24 older adults (≥55 years old) with schizophrenia were assessed on symptoms (Positive and Negative Syndrome Scale), neurocognition (Matrics Consensus Cognitive Battery), mobility (Timed Get Up and Go), and general health (SF-12). Serum levels of 112 different cytokines were measured, from which we derived estimated senescence-associated secretory phenotype (SASP) scores for each participant. Two-tailed Pearson's bivariate correlations were computed to test the associations between schizophrenia clinical outcomes with individual cytokines, and SASP. Higher levels of eotaxin, IL-1α, IL-1β, and IFNα are associated with both worse PANSS negative and depressive symptoms scores. IL-1α and IL-1β negatively associated with general physical health whereas eotaxin negatively associated with mobility and global cognition. Overall, we found that specific inflammatory cytokines, but not composite measurements of SASP, are associated with clinical outcomes in older adults with schizophrenia.

Proverb comprehension in schizophrenia: A comprehensive review and meta-analysis.2

BACKGROUND

Examination of proverb comprehension has a long tradition in clinical diagnostics of individuals with schizophrenia (iSCZ). Deficits in the comprehension are considered common. Interpretations of proverbs are traditionally measured by their degree of abstraction and concreteness ('literalness'), but iSCZ's responses may also be illogical or 'bizarre'. Experimental research on proverb comprehension starts in the 1940s. Since then, the specificity of proverb tests has often been questioned, but has never been the subject of a meta-analysis. The aim of this meta-analysis is to include all experimental research, including historical studies, that meets quality criteria and compares the responses to proverbs in iSCZ with those in healthy controls (HC) or clinical controls (CC).

METHODS

PubMed, Web of Science, and PsycInfo databases were searched. After coding 121 articles, 27 (median publication year 1982) were included and multi-level meta-analyses performed. Moderator analyses were performed on response format (multiple-choice vs. verbal responses), proverb test, scoring method, language, acute vs. chronic stage of iSCZ, time of publication, clinical vs. healthy control group, age, IQ/education, and gender. Publication bias was assessed using funnel plots, trim and fill method and Egger's test.

RESULTS

The search identified 27 eligible studies for inclusion. Studies were published between 1956 and 2020 and predominantly older than 30 years (median: 1982). The Gorham Proverbs Test was the most established test and predominantly conducted in English. CC mostly consisted of depressive disorders. Pooled estimates yielded statistically significant less abstract (g = -1.00; 95%CI, -1.34 to -1.67), more concrete (g = 0.69; 95%CI, 0.35-1.03), and more bizarre (g = 1.08; 95%CI, 0.74-1.41) responses in iSCZ compared to controls. The type of control group moderated all three effects, with greater differences of iSCZ compared to HC than to CC in abstraction and bizarreness, and no significant group difference between iSCZ and CC in concreteness. Meta-regressions indicated IQ/education and age as possible sources of variability in abstraction and bizarreness.

CONCLUSIONS

While lower abstraction and higher bizarreness seems a characteristic of iSCZ, the diagnostic specificity of a concrete response was astonishingly low. The lack of a unified definition for concretism and limited consideration of cultural diversity contributed to these complex findings. Future research should focus on exploring the qualitative aspects of proverb comprehension and the association between symptomatology types and misinterpretations to improve diagnostic accuracy.

Shortened Positive and Negative Symptom Scale as an Alternate Clinical Endpoint for Acute Schizophrenia Trials: Analysis from the US Food & Drug Administration

Objective

To evaluate the performance of the individual Positive and Negative Symptom Scale (PANSS) items, and to assess the feasibility of using a shortened version of the PANSS as an alternative regulatory endpoint for evaluating the efficacy of drugs to treat schizophrenia.

Design

Data from 32 randomized, placebo‐controlled, multiregional trials from eight atypical antipsychotic programs (N=14,219) submitted to the US Food and Drug Administration were used in the analyses. Item response theory analysis on baseline PANSS item scores was used to identify the best performing items of the PANSS to derive the shortened, or modified, PANSS (mPANSS). Concordance rates of mPANSS total with the PANSS total trial results at week 6 were examined, and implications of using mPANSS on trial sample size evaluated.

Results

Five of the positive items, six of the negative items, and eight of the general items were assessed as sensitive to describe the underlying symptom severity and comprise mPANSS. The overall concordance rate between mPANSS and total PANSS results at week 6 was 97.6%. Using mPANSS resulted in a 32% reduction in samples size relative to using total PANSS.

Conclusions

Based on this research, mPANSS may be considered a potential alternative clinical endpoint for acute schizophrenia trials. However, it will need psychometric validation before it can be fully implemented in clinical trials in place of total PANSS. If such implementation occurs, the development of new drugs for schizophrenia, a public health imperative, may be considerably improved.

The current research is a comprehensive analysis of one of the largest database of randomized, placebo‐controlled trials for drugs indicated for schizophrenia to evaluate the feasibility of a shortened version of PANSS (mPANSS) as a regulatory clinical endpoint.

The mPANSS consisting of 19 out of 30 PANSS items was identified to be sensitive to assess the schizophrenia symptom severity by item response analysis.

Based on this research, mPANSS may be considered a potential alternative clinical endpoint for acute schizophrenia trials.

Two Thalamic Regions Screened Using Laser Capture Microdissection with Whole Human Genome Microarray in Schizophrenia Postmortem Samples

We used whole human genome microarray screening of highly enriched neuronal populations from two thalamic regions in postmortem samples from subjects with schizophrenia and controls to identify brain region-specific gene expression changes and possible transcriptional targets. The thalamic anterior nucleus is reciprocally connected to anterior cingulate, a schizophrenia-affected cortical region, and is also thought to be schizophrenia affected; the other thalamic region is not. Using two regions in the same subject to identify disease-relevant gene expression differences was novel and reduced intersubject heterogeneity of findings. We found gene expression differences related to miRNA-137 and other SZ-associated microRNAs, ELAVL1, BDNF, DISC-1, MECP2 and YWHAG associated findings, synapses, and receptors. Manual curation of our data may support transcription repression.

Serum BDNF Is Positively Associated With Negative Symptoms in Older Adults With Schizophrenia

OBJECTIVES

Older adults with chronic schizophrenia are at greater risk for functional disability and poorer health outcomes than those without serious mental illness. These individuals comprise 1-2% of the elderly population in the United States and are projected to number approximately 15 million by 2030. The symptoms of schizophrenia can be disabling for individuals, significantly reducing quality of life. Often, the negative symptoms (NS) are the most resistant to treatment and are considered a marker of illness severity, though they are challenging to measure objectively. Biomarkers can serve as objective indicators of health status. Brain-derived neurotrophic factor (BDNF) is a potential biomarker for schizophrenia and may serve as an important indicator of illness severity.

METHODS

A cross-sectional study with 30 older adults with chronic schizophrenia. Participants were assessed on serum levels of BDNF and psychiatric symptoms (Positive and Negative Syndrome Scale). Pearson's bivariate correlations (two-tailed) and linear regression models were used.

RESULTS

A significant positive association ( p < .05) was found between higher serum levels of BDNF and greater severity for the NS items of passive, apathetic, social withdrawal, and emotional withdrawal. In multivariate analyses, the association remained significant.

CONCLUSIONS

Although the association between BDNF and NS was not in the expected direction, the data corroborate findings from previous work in patients with schizophrenia. It is possible that higher serum levels of BDNF reflect compensatory neuronal mechanisms resulting from neurodevelopmental dysfunction.

Altered Coupling Between Resting-State Cerebral Blood Flow and Functional Connectivity in Schizophrenia

BACKGROUND

Respective changes in resting-state cerebral blood flow (CBF) and functional connectivity in schizophrenia have been reported. However, their coupling alterations in schizophrenia remain largely unknown.

METHODS

89 schizophrenia patients and 90 sex- and age-matched healthy controls underwent resting-state functional MRI to calculate functional connectivity strength (FCS) and arterial spin labeling imaging to compute CBF. The CBF-FCS coupling of the whole gray matter and the CBF/FCS ratio (the amount of blood supply per unit of connectivity strength) of each voxel were compared between the 2 groups.

RESULTS

Whole gray matter CBF-FCS coupling was decreased in schizophrenia patients relative to healthy controls. In schizophrenia patients, the decreased CBF/FCS ratio was predominantly located in cognitive- and emotional-related brain regions, including the dorsolateral prefrontal cortex, insula, hippocampus and thalamus, whereas an increased CBF/FCS ratio was mainly identified in the sensorimotor regions, including the putamen, and sensorimotor, mid-cingulate and visual cortices.

CONCLUSION

These findings suggest that the neurovascular decoupling in the brain may be a possible neuropathological mechanism of schizophrenia.

Association between schizophrenia symptoms and neurocognition on mobility in older adults with schizophrenia

OBJECTIVES

Older persons with schizophrenia develop problems associated with aging, such as poor mobility, at more rapid rates than people without serious mental illness. Decrements in mobility contribute to poor health outcomes. Impaired neurocognitive function and psychiatric symptoms are central aspects of schizophrenia. The purpose of this study was to determine the association between neurocognitive impairment and schizophrenia symptoms to mobility in older adults with schizophrenia.

METHODS

A cross-sectional study with 46 older adults with schizophrenia. Participants were assessed on neurocognitive function (MATRICS Consensus Cognitive Battery), psychiatric symptoms (Positive and Negative Syndrome Scale or PANSS), and mobility (Timed Get Up and Go or TGUG test). Pearson's bivariate correlations (two-tailed) and a simultaneous regression model were used.

RESULTS

Lower severity of negative symptoms and faster speed of processing tests were associated with faster TGUG time in bivariate correlations and multivariate regression analyses (p < .05).

CONCLUSION

Our data suggest that lower negative symptoms and faster speed of processing positively impact mobility in older patients with schizophrenia. Mobility interventions for this population need to target neurocognitive impairment and schizophrenia symptoms for optimal results.

Instruments for measuring mental health recovery: a systematic review

Persons in recovery, providers, and policymakers alike are advocating for recovery-oriented mental health care, with the promotion of recovery becoming a prominent feature of mental health policy in the United States and internationally. One step toward creating a recovery-oriented system of care is to use recovery-oriented outcome measures. Numerous instruments have been developed to assess progress towards mental health recovery. This review identifies instruments of mental health recovery and evaluates the appropriateness of their use including their psychometric properties, ease of administration, and service-user involvement in their development. A literature search using the Medline and Psych-INFO databases was conducted, identifying 21 instruments for potential inclusion in this review, of which thirteen met inclusion criteria. Results suggest only three instruments (25%) have had their psychometric properties assessed in three or more unique samples of participants. Ease of administration varied between instruments, and for the majority of instruments, development included service user involvement. This review updates and expands previous reviews of instruments to assess mental health recovery. As mental health care continues to transform to a recovery-oriented model of service delivery, this review may facilitate selection of appropriate assessments of mental health recovery for systems to use in evaluating and improving the care they provide.

Associations of schizophrenia symptoms and neurocognition with physical activity in older adults with schizophrenia

BACKGROUND

Low levels of physical activity contribute to the generally poor physical health of older adults with schizophrenia. The associations linking schizophrenia symptoms, neurocognition, and physical activity are not known. Research is needed to identify the reasons for this population's lack of adequate physical activity before appropriate interventions can be designed and tested.

DESIGN AND METHODS

In this cross-sectional study, 30 adults aged ≥55 years with schizophrenia were assessed on symptoms (Positive and Negative Syndrome Scale), neurocognition (MATRICS Consensus Cognitive Battery), and physical activity (Sensewear ProArmband). Pearson's bivariate correlations (two-tailed) and univariate linear regression models were used to test the following hypotheses: (1) more severe schizophrenia symptoms are associated with lower levels of physical activity and (2) more severe neurocognitive deficits are associated with lower levels of physical activity.

RESULTS

Higher scores on a speed-of-processing test were associated with more average daily steps (p = .002) and more average daily minutes of moderate physical activity (p = .009). Higher scores on a verbal working memory task were associated with more average daily minutes of moderate physical activity (p = .05). More severe depressive symptoms were associated with more average daily minutes of sedentary activity (p = .03).

CONCLUSION

Physical activity interventions for this population are imperative. In order for a physical activity intervention to be successful, it must include components to enhance cognition and diminish psychiatric symptoms.

The loudness dependence of auditory evoked potentials (LDAEP) as an indicator of serotonergic dysfunction in patients with predominant schizophrenic negative symptoms

Besides the influence of dopaminergic neurotransmission on negative symptoms in schizophrenia, there is evidence that alterations of serotonin (5-HT) system functioning also play a crucial role in the pathophysiology of these disabling symptoms. From post mortem and genetic studies on patients with negative symptoms a 5-HT dysfunction is documented. In addition atypical neuroleptics and some antidepressants improve negative symptoms via serotonergic action. So far no research has been done to directly clarify the association between the serotonergic functioning and the extent of negative symptoms. Therefore, we examined the status of brain 5-HT level in negative symptoms in schizophrenia by means of the loudness dependence of auditory evoked potentials (LDAEP). The LDAEP provides a well established and non-invasive in vivo marker of the central 5-HT activity. We investigated 13 patients with schizophrenia with predominant negative symptoms treated with atypical neuroleptics and 13 healthy age and gender matched controls with a 32-channel EEG. The LDAEP of the N1/P2 component was evaluated by dipole source analysis and single electrode estimation at Cz. Psychopathological parameters, nicotine use and medication were assessed to control for additional influencing factors. Schizophrenic patients showed significantly higher LDAEP in both hemispheres than controls. Furthermore, the LDAEP in the right hemisphere in patients was related to higher scores in scales assessing negative symptoms. A relationship with positive symptoms was not found. These data might suggest a diminished central serotonergic neurotransmission in patients with predominant negative symptoms.

Factor structure of the targeted inventory on problems in schizophrenia

Objective

The aim of this study was to explore the factor structure of a novel, 10-item rating scale, the Targeted Inventory on Problems in Schizophrenia (TIP-Sz). Determining the factor structure will be useful in the brief evaluation of medication and non-medication treatment of the disease.

Methods

An exploratory factor analysis was performed on TIP-Sz scores obtained from 100 patients who met the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria for schizophrenia.

Results

The factor analysis extracted four factors that were deemed clinically pertinent, which we labeled: disorganization, social cooperativeness, functional capacity, and emotional state. The items exhibited cross-loadings on the first three factors (i.e., some items loaded on more than one factor). In particular, the 'behavioral dyscontrol and disorganization,' 'insight and reality testing,' and 'overall prognostic impression' items had comparable cross-loadings on all of the first three factors. The emotional state factor was distinct from the other factors in that the items loading on it did not cross-load on other factors.

Conclusion

The TIP-Sz scale comprises factors that are associated with the psychosocial functioning and emotional state of patients, which are important outcome parameters for successful treatment of the disease.

Who's left? Symptoms of schizophrenia that predict clinical trial dropout

A significant proportion of subjects drop out of medium to long-term clinical studies prior to trial completion. This may bias reported study outcomes and reduce the statistical power of analyses. There is therefore a need for researchers to better understand the characteristics of dropout populations to increase completion rates. Data from a set of participants recruited as part of a 24-week placebo-controlled trial were used to determine the relationship between the five Lindenmayer factors of positive, negative, cognitive, anxiety/depression and excitement symptoms and dropout at trial completion. Results indicated that the rate of trial dropout was significantly predicted by scores on the negative Lindenmayer factor (X² (6, N = 126) = 15.60, p < .05). By trial completion, participants with 'high' negative Lindenmayer scores dropped out at a rate of 64%, whereas 'medium' and 'low' groups dropped out at 43% and 30%, respectively. No other relationship between symptom severity scores and dropout across the remaining Lindenmayer factors was found. These findings reflect important considerations for the future design of clinical trials involving people with schizophrenia and may also provide clues into treatment compliance issues more generally.

Assessing recovery from schizophrenia as an individual process. A review of self-report instruments

OBJECTIVE

Studies investigating indicators of recovery from schizophrenia yielded two concepts of recovery. The first is the reduction of psychiatric symptoms and functional disabilities ('clinical recovery'), while the second describes the individual adaptation process to the threat posed to the individual sense of self by the disorder and its negative consequences ('personal recovery'). Evidence suggests that both perceptions contribute substantially to the understanding of recovery and require specific assessment and therapy. While current reviews of measures of clinical recovery exist, measures of personal recovery have yet to be investigated. Considering the steadily growing literature on recovery, this article gives an update about existing measures assessing personal recovery.

METHOD

A literature search for instruments was performed using Medline, Embase, PsycINFO&PSYNDEXPlus, ISI Web of Knowledge, and Cochrane Library. Inclusion criteria were: (1) quantitative self-report measures; (2) specifically developed for adults with schizophrenia or schizoaffective disorder or at least applied to individuals suffering from severe mental illness; (3) empirically tested psychometric properties and/or published in a peer-reviewed, English-language journal. Instruments were evaluated with regard to psychometric properties (validity and reliability) and issues of application (user and administrator friendliness, translations).

RESULTS

Thirteen instruments met the inclusion criteria. They were individually described and finally summarized in a table reflecting the pros and cons of each instrument. This may enable the reader to make an evidence-based choice for a questionnaire for a specific application.

CONCLUSION

The Recovery Assessment Scale is possibly the best currently available measure of personal recovery when all evaluation criteria are included. However, the ratings listed in the current paper depended on the availability of information and the quality of available reports of previous assessment of the measurement properties. Considering the significant amount of information lacking and inconsistent findings, further research on the reviewed measures is perhaps more important than the development of new measures of personal recovery.

Use of non-parametric item response theory to develop a shortened version of the Positive and Negative Syndrome Scale (PANSS)

BACKGROUND

Nonparametric item response theory (IRT) was used to examine (a) the performance of the 30 Positive and Negative Syndrome Scale (PANSS) items and their options ((levels of severity), (b) the effectiveness of various subscales to discriminate among differences in symptom severity, and (c) the development of an abbreviated PANSS (Mini-PANSS) based on IRT and a method to link scores to the original PANSS.

METHODS

Baseline PANSS scores from 7,187 patients with Schizophrenia or Schizoaffective disorder who were enrolled between 1995 and 2005 in psychopharmacology trials were obtained. Option characteristic curves (OCCs) and Item Characteristic Curves (ICCs) were constructed to examine the probability of rating each of seven options within each of 30 PANSS items as a function of subscale severity, and summed-score linking was applied to items selected for the Mini-PANSS.

RESULTS

The majority of items forming the Positive and Negative subscales (i.e. 19 items) performed very well and discriminate better along symptom severity compared to the General Psychopathology subscale. Six of the seven Positive Symptom items, six of the seven Negative Symptom items, and seven out of the 16 General Psychopathology items were retained for inclusion in the Mini-PANSS. Summed score linking and linear interpolation was able to produce a translation table for comparing total subscale scores of the Mini-PANSS to total subscale scores on the original PANSS. Results show scores on the subscales of the Mini-PANSS can be linked to scores on the original PANSS subscales, with very little bias.

CONCLUSIONS

The study demonstrated the utility of non-parametric IRT in examining the item properties of the PANSS and to allow selection of items for an abbreviated PANSS scale. The comparisons between the 30-item PANSS and the Mini-PANSS revealed that the shorter version is comparable to the 30-item PANSS, but when applying IRT, the Mini-PANSS is also a good indicator of illness severity.

Is there a linear relationship between the Brief Psychiatric Rating Scale and the Clinical Global Impression-Schizophrenia scale? A retrospective analysis

BACKGROUND

Although the Brief Psychiatric Rating Scale (BPRS) is widely used for evaluating patients with schizophrenia, it has limited value in estimating the clinical weight of individual symptoms. The aim of this study was 4-fold: 1) to investigate the relationship of the BPRS to the Clinical Global Impression-Schizophrenia Scale (CGI-SCH), 2) to express this relationship in mathematical form, 3) to seek significant symptoms, and 4) to consider a possible modified BPRS subscale.

METHODS

We evaluated 150 schizophrenia patients using the BPRS and the CGI-SCH, then examined the scatter plot distribution of the two scales and expressed it in a mathematical equation. Next, backward stepwise regression was performed to select BPRS items that were highly associated with the CGI-SCH. Multivariate regression was conducted to allocate marks to individual items, proportional to their respective magnitude. We assessed the influence of modifications to the BPRS in terms of Pearson's r correlation coefficient and r-squared to evaluate the relationship between the two scales. Utilizing symptom weighting, we assumed a possible BPRS subscale.

RESULTS

By plotting the scores for the two scales, a logarithmic curve was obtained. By performing a logarithmic transformation of the BPRS total score, the curve was modified to a linear distribution, described by [CGI-SCH] = 7.1497 × log10[18-item BPRS] - 6.7705 (p < 0.001). Pearson's r for the relationship between the scales was 0.7926 and r-squared was 0.7560 (both p < 0.001). Applying backward stepwise regression using small sets of items, eight symptoms were positively correlated with the CGI-SCH (p < 0.005) and the subset gave Pearson's r of 0.8185 and r-squared of 0.7198. Further selection at the multivariate regression yielded Pearson's r of 0.8315 and r-squared of 0.7036. Then, modification of point allocation provided Pearson's r of 0.8339 and r-squared of 0.7036 (all these p < 0.001). A possible modified BPRS subscale, "the modified seven-item BPRS", was designed.

CONCLUSIONS

Limited within our data, a logarithmic relationship was assumed between the two scales, and not only individual items of the BPRS but also their weightings were considered important for a linear relationship and improvement of the BPRS for evaluating schizophrenia.

The Impact of Symptomatology on Response to a Health Promoting Intervention among Older Adults with Schizophrenia

Purpose

To explore the relationship between the symptoms of schizophrenia experienced by older persons diagnosed with schizophrenia and type 2 diabetes mellitus and their response to a health promoting intervention.

Methods

Secondary data analysis of data obtained from a lifestyle intervention program that recruited participants over age 40 with schizophrenia or schizoaffective disorder and type 2 diabetes mellitus from board-and-care facilities and day treatment programs. Participants had been randomly assigned to a 24-week diabetes awareness and rehabilitation training (DART; n = 32) or a usual care plus information (UCI; n = 32) comparison group. Baseline and 6-month (intervention completion) assessments included a diabetes knowledge test (DKT), diabetes self-efficacy measured by the diabetes empowerment scale (DES), and symptomatology defined by the Positive and Negative Syndrome Scale (PANSS). Simple linear regression models in 3 steps were used to analyze the data.

Results

A significant condition by symptom interaction was found for DKT. The difference between change in knowledge for DART and UCI groups depended on the prevalence and severity of the total, negative, and general symptoms. There was no significant condition by positive symptom interaction for DKT. A significant main effect was found between total, negative, positive, and general symptoms in the total sample for improvement in DES scores. Higher prevalence and severity of symptoms was negatively associated with improvement in DES scores.

Conclusion

Researchers need to consider the impact of schizophrenia symptoms in response to health promoting interventions.

The thalamus and schizophrenia: current status of research

The thalamus provides a nodal link for multiple functional circuits that are impaired in schizophrenia (SZ). Despite inconsistencies in the literature, a meta analysis suggests that the volume of the thalamus relative to that of the brain is decreased in SZ. Morphometric neuroimaging studies employing deformation, voxel-based and region of interest methodologies suggest that the volume deficit preferentially affects the thalamic regions containing the anterior and mediodorsal nuclei, and the pulvinar. Postmortem design-based stereological studies have produced mixed results regarding volume and neuronal deficits in these nuclei. This review examines those aspects of thalamic circuitry and function that suggest salience to SZ. Evidence for anomalies of thalamic structure and function obtained from postmortem and neuroimaging studies is then examined and directions for further research proposed.