Inflammatory markers in antipsychotic-naïve patients with nonaffective psychosis and deficit vs. nondeficit features

Exercise4Psychosis: A randomised control trial assessing the effect of moderate-to-vigorous exercise on inflammatory biomarkers and negative symptom profiles in men with first-episode psychosis

INTRODUCTION

First-Episode Psychosis (FEP) is a devastating mental health condition that commonly emerges during early adulthood, and is characterised by a disconnect in perceptions of reality. Current evidence suggests that inflammation and perturbed immune responses are involved in the pathology of FEP and may be associated specifically with negative symptoms. Exercise training is a potent anti-inflammatory stimulus that can reduce persistent inflammation, and can improve mood profiles in general populations. Therefore, exercise may represent a novel adjunct therapy for FEP. The aim of this study was to assess the effect of exercise on biomarkers of inflammation, negative symptoms of psychosis, and physiological health markers in FEP.

METHODS

Seventeen young males (26.67 ± 6.64 years) were recruited from Birmingham Early Intervention in Psychosis Services and randomised to a 6-week exercise programme consisting of two-to-three sessions per week that targeted 60-70 % heart-rate max (HRMax), or a treatment as usual (TAU) condition. Immune T-helper (Th-) cell phenotypes and cytokines, symptom severity, functional wellbeing, and cognition were assessed before and after 6-weeks of regular exercise.

RESULTS

Participants in the exercise group (n = 10) achieved 81.11 % attendance to the intervention, with an average exercise intensity of 67.54 % ± 7.75 % HRMax. This led to favourable changes in immune cell phenotypes, and a significant reduction in the Th1:Th2 ratio (-3.86 %) compared to the TAU group (p = 0.014). After the exercise intervention, there was also a significant reduction in plasma IL-6 concentration (-22.17 %) when compared to the TAU group (p = 0.006). IL-8, and IL-10 did not show statistically significant differences between the groups after exercise. Symptomatically, there was a significant reduction in negative symptoms after exercise (-13.54 %, Positive and Negative Syndrome Scale, (PANSS) Negative) when compared to the TAU group (p = 0.008). There were no significant change in positive or general symptoms, functional outcomes, or cognition (all p > 0.05).

DISCUSSION

Regular moderate-to-vigorous physical activity is feasible and attainable in clinical populations. Exercise represents a physiological tool that is capable of causing significant inflammatory biomarker change and concomitant symptom improvements in FEP cohorts, and may be useful for treatment of symptom profiles that are not targeted by currently prescribed antipsychotic medication.

[The role of immuno-inflammatory factors in the development of negative symptoms in schizophrenia]

The literature review assessed the data obtained over the past 10 years on the relationship between inflammatory markers and the severity of negative symptoms in schizophrenia. A systematic search of the PubMed, Mendeley, and eLibrary databases was conducted in accordance with the PRISMA guidelines. Of the 407 publications found, 7 studies were selected by keywords that quantitatively assessed the relationship between the concentration of inflammatory markers and the severity of negative disorders in schizophrenia. Three publications reported statistically significant positive correlations between the level of tumor necrosis factor TNF-α and the scores of the negative subscale of the Positive and Negative Symptoms Scale (PANSS), two studies showed moderate correlations and weak correlations were reported in two publications. Two studies recorded reliable moderate and weak associations of negative symptoms with IL-1β, IL-6, IL-8, IL-10. A relationship was found between negative symptoms and the concentration of C-reactive protein, autoantibodies to neurotrophin S100b and myelin basic protein (MBP). In addition, immune-inflammatory indices of the neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), and the Systemic Immune Inflammation Index (SII), which generally reflect the direction of the inflammatory response, were associated with the severity of negative disorders. The analyzed studies provided convincing data on the presence of reliable relationships between a number of cytokines and the severity of negative symptoms, which confirms previously published literature data on the pathogenetic role of neuroinflammation in the formation of negative symptoms.

Predictors of successful anti-inflammatory drug trials in patients with schizophrenia: A meta-regression and critical commentary

Given evidence pointing toward a role for immune dysregulation in the pathogenesis of schizophrenia, anti-inflammatory agents are promising adjunctive treatments that have potential to support a causal relationship for inflammation and psychopathology and lead to novel treatments for individuals. Indeed, previous meta-analyses have demonstrated small-to-medium effect sizes (ES) in favor of various anti-inflammatory agents, though there is significant heterogeneity and challenges in the interpretation of this literature. Identifying predictors, including sociodemographic variables, trial duration, and/or symptoms themselves, of successful anti-inflammatory trials may help identify which patients who might benefit from these compounds. We performed a meta-regression analysis of 63 adjunctive anti-inflammatory trial arms (2232 patients randomized to adjunctive anti-inflammatory agents and 2207 patients randomized to placebo).Potential predictors of effect size estimates for changes in psychopathology scores from baseline to endpoint included geography, trial duration, sample size, age, sex, race, smoking, body mass index, illness duration, age of onset of psychosis, study quality score and psychopathology scores (total and subscale) at baseline. Geography (β = 0.31, p = 0.011), smaller sample size (β = 0.33, p = 0.009), and higher study quality score (β = 0.44, p < 0.001) were significant predictors of larger ES estimates for change in total psychopathology in favor of anti-inflammatory agents. Smaller sample size (β = 0.37, p = 0.034) and higher study quality score (β = 0.55, p = 0.003) were significant predictors of larger ES estimates for change in negative psychopathology in favor of anti-inflammatory agents. Higher study quality score (β = 0.46, p = 0.019) was a significant predictor of larger ES estimates for change in general psychopathology in favor of anti-inflammatory agents. These findings should be interpreted with caution given concerns of publication bias regarding the geographic differences and small study effects. The lack of an association with other demographic variables should be seen as a primary limitation of the literature that needs to be considered in future studies. The association with study quality score suggests that future anti-inflammatory trials must consider demographic variables known to be associated with inflammation (e.g., BMI and smoking) and evidence of increased baseline inflammation should be incorporated in study design. Moreover, evidence of target engagement and endpoints thoughts to be associated with increased inflammation should be considered as well.

Network analysis of inflammation and symptoms in recent onset schizophrenia and the influence of minocycline during a clinical trial

Attempts to delineate an immune subtype of schizophrenia have not yet led to the clear identification of potential treatment targets. An unbiased informatic approach at the level of individual immune cytokines and symptoms may reveal organisational structures underlying heterogeneity in schizophrenia, and potential for future therapies. The aim was to determine the network and relative influence of pro- and anti-inflammatory cytokines on depressive, positive, and negative symptoms. We further aimed to determine the effect of exposure to minocycline or placebo for 6 months on cytokine-symptom network connectivity and structure. Network analysis was applied to baseline and 6-month data from the large multi-center BeneMin trial of minocycline (N = 207) in schizophrenia. Pro-inflammatory cytokines IL-6, TNF-α, and IFN-γ had the greatest influence in the inflammatory network and were associated with depressive symptoms and suspiciousness at baseline. At 6 months, the placebo group network connectivity was 57% stronger than the minocycline group, due to significantly greater influence of TNF-α, early wakening, and pathological guilt. IL-6 and its downstream impact on TNF-α, and IFN-γ, could offer novel targets for treatment if offered at the relevant phenotypic profile including those with depression. Future targeted experimental studies of immune-based therapies are now needed.

Association of empathy with clinical symptoms and cognitive function in Chinese chronic schizophrenia patients with and without deficit syndrome

BACKGROUND

Patients with deficit syndrome (DS) are known to experience cognitive impairment. However, there is no consistent conclusion on the impairment of neurocognitive features in DS patients, and no studies have examined their empathy. The purpose of this study was to compare neurocognition and empathy in patients with DS and non-DS schizophrenia.

METHODS

Totally, 665 patients with chronic schizophrenia were enrolled. DS patients were identified by the Proxy Scale for Deficit Syndrome (PDS). Neurocognition and social cognition were assessed by Repeatable Battery for the measurement of Neuropsychological Status (RBANS) and the Interpersonal Reactivity Index (IRI), respectively. In addition, psychopathological symptom severity was assessed by the Positive and Negative Syndrome Scale (PANSS).

RESULTS

Participants included 150 patients with DS and 140 patients with non-DS. DS patients performed significantly worse on the all RBANS domain (except for visuospatial) and total scores as well as IRI scores. Regression analysis showed that PANSS general psychopathology and education were associated with RBANS total score in the DS group (adjusted R² = 0.29), while education and PANSS negative symptoms were correlated with RBANS total score in non-DS patients (adjusted R² = 0.33). In the non-DS group, suicide attempts and PANSS negative symptom score were independently associated with IRI total score (adjusted R² = 0.06), whereas in the DS group, no variable was associated with IRI total score.

CONCLUSIONS

Our findings suggest that patients with DS may have poor neurocognitive and empathy performance. In chronic schizophrenia patients, negative symptoms may play a different role in cognition between DS and non-DS groups.

Differences in inflammatory marker profiles and cognitive functioning between deficit and nondeficit schizophrenia

Deficit schizophrenia (DS) patient is a homogenous subtype of schizophrenia that includes primary and enduring negative symptoms. This study aimed to compare the differences in cognitive functioning and plasma levels of C-reactive protein (CRP) and inflammatory cytokines among DS patients, nondeficit schizophrenia (NDS) patients, and healthy controls (HCs). A total of 141 schizophrenia patients and 67 HCs were included in this study. The schizophrenia patients were divided into DS (N= 51) and NDS (N=90) groups based on the Proxy for the Deficit Syndrome Scale (PDS). The Positive and Negative Syndrome Scale (PANSS) and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) were used to evaluate the clinical symptoms and cognitive performances, respectively. The plasma level of CRP, IL-1β, Il-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-17, TNF-α, and IFN-γ were measured using enzyme-linked immunosorbent assays (ELISAs). Our results showed that DS patients had the worst cognitive performance, especially in the immediate memory, attention, and language dimensions, compared to the NDS and HC groups. Compared to the HCs group, DS patients had higher levels of CRP, IL-1β, IL-6, IL-8, IFN-γ, and total proinflammatory cytokines, and NDS patients had higher levels of IL-1β, IFN-γ, and proinflammatory cytokines. We also found that CRP levels were significantly increased in DS patients compared to NDS patients. Moreover, stepwise logistic regression analysis revealed that CRP is an independent risk factor for DS. Sex stratification analysis showed significant differences in almost all cytokines in female samples but not in male samples. The significant differences in cognitive performance and inflammatory components among groups suggest that deficit syndrome is an independent endophenotype of schizophrenia patients with unique immune-inflammatory features, but may have sex characteristics.

Peripheral biomarkers of treatment-resistant schizophrenia: Genetic, inflammation and stress perspectives

Treatment-resistant schizophrenia (TRS) often results in severe disability and functional impairment. Currently, the diagnosis of TRS is largely exclusionary and emphasizes the improvement of symptoms that may not be detected early and treated according to TRS guideline. As the gold standard, clozapine is the most prescribed selection for TRS. Therefore, how to predict TRS in advance is critical for forming subsequent treatment strategy especially clozapine is used during the early stage of TRS. Although mounting studies have identified certain clinical factors and neuroimaging characteristics associated with treatment response in schizophrenia, the predictors for TRS remain to be explored. Biomarkers, particularly for peripheral biomarkers, show great potential in predicting TRS in view of their predictive validity, noninvasiveness, ease of testing and low cost that would enable their widespread use. Recent evidence supports that the pathogenesis of TRS may be involved in abnormal neurotransmitter systems, inflammation and stress. Due to the heterogeneity of TRS and the lack of consensus in diagnostic criteria, it is difficult to compare extensive results among different studies. Based on the reported neurobiological mechanisms that may be associated with TRS, this paper narratively reviews the updates of peripheral biomarkers of TRS, from genetic and other related perspectives. Although current evidence regarding biomarkers in TRS remains fragmentary, when taken together, it can help to better understand the neurobiological interface of clinical phenotypes and psychiatric symptoms, which will enable individualized prediction and therapy for TRS in the long run.

Could CRP be a differential biomarker of illness stages in schizophrenia? A systematic review and meta-analysis

BACKGROUND

Patients with schizophrenia display peripheral inflammation but the impact of illness phase is not clear. Our meta-analysis investigated the difference in CRP levels between patients with schizophrenia and controls according to their illness phase.

METHODS

After a systematic search, all studies measuring CRP in patients with schizophrenia and controls were included. Standardized mean differences were calculated between patients and controls according to illness phase. The influence of sociodemographic and clinical variables on our results was investigated using a meta-regression analysis.

RESULTS

Fifty studies were included in this meta-analysis. Patients with schizophrenia had higher CRP levels than controls in the acute (p < 0.00001) and stable (p < 0.00001) stage of their disease. Patients with acute exacerbation of schizophrenia had higher CRP levels than stable patients (p = 0.02) but this difference did not persist when considering antipsychotic-medicated patients in both phases. Meta-regressions found that the increase of CRP in acutely ill patients as compared to controls was influenced by age (p < 0.01), BMI (p = 0.01) and first episode (p = 0.02), whereas the increase in CRP levels of stable patients as compared to controls was moderated by BMI (p = 0.004).

CONCLUSIONS

In conclusion, this meta-analysis provides strong evidence that patients with schizophrenia have higher CRP levels than controls, but also show an increase in inflammatory response in the acute stage of the disease as compared to the stable stage. CRP could thus be considered as a state marker and a trait marker of the disease.

Inflammation in first-episode psychosis: The contribution of inflammatory biomarkers to the emergence of negative symptoms, a systematic review and meta-analysis

OBJECTIVE

To provide a comprehensive analysis of cytokine perturbations in antipsychotic-naïve first-episode psychosis (FEP) populations and assess the relationship between inflammatory biomarkers and negative symptom severity.

METHODS

A systematic review and meta-analysis following PRISMA guidelines were conducted. A total of 1042 records were identified via systematic search of EMBASE, MEDLINE and APA PsycInfo databases. Sixteen studies met the inclusion criteria and were eligible for inclusion in the review. Ten of these studies had sufficient data for inclusion in a random effects, pooled-effect meta-analysis.

RESULTS

A significant and large effect size was reported for IFN-γ, IL-6 and IL-12, and a moderate effect size reported for IL-17 (p = <0.05) in people with antipsychotic naive first episode psychosis, compared to healthy controls, suggesting a significant elevation in proinflammatory cytokine concentration. Non-significant effect sizes were reported for TNF-α, IL-1β, IL-2, IL-4, IL-8 and IL-10 (p = >0.05). Regarding proinflammatory cytokines and relationships to negative symptomology, moderate positive relationships were reported for negative symptoms and IL-1β, IL-2, IL-6 and TNF-α, across four studies. For anti-inflammatory cytokines, one strong and one weak-to-moderate negative relationship was described for IL-10 and negative symptoms. Contrastingly, a strong positive relationship was reported for IL-4 and negative symptoms.

CONCLUSION

There is evidence of significantly elevated proinflammatory cytokines in antipsychotic-naïve FEP populations, alongside promising findings from cohort data suggesting an interaction between inflammation and primary negative symptomology. Future studies should seek to come to a consensus on a panel of cytokines that relate most specifically to negative symptoms, and consider longitudinal studies to investigate how cytokine fluctuations may relate to exacerbation of symptoms.

Psychopathology and Stem Cell Mobilization in Ultra-High Risk of Psychosis and First-Episode Psychosis Patients

Although regenerative and inflammatory processes are involved in the etiopathogenesis of many psychiatric disorders, their roles are poorly understood. We investigate the potential role of stem cells (SC) and factors influencing the trafficking thereof, such as complement cascade (CC) components, phospholipid substrates, and chemokines, in the etiology of schizophrenia. We measured sphingosine-1-phosphate (S1P), stromal-derived factor 1 (SDF-1), and CC cleavage fragments (C3a, C5a, and C5b-C9; also known as the membrane attack complex) in the peripheral blood of 49 unrelated patients: 9 patients with ultra-high risk of psychosis (UHR), 22 patients with first-episode psychosis (FEP), and 18 healthy controls (HC). When compared with the HC group, the UHR and FEP groups had higher levels of C3a. We found no significant differences in hematopoietic SC, very small embryonic-like stem cell (VSEL), C5a, S1P, or SDF-1 levels in the UHR and FEP groups. However, among FEP patients, there was a significant positive correlation between VSELs (CD133+) and negative symptoms. These preliminary findings support the role of the immune system and regenerative processes in the etiology of schizophrenia. To establish the relevance of SC and other factors affecting the trafficking thereof as potential biomarkers of schizophrenia, more studies on larger groups of individuals from across the disease spectrum are needed.

Serum BDNF levels, glycolipid metabolism in deficit schizophrenia: A case-control study

BACKGROUND

Few studies have compared serum BDNF and glycolipid profiles in patients with deficit schizophrenia (DS) and non-deficit schizophrenia (NDS). We aimed to compare BDNF and glycolipid profiles between DS and NDS patients and healthy controls, and to investigate the relationship between BDNF, glycolipid profiles in DS and NDS patients.

METHODS

A total of 591 patients with chronic schizophrenia (SZ) and 238 healthy controls participated in this study. According to Proxy for the Deficit Syndrome Scale, SZ patients were divided into DS (n = 158) and NDS (n = 273) patients. Psychiatric symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS). Serum BDNF levels were measured using enzyme-linked immunosorbent assay (ELISA).

RESULTS

BDNF levels were significantly lower in SZ patients than those in healthy controls (7.81 ± 2.98 ng/ml vs. 11.96 ± 2.29 ng/ml, P < 0.01). Furthermore, BDNF levels were lower in DS group than those in NDS group (P = 0.007, OR = 0.846, 95% CI = 0.750-0.955). Lower triglyceride levels were also an independent predictor for DS patients (P = 0.007, OR = 0.846, 95% CI = 0.750-0.955). Serum BDNF levels were negatively associated with the severity of deficit syndrome in SZ patients (β = -1.151, t = -2.559, P = 0.011). In DS group, triglycerides were associated with PANSS negative subscore (β = -0.262, t = -2.994, P = 0.003) and depressive factor subscore (β = 0.282, t = 2.146, P = 0.035).

CONCLUSION

Serum BDNF and triglycerides may be informative biomarkers of DS in SZ patients. The differences in glycolipid metabolism patterns between DS and NDS patients indicate that deficit syndrome is an independent endophenotype of SZ patients.

Redefining the Cut-Off Ranges for TSH Based on the Clinical Picture, Results of Neuroimaging and Laboratory Tests in Unsupervised Cluster Analysis as Individualized Diagnosis of Early Schizophrenia

Thyroid abnormalities, including mild forms of hypothyroidism and hyperthyroidism, are reported as risk factors for the development of a number of neuropsychiatric disorders, including schizophrenia. The diagnostic process still takes into account the extreme ranges of the accepted reference values for serum TSH since the concentration of free thyroxine in the serum does not change by definition. TSH mU/L cut-off values in psychiatric patients are currently clinically considered in the case of extremely high serum TSH levels (>4.0 mU/L). The results obtained in this study suggest that the clinically significant value has a lower TSH cut-off point with an upper limit of 2–2.5 mU/L. The criteria for the differential diagnosis of patients with schizophrenia, however, mainly take into account statutory reference ranges without a background related to the history of thyroid diseases in the family. The results indicate the need to lower the upper cut-off values for TSH among patients with early psychosis, which is related to the potential clinical significance of the obtained values both in the field of clinical evaluation and neuroimaging and laboratory evaluation parameters. The cut-off points obtained with the prior available knowledge coincided with the values established in the unsupervised clustering method, which further confirms the legitimacy of their use in the individualized diagnosis strategy of schizophrenia.

[Molecular-genetic and immunological aspects of the formation of psychopathological symptoms in schizophrenia]

The authors present the data indicating that the formation of psychopathological symptoms of schizophrenia is due to complex and diverse genetic factors associated with various functional and metabolic pathways at different stages of ontogenesis. Despite the fact that at present the genetic basis of positive and negative symptoms as the main pathophysiological manifestations of schizophrenia remains largely unknown, the current level of research allows the identification of some common and unique associations for positive and negative disorders. Based on the analysis of the literature, the specificity of the association of genetic variants with negative symptoms of schizophrenia is shown. It has been also suggested that genes of the immune system may be specifically associated with negative symptoms of schizophrenia. The relevance of studying the relationship of immune system genes, in particular, pro- and anti-inflammatory cytokines, with dimensional characteristics of negative symptoms (abulia-apathy and expressive deficit) is substantiated. Studies of this type have not yet been conducted, despite accumulating data indicating that the heterogeneity of negative symptoms is based on different neurobiological mechanisms. It is concluded that the immunological and molecular genetic study of the subdomains of psychopathological symptoms can be promising as part of the transition to deep phenotyping, which seems to be especially relevant for the study of such an extremely heterogeneous disease from a clinical point of view as schizophrenia. The development of this area is important for solving the problems of precision medicine, which aims to provide the most effective therapy for a particular patient by stratifying the disease into subclasses, taking into account their biological basis.

The Role of Cytokines in the Pathogenesis of Schizophrenia

Schizophrenia is a chronic mental illness of unknown etiology. A growing and compelling body of evidence implicates immunologic dysfunction as the key element in its pathomechanism. Cytokines, whose altered levels have been increasingly reported in various patient populations, are the major mediators involved in the coordination of the immune system. The available literature reports both elevated levels of proinflammatory as well as reduced levels of anti-inflammatory cytokines, and their effects on clinical status and neuroimaging changes. There is evidence of at least a partial genetic basis for the association between cytokine alterations and schizophrenia. Two other factors implicated in its development include early childhood trauma and disturbances in the gut microbiome. Moreover, its various subtypes, characterized by individual symptom severity and course, such as deficit schizophrenia, seem to differ in terms of changes in peripheral cytokine levels. While the use of a systematic review methodology could be difficult due to the breadth and diversity of the issues covered in this review, the applied narrative approach allows for a more holistic presentation. The aim of this narrative review was to present up-to-date evidence on cytokine dysregulation in schizophrenia, its effect on the psychopathological presentation, and links with antipsychotic medication. We also attempted to summarize its postulated underpinnings, including early childhood trauma and gut microbiome disturbances, and propose trait and state markers of schizophrenia.

A meta-analysis of blood and salivary cortisol levels in first-episode psychosis and high-risk individuals

Dysregulated cortisol responses and glucose metabolism have been reported in psychosis. We performed a random-effects meta-analysis of cortisol responses in first-episode psychosis (FEP) and psychosis risk states, taking into consideration glucose metabolism. A total of 47 studies were included. Unstimulated blood cortisol levels were significantly higher (g = 0.48, 95 %CI: 0.25-0.70, p < 0.001) in FEP, but not in psychosis risk states (g = 0.39, 95 %CI: -0.42-1.21, p = 0.342), compared to controls. Cortisol awakening response (CAR) was attenuated in FEP (g = -0.40, 95 %CI: -0.68 - -0.12, p = 0.006), but not in psychosis risk states (p = 0.433). Glucose and insulin levels were positively correlated with unstimulated blood cortisol levels in FEP. Our meta-analysis supports previous findings of elevated blood cortisol levels and attenuated CAR in FEP. Future research should focus on identifying the common denominators for alterations in stress hormones and glucose metabolism.

White Matter Integrity of the Corpus Callosum and Psychopathological Dimensions in Deficit and Non-Deficit Schizophrenia Patients

Deficit syndrome (DS) is a subtype of schizophrenia characterized by primary persistent negative symptoms. The corpus callosum (CC) appears to be related to psychopathology in schizophrenia. This study assessed white matter integrity in the CC using diffusion tensor imaging (DTI) in deficit and non-deficit schizophrenia (NDS) patients. We also investigated the psychopathological dimensions of schizophrenia and their relationship to CC integrity. Fifteen DS patients, 40 NDS patients, and 30 healthy controls (HC) underwent psychiatric evaluation and neuroimaging. We divided the CC into five regions and assessed their fractional anisotropy (FA) and mean diffusivity (MD). Psychopathology was assessed with the Positive and Negative Syndrome Scale. DS patients had lower FA than NDS patients and HC, and higher MD in Region 5 of the CC than did HC. NDS patients had higher MD in Region 4 of the CC. The patient groups differed in terms of negative symptoms. After differentiating clinical groups and HC, no significant correlations were observed between DTI measures and psychopathological symptoms. Our results suggest that DS and NDS are characterized by minor impairments of the posterior CC. We confirmed that DS patients have greater negative psychopathology than NDS patients. Our results are preliminary, and further studies are needed.

Mechanisms Underlying the Comorbidity of Schizophrenia and Type 2 Diabetes Mellitus

The mortality rate of patients with schizophrenia is high, and life expectancy is shorter by 10 to 20 years. Metabolic abnormalities including type 2 diabetes mellitus (T2DM) are among the main reasons. The prevalence of T2DM in patients with schizophrenia may be epidemiologically frequent because antipsychotics induce weight gain as a side effect and the cognitive dysfunction of patients with schizophrenia relates to a disordered lifestyle, poor diet, and low socioeconomic status. Apart from these common risk factors and risk factors unique to schizophrenia, accumulating evidence suggests the existence of common susceptibility genes between schizophrenia and T2DM. Functional proteins translated from common genetic susceptibility genes are known to regulate neuronal development in the brain and insulin in the pancreas through several common cascades. In this review, we discuss common susceptibility genes, functional cascades, and the relationship between schizophrenia and T2DM. Many genetic and epidemiological studies have reliably associated the comorbidity of schizophrenia and T2DM, and it is probably safe to think that common cascades and mechanisms suspected from common genes' functions are related to the onset of both schizophrenia and T2DM. On the other hand, even when genetic analyses are performed on a relatively large number of comorbid patients, the results are sometimes inconsistent, and susceptibility genes may carry only a low or moderate risk. We anticipate future directions in this field.

Inflammation and Oxidative Stress in Deficit Schizophrenia

Introduction

Differences in parameters related to inflammatory and oxidative stress in deficit (DS) and nondeficit schizophrenia (non-DS) may support the DS/non-DS categorization of schizophrenia. For DS patients, non-DS patients, and for healthy controls, this study aims to evaluate the serum levels of: proinflammatory cytokines of interleukin (IL) 1β, tumor necrosis factor (TNF) α, Interferon (IFN) γ, IL-12, and IL-17; anti-inflammatory cytokines of IL-10, IFN-α, and transforming growth factor (TGF) β; and antioxidant biomarkers of paraoxonase1 (PON1) and Total Antioxidant Capacity (TAOC).

Method

Serum IL-1β, TNF-α, IFN-γ, IL-12, IL-17, IL-10, IFN-α, TGF-β, PON1 and TAOC levels were measured and performed in DS (n=26), non-DS (n=28), and healthy control (n=28) groups.

Results

Patients in the DS group had higher IL-17 levels than the non-DS group did. TGF-β values for both patient groups were significantly higher than those of the controls. PON1 and TAOC values for both patient groups were significantly lower than those of the controls.

Conclusion

Our findings may be evidence for the consideration that DS reflects a coherent entity within schizophrenia. Increased levels of IL-17 from pro-inflammatory cytokines may be related with DS.

Assessing causal links between metabolic traits, inflammation and schizophrenia: a univariable and multivariable, bidirectional Mendelian-randomization study

BACKGROUND

Blood immunoreactive biomarkers, such as C-reactive protein (CRP), and metabolic abnormalities have been associated with schizophrenia. Studies comprehensively and bidirectionally probing possible causal links between such blood constituents and liability to schizophrenia are lacking.

METHODS

To disentangle putative causal links between CRP blood levels and schizophrenia in both directions, we conducted multiple univariable Mendelian-randomization (MR) analyses, ranging from fixed-effect to inverse variance-weighted (IVW), weighted-median, MR Egger and generalized summary-data-based Mendelian-randomization (GSMR) models. To prioritize metabolic risk factors for schizophrenia, a novel multivariable approach was applied: multivariable Mendelian-randomization-Bayesian model averaging (MR-BMA).

RESULTS

All forward univariable MR analyses consistently showed that CRP has a protective effect on schizophrenia, whereas reverse MR analyses consistently suggested absent causal effects of schizophrenia liability on CRP blood levels. Using MR-BMA, as the top protective factors for schizophrenia we prioritized leucine and as the prime risk-factor triglycerides in medium very-low-density lipoprotein (VLDL). The five best-performing MR-BMA models provided one additional risk factor: triglycerides in large VLDL; and two additional protective factors: citrate and lactate.

CONCLUSIONS

Our results add to a growing body of literature hinting at metabolic changes-in particular of triglycerides-independently of medication status in schizophrenia. We also highlight the absent effects of genetic liability to schizophrenia on CRP levels.

Increased interleukin 18 activity in adolescents with early-onset psychosis is associated with cortisol and depressive symptoms

OBJECTIVE

Evidence indicates that the pathophysiology of adult psychosis involves immune dysregulation, but its associations with stress are often not considered. The inflammatory cytokine interleukin (IL)-18, which is elevated in adult schizophrenia, is suggested to be sensitive to stress. We compared the associations of IL-18 with cortisol and clinical variables in adolescents with early-onset psychosis (EOP) aged 12-18 years and age-matched healthy controls (HC).

METHOD

We measured serum IL-18, IL-18 binding protein (IL-18BP), IL-18 receptor accessory protein (IL-18RAP), IL-18 receptor 1 (IL-18R1) and cortisol, and calculated the IL-18/IL-18BP ratio in patients (n = 31) and HC (n = 60). Psychotic symptoms were assessed using the Positive and Negative Syndrome Scale and depressive symptoms by the Mood and Feelings Questionnaire-Child version (MFQ-C). Bivariate correlation analysis was used to explore relationships between IL-18/IL-18BP ratio and cortisol, depression and other clinical characteristics. Hierarchical multiple linear regression analysis was used to assess their individual contributions to the variance of the IL-18/IL-18BP ratio.

RESULTS

Patients had significantly higher IL-18 levels and IL-18/IL-18BP ratios than HC, but similar IL-18BP, IL-18RAP and IL-18R1. Both cortisol (R² change = 0.05) and the MFQ-C score (R² change = 0.09) contributed significantly to the variance in IL-18/IL-18BP ratios after controlling for confounders.

CONCLUSION

We found increased IL-18 system activity in adolescents with EOP. Cortisol and depressive symptoms each contributed to the variance in the IL-18/IL-18BP ratio. Our findings support activation of inflammatory pathways in adolescent psychosis and suggest interactions between stress, inflammation and depressive symptoms in EOP.

The aetiology of social deficits within mental health disorders: The role of the immune system and endogenous opioids

The American National Institute for Mental Health (NIMH) has put out a set of research goals that include a long-term plan to identify more reliable endogenous explanations for a wide variety of mental health disorders (Insel, 2013). In response to this, we have identified a major symptom that underlies multiple mental health disorders - social bonding dysfunction. We suggest that endogenous opioid abnormalities can lead to altered social bonding, which is a symptom of various mental health disorders, including depression, schizophrenia and ASD. This article first outlines how endogenous opioids play a role in social bonding. Then we show their association with the body's inflammation immune function, and review recent literature linking inflammation to mental health 'immunophenotypes'. We finish by explaining how these immunophenotypes may be caused by alterations in the endogenous opioid system. This is the first overview of the role of inflammation across multiple disorders where we provide a biochemical explanation for why immunophenotypes might exist across diagnoses. We propose a novel mechanism of how the immune system may be causing 'sickness-type' behaviours (fatigue, appetite change, social withdrawal and inhibited motivation) in those who have these immunophenotypes. We hope that this novel aetiology can be used as a basis for future research in mental health.

Inflammation and Negative Symptoms of Schizophrenia: Implications for Reward Processing and Motivational Deficits

Negative symptoms of schizophrenia are debilitating and chronic in nature, are difficult to treat, and contribute to poor functional outcomes. Motivational deficits are a core negative symptom and may involve alterations in reward processing, which involve subcortical regions such as the basal ganglia. More specifically, dopamine-rich regions like the ventral striatum, have been implicated in these reward-processing deficits. Inflammation is one mechanism that may underlie negative symptoms, and specifically motivational deficits, via the effects of inflammatory cytokines on the basal ganglia. Previous work has demonstrated that inflammatory stimuli decrease neural activity in the ventral striatum and decrease connectivity in reward-relevant neural circuitry. The immune system has been shown to be involved in the pathophysiology of schizophrenia, and inflammatory cytokines have been shown to be altered in patients with the disorder. This paper reviews the literature on associations between inflammatory markers and negative symptoms of schizophrenia as well as the role of anti-inflammatory drugs to target negative symptoms. We also review the literature on the role of inflammation and reward processing deficits in both healthy controls and individuals with depression. We use the literature on inflammation and depression as a basis for a model that explores potential mechanisms responsible for inflammation modulating certain aspects of negative symptoms in patients with schizophrenia. This approach may offer novel targets to treat these symptoms of the disorder that are significant barriers to functional recovery and do not respond well to available antipsychotic medications.

Serum C-Reactive Protein in Patients with Deficit Schizophrenia and the Relationship with Cognitive Function

BACKGROUND

Serum levels of C-reactive protein (CRP) were measured in patients with deficit schizophrenia (DS) to confirm the association between CRP level and cognitive performance and to determine whether CRP was a new biological indicator with the potential clinical applications in DS patients.

METHODS

Three independent samples [41 DS and 50 non-deficit schizophrenia (NDS) and 30 sex- and age-matched healthy controls (HCs)] were recruited in our study. Serum CRP levels were measured by immunofluorescence. The Positive and Negative Syndrome Scale (PANSS) and alternative forms of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) were also assessed. And the relationships between serum CRP levels and both PANSS and RBANS scores were finally analyzed.

RESULTS

The results of serum CRP level were showed significantly different among the three groups and increased from the HCs to NDS patients to DS patients. There were also significant differences in the cognitive subdomain analyses among the three groups. Serum CRP levels were found positively correlated with total and negative PANSS scores, and showed negatively correlated with overall cognitive test scores in the DS samples.

CONCLUSION

Serum C-reactive protein levels and their association with cognitive performance were different between deficit schizophrenia and non-deficit schizophrenia samples, and higher serum CRP level was associated with worse cognitive performance in the DS patients. The results indicated that CRP could be a potential biomarker, and DS could be a distinct subset of schizophrenia.

An Early Developmental Marker of Deficit versus Nondeficit Schizophrenia

People with schizophrenia and primary negative symptoms (deficit schizophrenia) differ from those without such symptoms (nondeficit schizophrenia) on risk factors, course of illness, other signs and symptoms, treatment response, and biological correlates. These differences suggest that the 2 groups may also have developmental differences. A previous study found that people with schizophrenia have a wider palate than comparison subjects. We tested the hypothesis that those with deficit and nondeficit schizophrenia would differ on palate width. A dentist made blinded measurements of palate shape in deficit (N = 21) and nondeficit (N = 25) patients and control subjects (N = 127), matched for age and gender. The deficit group had significantly wider palates than either nondeficit or control subjects (respective means [standard deviation] 37.5 [3.9], 33.7 [3.1], and 34.0 [2.9]; P < .001 for both deficit/nondeficit and deficit/control comparisons, respective effect sizes 1.08 and 1.01). The nondeficit/control difference in width was not significant (P = .83), and there were no significant group differences in length or depth. The power to detect a nondeficit/control difference in width equal in size to that of the deficit/control difference in width (3.5 mm) was 0.99 and 0.92 for a 2.0-mm difference. This difference in palate width may reflect a divergence in development between deficit and nondeficit patients that occurs by the early second trimester and is consistent with the hypothesis that deficit schizophrenia is a separate disease within the syndrome of schizophrenia.

Serum Levels of High Sensitivity C-reactive Protein in Drug-naÏve First-episode Psychosis and Acute Exacerbation of Schizophrenia

OBJECTIVE

Findings about inflammatory processes in schizophrenia are increasing day by day. Inflammatory processes in schizophrenia are associated with both its etiology and clinical symptoms. Serum high-sensitivity C-reactive protein (hsCRP) is also one of these inflammatory processes. Particularly, it is thought to be closely related to clinical findings of patients with schizophrenia.

METHODS

In this study, the relationship between clinical findings of hsCRP levels of patients with drug-naÏve first-episode psychosis (FEP) and patients with schizophrenia in acute exacerbation phase is investigated. Clinical findings, psychometric properties (the Scale for the Assessment of Positive Symptoms, the Scale for the Assessment of Negative Symptoms, Brief Psychiatric Rating Scale), and hsCRP levels of patients were compared.

RESULTS

Forty-eight patients with FEP, 74 patients with schizophrenia in acute exacerbation phase and 54 healthy controlled volunteers are included in the study. The most substantial finding in the study is that there is a positive correlation between hsCRP levels and severity of positive symptoms of both patient groups, with FEP and with schizophrenia. The second most substantial finding is there is no significant difference between patients with FEP and schizophrenia, in terms of hsCRP.

CONCLUSION

The relationship between hsCRP and positive symptom severity in two groups of patients supports the inflammatory hypothesis in the etiopathogenesis of schizophrenia. This finding is supportive of close relation between inflammatory processes and clinical findings of patient with schizophrenia.

The interaction between positive schizotypy and high sensitivity C-reactive protein on response inhibition in female individuals

This study aimed to measure the associations between high sensitivity C-reactive protein (hsCRP), childhood maltreatment (CM), schizotypy and response inhibition, and to explore the interactions between hsCRP, CM and schizotypy on response inhibition. Two hundred and fourteen participants completed the Stop-Signal Task (SST), the Schizotypy Personality Questionnaire (SPQ) and the Childhood Trauma Questionnaire-Short Form (CTQ), which measured response inhibition, schizotypy and history of CM respectively. The level of hsCRP was also measured. The high schizotypy group (n = 114) had higher scores on SPQ and CTQ, higher hsCRP levels and longer SST reaction times (SSRTs) than the low schizotypy group (n = 100). In female participants, SSRT had a positive correlation with the SPQ positive factor and the disorganized SPQ factor and a positive correlation with physical neglect. HsCRP was positively correlated with the SPQ negative factor and positive SPQ factor. In male participants, SSRT was negatively correlated with emotional neglect and physical neglect. The majority of correlations between CTQ and SPQ variables were significant in both female and male participants. In female participants, hsCRP significantly predicted SSRT, and hsCRP significantly interacted with positive schizotypy in predicting SSRT.

Association of baseline inflammatory markers and the development of negative symptoms in individuals at clinical high risk for psychosis

Negative symptoms are common in individuals at clinical high-risk (CHR) for psychosis and are associated with worse functional outcomes. Inflammation may be one mechanism underlying negative symptoms. Inflammatory markers are altered in individuals at CHR and are associated with negative symptoms in patients with schizophrenia. We thus hypothesized that baseline inflammatory markers would predict the development of negative symptoms in individuals at CHR for psychosis. Thirty seven individuals from the North American Prodromal Longitudinal Study who met CHR criteria were included in the study. Inflammatory cytokines, including interferon (IFN)-λ, Interleukin (IL)-1β, IL-1 receptor antagonist (IL-1RA), IL-4, IL-6, IL-8, IL-10, and tumor necrosis factor (TNF) were measured at baseline. Negative symptoms as measured by the Scale of Prodromal Symptoms, were measured at baseline and six and twelve months. Associations between inflammatory markers and the trajectory of negative symptoms (slope) over the first year of follow-up, were assessed using linear regression models controlling for age, sex, race and depressive symptom severity (as assessed by the Calgary Depression Scale for Schizophrenia). Baseline TNF (beta = 0.361, p = 0.007) and IL-6 (beta = -0.306, p = 0.026) predicted negative symptoms slopes, along with depressive symptom severity at baseline (beta = -0.596, p = 0.000). These findings demonstrate that inflammatory cytokines may underlie the development of negative symptoms in some individuals at CHR for psychosis. TNF predicted the development of negative symptoms independent of baseline depression. Given the heterogeneity of the CHR population, the comorbidity of negative symptoms and depression in this population, and the particular challenges in treating negative symptoms, immune markers could represent potential biomarkers that underlie the development of negative symptoms, representing a potential treatment target.

First-episode schizophrenia is associated with a reduction of HERV-K methylation in peripheral blood

Human endogenous retroviruses (HERV) have been widely associated with schizophrenia etiology. Aberrant epigenetic processes may play a role in the etiology of schizophrenia. In this study, we tested whether schizophrenia patients at different stages of illness might present alterations in the levels of HERV-K methylation. We recruited 49 first-episode schizophrenia (FES) patients with 47 age- and sex-matched healthy controls (HCs), and 100 multi-episode schizophrenia (MES) patients with 50 age- and sex-matched HCs. Based on the Schedule for Deficit Schizophrenia, patients with MES were also divided into two subgroups: deficit (D-SCZ) and non-deficit schizophrenia (ND-SCZ). DNA methylation levels of HERV-K sequences were examined in peripheral blood leukocytes. We found significantly lower levels of HERV-K methylation in FES patients compared to HCs. Patients with MES and matched HCs had similar levels of HERV-K methylation. There was a significant positive correlation between chlorpromazine equivalent dosage and HERV-K methylation levels in MES patients, but not in FES individuals. No significant differences in HERV-K methylation levels between D-SCZ and ND-SCZ as well as HCs were found. Our results indicate lower HERV-K methylation levels at early stages of schizophrenia. This difference might normalize with subsequent exacerbations of schizophrenia, likely due to the effects of antipsychotics.

Elevated C-reactive protein as a predictor of a random one-year clinical course in the first ten years of schizophrenia

We investigate whether C-reactive protein (CRP) levels could predict the clinical course of patients with schizophrenia in a prospective study of 50 stable outpatients during a random 1-year period within the first 10 years of illness. Positive, negative, depressive, and cognitive symptoms were evaluated. Patients with low-grade inflammation (CRP = 3-10 mg/L; 28%) at baseline showed significant worsening of PANSS-positive and general psychopathology at 1-year follow-up compared with those with CRP ≤ 3 mg/L. Elevated CRP may be a biomarker of poor 1-year clinical course in patients with schizophrenia.

TNF-α and IL-6 are associated with the deficit syndrome and negative symptoms in patients with chronic schizophrenia

INTRODUCTION

Increased inflammatory markers have been found in patients with chronic schizophrenia, and have been associated with negative symptoms. The deficit syndrome is a distinct subtype of schizophrenia, characterized by primary and enduring negative symptoms.

METHOD

We measured inflammatory markers in patients with and without deficit schizophrenia and controls.

RESULTS

Using multivariate analyses, tumor necrosis factor (TNF)-α and interleukin-6 were associated with the deficit syndrome, and TNF-α predicted blunted affect, alogia, and total negative symptoms.

CONCLUSIONS

Findings suggest that deficit schizophrenia subtype is associated with increased inflammation and immunotherapies may be a novel target for negative symptoms.

Relation of inflammatory markers with symptoms of psychotic disorders: a large cohort study

AIMS

Immunological mechanisms may play a role in symptomatology of patients with a psychotic disorder. Besides metabolic problems and medication use, inflammatory processes that may occur due to the disorder may cause increased inflammatory markers and concurrent psychiatric symptoms. The aim of this study is to investigate whether levels of C-reactive protein (CRP) and white blood cell count (WBC) are related to positive and negative symptoms of psychotic disorders, and whether age, gender, duration of illness, smoking behavior, haloperidol equivalents, mediation use, body mass, and metabolic syndrome affect this relation.

METHODS

CRP and WBC values of 2123 patients with a psychotic disorder were related to positive and negative symptoms measured with a psychiatric interview. CRP was analyzed by survival analysis accounting for detection limit and WBC by linear mixed model analysis. In case of a significant association, the confounding factors were added to the model.

RESULTS

Both WBC and CRP were related to both positive and negative symptoms, even after correction for age, gender, smoking, use of medication and metabolic problems. Of the covariates, gender, metabolic problems, smoking and statins also showed a strong association with inflammatory markers.

CONCLUSIONS

This study in a large patient-group confirmed that inflammatory markers are related to psychotic disorders, particularly negative symptoms. Future studies could use more precise measures of inflammatory markers and measure symptomatic state at specific moments in illness progression.

Cytokines dysregulation in schizophrenia: A systematic review of psychoneuroimmune relationship

INTRODUCTION

Schizophrenia is a multifactorial psychiatric disease with complex interactions among the brain and the immune system. A psycho-immune relationship underling schizophrenia is supported by several studies and integrates a specific area of knowledge - psychoneuroimmunology.

METHODS

A systematic review was performed by 2009 Preferred Reporting Items (PRISMA) recommendations. Based on the inclusion/exclusion criteria, publications with relevant information (evaluated by the Joanna Briggs Institute Critical Appraisals tools to quality assessment) were included.

RESULTS

In this review, we considered the inflammatory activity promoted by cytokine alterations in schizophrenia aetiology, which reflects the systemic comprehension of this disease in opposition to the traditional approach focused solely on the brain. We focus on the analysis of several specific outcomes, such as proinflammatory cytokines, sample sort, laboratory techniques, diagnosis scales and results of each publication.

CONCLUSION

This systematic review confirms the existence of cytokines abnormalities in schizophrenia disease. Immune imbalances such as increased levels of some cytokines (either at protein level or at mRNA expression), cytokine mRNAs, as well as cytokine gene polymorphisms have been reported with a large support in schizophrenia. These findings provide a strong evidence of a concomitant process of inflammatory activity in schizophrenia illness course.

Accelerated aging in schizophrenia and related disorders: Future research

Several lines of evidence suggest schizophrenia is a segmental progeria, that is, some but not all aspects of accelerated aging may be present. However, the evidence has not been consistent. Problems with matching and confounding may account for some of these discrepancies. Given the etiopathophysiological heterogeneity of schizophrenia, it is possible that only a specific pathophysiological group within schizophrenia is associated with progeroid features, while others are not, or that one group is associated with a particular segment of aging features, while other progeroid features are found in another pathophysiological subgroup. In the aging research field, significant progress has been made in identifying the molecular pathways that confer aging: epigenetic changes, inflammation, proteostasis, adult stem cell function, metabolic changes, and adaptation to stress, and macromolecular damage. In addition to replication and clarification of existing kinds of evidence, examining these aging pathways would improve our understanding of progeria in schizophrenia.

Polymorphisms in immune-inflammatory response genes and the risk of deficit schizophrenia

Polymorphisms in immune-inflammatory response genes are believed to impact schizophrenia susceptibility. However, it remains unknown whether immunogenetic factors play a role in the etiology of deficit schizophrenia (D-SCZ). Therefore, we genotyped four polymorphisms in genes encoding two immune system regulatory proteins (CTLA-4 rs231775 and CD28 rs3116496), interleukin-6 (IL6 rs1800795) and transforming growth factor-β (TGFB1 rs1800470) in 513 schizophrenia patients and 374 controls. The CD28 rs3116496-CC genotype and C-allele were significantly more frequent in the whole group of patients and D-SCZ patients compared to controls. Our results indicate that the CD28 rs3116496 polymorphism might impact the risk of schizophrenia, especially D-SCZ.

Minocycline as adjunct therapy for a male patient with deficit schizophrenia

The pathophysiology of schizophrenia may involve increased production of inflammatory cytokines by activated microglia. Minocycline can inhibit activated microglia and may improve secondary negative symptoms and/or cognitive functions when used as adjuvant to antipsychotics. Effects on minocycline on primary and enduring negative symptoms in deficit schizophrenia (DS) are unknown. We present a male patient with a 3-year history of DS. He was treated for 12 weeks with risperidone at a maximal dose of 6 mg per day, then for 10 weeks with olanzapine at 20 mg per day. Symptoms did not improve, and body mass index increased from 20.41 to 22.84 kg/m². Serum levels of several inflammatory cytokines were elevated, so we prescribed minocycline as adjunct to aripiprazole for 12 weeks. Negative symptoms and cognitive impairment improved, and serum levels of inflammatory cytokines decreased. Our case suggests that clinicians may consider minocycline as adjunct therapy to antipsychotics in patients with DS with elevated serum levels of inflammatory cytokines. This highlights the need for further research into possible relationships of minocycline with negative symptoms and cognitive function in patients with DS.

Protein-C Reactive as Biomarker Predictor of Schizophrenia Phases of Illness? A Systematic Review

BACKGROUND

Schizophrenia is a complex illness in which genetic, environmental, and epigenetic components have been implicated. However, recently, psychiatric disorders appear to be related to a chronic inflammatory state, at the level of specific cerebral areas which have been found as well impaired and responsible for schizophrenia symptomatology. Hence, a role of inflammatory mediators and cytokines has been as well defined. Accordingly, the role of an acute inflammatory phase protein, the C-reactive protein (CRP) has been recently investigated.

OBJECTIVE

The objective of the present study is to evaluate how PCR may represent a biomarker in schizophrenia, i.e. correlated with illness phases and/or clinical manifestation and/or psychopathological severity.

METHODS

A systematic review was here carried out by searching the following keywords ((C-reactive protein AND ((schizophrenia) OR (psychotic disorder))) for the topics 'PCR' and 'Schizophrenia', by using MESH terms.

RESULTS

An immune dysfunction and inflammation have been described amongst schizophrenic patients. Findings reported elevated CRP levels in schizophrenia, mainly correlated with the severity of illness and during the recrudescent phase. CRP levels are higher when catatonic features, negative symptomatology and aggressiveness are associated. CRP levels appeared not to be related to suicidal behaviour and ideation.

CONCLUSION

CRP and its blood levels have been reported higher amongst schizophrenic patients, by suggesting a role of inflammation in the pathogenesis of schizophrenia. Further studies are needed to better understand if CRP may be considered a biomarker in schizophrenia.

The course of negative symptoms in first-episode schizophrenia and its predictors: A prospective two-year follow-up study

AIMS

This study aimed to investigate the course of negative symptoms and its stability over a two-year period following a first-episode schizophrenia (FES) and the possible predictors of higher severity in this symptomatology after this period.

METHODS

In this longitudinal two-year prospective follow-up study we included 268 patients with a FES, according to DSM-IV. Analysis of variance was conducted in patients who completed the full follow-up to study changes in negative symptoms over three visits. Regression analyses were conducted to show correlates and potential predictors of negative symptoms at two-year follow-up.

RESULTS

There was a significant effect for time in negative symptomatology, which was less severe at one-year follow-up after a FES and remained stable up to two years (Time 1>Time 2>Time 3); F(2,151)=20.45, p<0.001. Poorer premorbid adjustment (p=0.01) and higher negative symptoms at baseline (p<0.001) made a significant contribution to the changes in the negative symptoms severity at two-years after a FES (R²=0.21, p<0.001).

CONCLUSIONS

We found a reduction in the negative symptomatology at one-year after a FES. This change remained stable at two-year. Our results suggested that the presence of this symptomatology early in the course of the illness, together with a poorer premorbid adjustment, predict more severe negative symptoms at mid-term outcome.

Psychoneuroimmunology of mental disorders

The immune system is a key element in the organism's defence system and participates in the maintenance of homeostasis. There is growing interest in the aetiopathogenic and prognostic implications of the immune system in mental disorders, as previous studies suggest the existence of a dysregulation of the immune response and a pro-inflammatory state in patients with mental disorders, as well as an increased prevalence of neuropsychiatric symptoms in patients suffering from autoimmune diseases or receiving immune treatments. This study aims to conduct a narrative review of the scientific literature on the role of Psychoneuroimmunology in mental disorders, with special focus on diagnostic, prognostic and therapeutic issues. The development of this body of knowledge may bring in the future important advances in the vulnerability, aetiopathogenic mechanisms, diagnosis and treatment of some mental disorders.

Primary, Enduring Negative Symptoms: An Update on Research

We previously proposed that people with schizophrenia who have primary, enduring negative symptoms have a disease-deficit schizophrenia (DS)-that is separate from that affecting people with schizophrenia without these features. Additional evidence consistent with the separate disease hypothesis has accumulated in recent years. White matter changes may be widespread in deficit compared to nondeficit patients and may relate to problems in early brain migration. These 2 patient groups also appear to differ on metabolic measures prior to antipsychotic treatment. Studies of reward and defeatist beliefs provide the basis for future treatment trials. The 2 factors or groups within negative symptoms broadly defined (both primary and secondary) have also been found in DS, and recent evidence suggests these 2 symptom groups have different correlates and reflect the existence of 2 groups with in DS. Negative symptoms are found in disorders other than schizophrenia, and excess summer birth, a deficit risk factor, has been found in a non-patient group with deficit-like features. It may be useful in future research to determine whether findings in DS extend to patients with other neuropsychiatric disorders who also have negative symptoms.

Increased ratio of high sensitivity C-reactive protein to interleukin-10 as a potential peripheral biomarker of schizophrenia and aggression

BACKGROUND

Many studies have indicated that immune dysfunction might be involved in the physiopathology of schizophrenia and aggression. This study aimed to investigate the correlation between high-sensitivity C-reactive protein (hsCRP), interleukin (IL)-10 and clinical characteristics, especially aggression, and to explore the potential role of hsCRP and IL-10 as plasma biomarkers of schizophrenia.

METHODS

Forty-one patients with schizophrenia and forty healthy individuals were enrolled. Psychopathological severity and aggression were assessed using the Positive and Negative Syndrome Scale (PANSS) and Modified Overt Aggression Scale (MOAS). Plasma concentrations of hsCRP and IL-10 were assessed by enzyme-linked immunosorbent assay (ELISA).

RESULTS

(1) Higher levels of hsCRP (p<0.001), lower levels of logIL-10 (p<0.001) and higher ratio of hsCRP to IL-10 (p<0.001) were observed in the plasma of patients with schizophrenia, compared to healthy controls; (2) ROC (receiver operating characteristic) curve analysis revealed that ratio of hsCRP/IL-10 (predictive value: 0.783, p<0.01; sensitivity: 85.4%; specificity: 67.5%) was more applicable as a biomarker to distinguish patients with schizophrenia from the control group than hsCRP and IL-10 alone (predictive value: 0.718, p<0.01; 0.275, p<0.001, respectively); (3) we found positive correlations between hsCRP and the total score and verbal aggression score of MOAS (r=0.654, p<0.01; r=0.678, p<0.05), and between hsCRP/IL-10 and the total score of MOAS (r=0.636, p<0.01).

CONCLUSIONS

Our results suggest the possible function of hsCRP and IL-10 in the pathogenesis of schizophrenia and the possible value of hsCRP/IL-10 as a potential peripheral biomarker of schizophrenia. This finding also suggests a relationship between hsCRP, IL-10 and their ratio with aggression in patients with schizophrenia.

Integrity of the arcuate fasciculus in patients with schizophrenia with auditory verbal hallucinations: A DTI-tractography study

Auditory verbal hallucinations (AVH) of schizophrenia are associated with a disrupted connectivity between frontal and temporoparietal language areas. We hypothesized that this dysconnectivity is underpinned by white matter abnormalities in the left arcuate fasciculus, the main fiber bundle connecting speech production and perception areas. We therefore investigated the relationship between AVH severity and the integrity of the arcuate fasciculus measured by diffusion tensor imaging (DTI) tractography in patients with schizophrenia.

Thirty-eight patients with treatment-resistant schizophrenia were included: 26 presented with daily severe treatment-resistant AVH, 12 reported prominent negative symptoms and no AVH. Fractional anisotropy (FA) was measured along the length of the left and right anterior arcuate fasciculi and severity of AVH was assessed using P3 PANSS item.

FA values were significantly higher in the left arcuate fasciculus in patients with AVH than in no AVH patients (F_(1,35) = 3.86; p = 0.05). No difference was observed in the right arcuate fasciculus. There was a significant positive correlation between FA value in the left arcuate fasciculus and the severity of AVH (r = 0.36; p = 0.02). No correlation was observed between FA values and PANSS total score suggesting a specific relationship between AVH severity and the left arcuate fasciculus integrity.

These results support the hypothesis of a relationship between left frontotemporal connectivity and AVH in patients with schizophrenia and suggest that whilst a disruption of frontotemporal connectivity might be present to ensure the emergence of AVH, more severe anatomical alterations may prevent the occurrence of AVH in patients with schizophrenia.

•

Fractional anisotropy (FA) in the left arcuate fasciculus (AF) correlated with severity of hallucinations.

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Hallucinating patients had greater FA in the left AF than non-hallucinating patients.

•

We did not find any association between hallucinations and FA in the right AF.

Cytokines in Schizophrenia: Hope or Hype?

Although there is a cumulative evidence for the inflammation pathophysiology in schizophrenia, it has not been conclusively proven yet. One reason for this is the lack of studies that have controlled for major confounding factors such as obesity, smoking, antipsychotic use, and stress. The studies in which the major confounding factors were controlled were done in subjects in acute relapse and in treatment-resistant schizophrenia. To date, no studies have been done in stable outpatients with schizophrenia controlling for major confounding factors. Data on cerebrospinal fluid cytokines in large sample independent of confounding factors are also lacking. The efficacy signal from anti-inflammatory medications in schizophrenia has been modest. In this study, the inconsistent and nonvalidated cytokine findings independent of the confounding factors are discussed.

Cytokine profile in drug-naïve, first episode patients with psychosis

OBJECTIVE

An increasing body of evidence suggests that immunological changes may play a role in schizophrenia but the results of the studies are controversial and little is known about the presence of those changes at the onset of the disease. Our aim is to compare the levels of interleukin (IL) IL-2, IL-6, IL-10, IL-17 and transforming growth factor -β2 (TGF-β2) between drug-naïve-first episode patients with psychosis and healthy controls matched for age, sex, BMI and smoking.

METHODS

Thirty-nine drug-naïve-first episode patients with psychosis and 39 healthy individuals (control group) were enrolled in the study. Serum levels of IL-2, IL-6, IL-10, IL-17 and TGF-β2 were measured by enzyme linked immunosorbent assay (ELISA).

RESULTS

Serum IL-2 and IL-6 levels were significantly higher in the drug-naïve patients with psychosis group (p<0.022 and p<0.002 respectively) compared to healthy controls. No differences were found between the two groups in the levels of IL-10, IL-17. The levels of TGF-β2 did not differ significantly between the two groups.

CONCLUSION

The serum levels of IL-2 and IL-6 are increased in first episode drug-naïve patients with psychosis compared to healthy controls. An inflammatory response mediated by IL-2 and IL-6 may play a role in schizophrenia.

Associations of high sensitivity C-reactive protein levels in schizophrenia and comparison groups

Schizophrenia is characterized by physical (mainly metabolic and cardiovascular) comorbidity and shortened lifespan. High sensitivity C-reactive protein (hs-CRP), an inflammatory marker of hepatic origin linked to metabolic and cardiovascular diseases and mortality in the general population, has been reported to be elevated in people with schizophrenia. However, the relationship of hs-CRP to psychiatric and medical risk factors, after controlling for potentially confounding variables such as smoking, is not well established in schizophrenia. We assessed hs-CRP levels along with various demographic, psychiatric, and metabolic measures in 88 clinically stable outpatients with schizophrenia or schizoaffective disorder and 71 age epoch-matched comparison subjects with no history of a major psychiatric illness. hs-CRP levels were significantly higher in individuals with schizophrenia than in comparison subjects. Higher hs-CRP levels in the schizophrenia group were associated with female gender, more severe negative symptoms, greater medical comorbidity, and worse metabolic risk factors including BMI, fasting glucose, and hemoglobin A1c levels. hs-CRP was not related to age, race, education, smoking status, antipsychotic dosage, or cognitive impairment. Longitudinal studies are needed to investigate the relationship between hs-CRP and long-term health outcomes including metabolic syndrome, cardiovascular disease, and mortality in schizophrenia.

Adjunctive Minocycline in Clozapine-Treated Schizophrenia Patients With Persistent Symptoms

OBJECTIVE

Clozapine is the most effective antipsychotic for treatment refractory people with schizophrenia, yet many patients only partially respond. Accumulating preclinical and clinical data suggest benefits with minocycline. We tested adjunct minocycline to clozapine in a 10-week, double-blind, placebo-controlled trial. Primary outcomes tested were positive, and cognitive symptoms, while avolition, anxiety/depression, and negative symptoms were secondary outcomes.

METHODS

Schizophrenia and schizoaffective participants (n = 52) with persistent positive symptoms were randomized to receive adjunct minocycline (100 mg oral capsule twice daily; n = 29) or placebo (n = 23).

RESULTS

Brief Psychiatric Rating Scale (BPRS) psychosis factor (P = 0.098; effect size [ES], 0.39) and BPRS total score (P = 0.075; ES, 0.55) were not significant. A change in total BPRS symptoms of more than or equal to 30% was observed in 7 (25%) of 28 among minocycline and 1 (4%) of 23 among placebo participants, respectively (P = 0.044). Global cognitive function (MATRICS Consensus Cognitive Battery) did not differ, although there was a significant variation in size of treatment effects among cognitive domains (P = 0.03), with significant improvement in working memory favoring minocycline (P = 0.023; ES, 0.41). The Scale for the Assessment of Negative Symptoms total score did not differ, but significant improvement in avolition with minocycline was noted (P = 0.012; ES, 0.34). Significant improvement in the BPRS anxiety/depression factor was observed with minocycline (P = 0.028; ES, 0.49). Minocycline was well tolerated with significantly fewer headaches and constipation compared with placebo.

CONCLUSIONS

Minocycline's effect on the MATRICS Consensus Cognitive Battery composite score and positive symptoms were not statistically significant. Significant improvements with minocycline were seen in working memory, avolition, and anxiety/depressive symptoms in a chronic population with persistent symptoms. Larger studies are needed to validate these findings.

Are Negative Symptoms Dimensional or Categorical? Detection and Validation of Deficit Schizophrenia With Taxometric and Latent Variable Mixture Models

Studies have supported the validity of the deficit form of schizophrenia (ie, people with primary and enduring negative symptoms). A test of whether that group is a true taxon-that is, a distinct, discontinuous group-has yet to be conducted and the underlying structure of negative symptoms as categorical or dimensional remains undetermined. The present study examined the latent structure of negative and deficit symptoms to determine if a nonarbitrary boundary distinguishes deficit from nondeficit forms of schizophrenia (ie, whether these symptoms reflect a continuous or categorical variable). Schedule for the Deficit Syndrome ratings of 789 individuals with a psychotic disorder were submitted to taxometric and latent variable mixture analyses to test categorical vs dimensional hypotheses of negative symptoms and deficit schizophrenia. Analytic models favored a taxonic structure of negative symptoms and the validity of the deficit/nondeficit classification scheme. Taxometric classification outperformed clinician-based deficit/nondeficit classification in its association with summer birth, male sex, premorbid adjustment, neurocognition, and psychosocial functioning. Within taxon and complement classes, severity scores remained significant predictors of premorbid adjustment, neurocognition, and psychosocial functioning. Thus, although a categorical approach is validated, a hybrid categorical-dimensional conceptualization of negative symptoms also has validity for the prediction of external variables.

Inflammation in schizophrenia: A question of balance

In the past decade, there has been renewed interest in immune/inflammatory changes and their associated oxidative/nitrosative consequences as key pathophysiological mechanisms in schizophrenia and related disorders. Both brain cell components (microglia, astrocytes, and neurons) and peripheral immune cells have been implicated in inflammation and the resulting oxidative/nitrosative stress (O&NS) in schizophrenia. Furthermore, down-regulation of endogenous antioxidant and anti-inflammatory mechanisms has been identified in biological samples from patients, although the degree and progression of the inflammatory process and the nature of its self-regulatory mechanisms vary from early onset to full-blown disease. This review focuses on the interactions between inflammation and O&NS, their damaging consequences for brain cells in schizophrenia, the possible origins of inflammation and increased O&NS in the disorder, and current pharmacological strategies to deal with these processes (mainly treatments with anti-inflammatory or antioxidant drugs as add-ons to antipsychotics).