A double amino-acid change in the HLA-A peptide-binding groove is associated with response to psychotropic treatment in patients with schizophrenia

The choice of an efficient psychotropic treatment for patients with schizophrenia is a key issue to improve prognosis and quality of life and to decrease the related burden and costs. As for other complex disorders, response to drugs in schizophrenia is highly heterogeneous and the underlying molecular mechanisms of this diversity are still poorly understood. In a carefully followed-up cohort of schizophrenic patients prospectively treated with risperidone or olanzapine, we used a specially designed single-nucleotide polymorphism (SNP) array to perform a large-scale genomic analysis and identify genetic variants associated with response to psychotropic drugs. We found significant associations between response to treatment defined by the reduction in psychotic symptomatology 42 days after the beginning of treatment and SNPs located in the chromosome 6, which houses the human leukocyte antigen (HLA). After imputation of the conventional HLA class I and class II alleles, as well as the amino-acid variants, we observed a striking association between a better response to treatment and a double amino-acid variant at positions 62 and 66 of the peptide-binding groove of the HLA-A molecule. These results support the current notion that schizophrenia may have immune-inflammatory underpinnings and may contribute to pave the way for personalized treatments in schizophrenia.

A National network of schizophrenia expert centres: An innovative tool to bridge the research-practice gap

Schizophrenia is probably the most severe psychiatric disorder with much suffering for the patients and huge costs for the society. Efforts to provide optimal care by general practitioners and psychiatrists are undermined by the complexity of the disorder and difficulties in applying clinical practice guidelines and new research findings to the spectrum of cases seen in day-to-day practice. An innovative model of assessment aimed at improving global care of people with schizophrenia provided by the French national network of schizophrenia expert centres is being described. Each centre has established strong links to local health services and provides support to clinicians in delivering personalized care plans. A common set of assessment tools has been adopted by the ten centres spread over the whole French territory. A web application, e-schizo(©) has been created to record data in a common computerized medical file. This network offers systematic, comprehensive, longitudinal, and multi-dimensional assessments of cases including a medical workup and an exhaustive neuropsychological evaluation. This strategy offers an effective way to transfer knowledge and share expertise. This network is a great opportunity to improve the global patient care and is conceived as being an infrastructure for research from observational cohort to translational research.

Clinical and neuropsychological characteristics of euthymic bipolar patients having a history of severe suicide attempt

OBJECTIVE

Identifying bipolar patients at high-suicide risk is a major health issue. To improve their identification, we compared dimensional and neuropsychological profile of bipolar patients with or without history of suicide attempt, taking into account suicidal severity (i.e. admission to intensive ward).

METHOD

A total of 343 adult euthymic bipolar out-patients recruited in the French FondaMental Advanced Centres of Expertise for Bipolar Disorder were divided into three subgroups: 214 patients without history of suicide attempt, 88 patients with past history of non-severe suicide attempt and 41 patients with past history of severe suicide attempt. General intellectual functioning, speed of information processing, verbal learning and memory, verbal fluency and executive functioning were assessed.

RESULTS

Severe suicide attempters had lower affective intensity and lability than non-severe attempters. Severe suicide attempters outperformed non-severe attempters for verbal learning and non-attempters for Stroop word reading part after adjustment for study centre, age, gender, educational level, antipsychotics use, depression score, anxious and addictive comorbidities.

CONCLUSION

Neuropsychological tasks commonly used to assess bipolar patients do not seem accurate to identify suicide attempters in euthymic patients. In the future, decision-making and emotional recognition tasks should be assessed. Moreover, clinical and neuropsychological profiles should be considered together to better define suicidal risk.

Sleep in patients with remitted bipolar disorders: a meta-analysis of actigraphy studies

OBJECTIVE

Sleep dysregulation is highly prevalent in bipolar disorders (BDs), with previous actigraphic studies demonstrating sleep abnormalities during depressive, manic, and interepisode periods. We undertook a meta-analysis of published actigraphy studies to identify whether any abnormalities in the reported sleep profiles of remitted BD cases differ from controls.

METHOD

A systematic review identified independent studies that were eligible for inclusion in a random effects meta-analysis. Effect sizes for actigraphy parameters were expressed as standardized mean differences (SMD) with 95% confidence intervals (95% CI).

RESULTS

Nine of 248 identified studies met eligibility criteria. Compared with controls (N=210), remitted BD cases (N=202) showed significant differences in SMD for sleep latency (0.51 [0.28-0.73]), sleep duration (0.57 [0.30-0.84]), wake after sleep onset (WASO) (0.28 [0.06-0.50]) and sleep efficiency (-0.38 [-0.70-0.07]). Moderate heterogeneity was identified for sleep duration (I2=44%) and sleep efficiency (I2=44%). Post hoc meta-regression analyses demonstrated that larger SMD for sleep duration were identified for studies with a greater age difference between BD cases and controls (β=0.22; P=0.03) and non-significantly lower levels of residual depressive symptoms in BD cases (β=-0.13; P=0.07).

CONCLUSION

This meta-analysis of sleep in remitted bipolar disorder highlights disturbances in several sleep parameters. Future actigraphy studies should pay attention to age matching and levels of residual depressive symptoms.

Risk factors for treatment resistance in unipolar depression: a systematic review

BACKGROUND

Treatment resistant depression is a complex disorder and an important source of morbidity and mortality. Identification of risk factors of resistance may be useful to improve early recognition as well as treatment selection and prediction of outcome in patients with depression.

METHODS

The aim of this paper was to review the current status of knowledge regarding risk factors of treatment resistance in unipolar depression, in patients who failed to respond to at least two successive and adequate antidepressant treatments.

RESULTS

Systematic literature search yielded 8 publications exploring clinical and biological factors. Specific psychiatric comorbidities, psychosocial factors, clinical characteristics of the depressive episode and biological markers emerge as possible risk factor for treatment resistant depression.

LIMITATIONS

Due to the lack of objective definition and diagnostic criteria for treatment resistant depression, and the paucity of reports on risk factors, our review only summarized a small number of studies.

CONCLUSION

Future investigations of risk factors should help to improve the understanding of the mechanisms underlying resistance in mood disorders and contribute to improve their therapeutic management.

The "psychomicrobiotic": Targeting microbiota in major psychiatric disorders: A systematic review

The gut microbiota is increasingly considered as a symbiotic partner in the maintenance of good health. Metagenomic approaches could help to discover how the complex gut microbial ecosystem participates in the control of the host's brain development and function, and could be relevant for future therapeutic developments, such as probiotics, prebiotics and nutritional approaches for psychiatric disorders. Previous reviews focused on the effects of microbiota on the central nervous system in in vitro and animal studies. The aim of the present review is to synthetize the current data on the association between microbiota dysbiosis and onset and/or maintenance of major psychiatric disorders, and to explore potential therapeutic opportunities targeting microbiota dysbiosis in psychiatric patients.

Risk of myocardial infarction and stroke in bipolar disorder: a systematic review and exploratory meta-analysis

OBJECTIVE

To review the evidence on and estimate the risk of myocardial infarction and stroke in bipolar disorder.

METHOD

A systematic search using MEDLINE, EMBASE, PsycINFO, Web of Science, Scopus, Cochrane Database of Systematic Reviews, and bibliographies (1946 - May, 2013) was conducted. Case-control and cohort studies of bipolar disorder patients age 15 or older with myocardial infarction or stroke as outcomes were included. Two independent reviewers extracted data and assessed quality. Estimates of effect were summarized using random-effects meta-analysis.

RESULTS

Five cohort studies including 13 115 911 participants (27 092 bipolar) were included. Due to the use of registers, different statistical methods, and inconsistent adjustment for confounders, there was significant methodological heterogeneity among studies. The exploratory meta-analysis yielded no evidence for a significant increase in the risk of myocardial infarction: [relative risk (RR): 1.09, 95% CI 0.96-1.24, P = 0.20; I(2)  = 6%]. While there was evidence of significant study heterogeneity, the risk of stroke in bipolar disorder was significantly increased (RR 1.74, 95% CI 1.29-2.35; P = 0.0003; I(2)  = 83%).

CONCLUSION

There may be a differential risk of myocardial infarction and stroke in patients with bipolar disorder. Confidence in these pooled estimates was limited by the small number of studies, significant heterogeneity and dissimilar methodological features.

Staging systems in bipolar disorder: an International Society for Bipolar Disorders Task Force Report

OBJECTIVE

We discuss the rationale behind staging systems described specifically for bipolar disorders. Current applications, future directions and research gaps in clinical staging models for bipolar disorders are outlined.

METHOD

We reviewed the literature pertaining to bipolar disorders, focusing on the first episode onwards. We systematically searched data on staging models for bipolar disorders and allied studies that could inform the concept of staging.

RESULTS

We report on several dimensions that are relevant to staging concepts in bipolar disorder. We consider whether staging offers a refinement to current diagnoses by reviewing clinical studies of treatment and functioning and the potential utility of neurocognitive, neuroimaging and peripheral biomarkers.

CONCLUSION

Most studies to date indicate that globally defined late-stage patients have a worse overall prognosis and poorer response to standard treatment, consistent with patterns for end-stage medical disorders. We believe it is possible at this juncture to speak broadly of 'early'- and 'late'-stage bipolar disorder. Next steps require further collaborative efforts to consider the details of preillness onset and intermediary stages, and how many additional stages are optimal.

Links between sleep and body mass index in bipolar disorders: an exploratory study

STUDY OBJECTIVES

Obesity and excess bodyweight are highly prevalent in individuals with bipolar disorders (BD) and are associated with adverse consequences. Multiple factors may explain increased bodyweight in BD including side effects of psychotropic medications, and reduced physical activity. Research in the general population demonstrates that sleep disturbances may also contribute to metabolic burden. We present a cross-sectional study of the associations between body mass index (BMI) and sleep parameters in patients with BD as compared with healthy controls (HC).

METHODS

Twenty-six French outpatients with remitted BD and 29 HC with a similar BMI completed a 21-day study of sleep parameters using objective (actigraphy) and subjective (PSQI: Pittsburgh Sleep Quality Index) assessments.

RESULTS

In BD cases, but not in HC, higher BMI was significantly correlated with lower sleep efficiency (P=0.009) and with several other sleep parameters: shorter total sleep time (P=0.01), longer sleep onset latency (P=0.05), higher fragmentation index (P=0.008), higher inter-day variability (P=0.05) and higher PSQI total score (P=0.004).

CONCLUSIONS

The findings suggest a link between a high BMI and several sleep disturbances in BD, including lower sleep efficiency. Physiological mechanisms in BD cases may include an exaggeration of phenomena observed in non-clinical populations. However, larger scale studies are required to clarify the links between metabolic and sleep-wake cycle disturbances in BD.

Additive effects of childhood abuse and cannabis abuse on clinical expressions of bipolar disorders

BACKGROUND

Previous studies of bipolar disorders indicate that childhood abuse and substance abuse are associated with the disorder. Whether both influence the clinical picture, or if one is mediating the association of the other, has not previously been investigated.

METHOD

A total of 587 patients with bipolar disorders were recruited from Norway and France. A history of childhood abuse was obtained using the Childhood Trauma Questionnaire. Diagnosis and clinical variables, including substance abuse, were based on structured clinical interviews (Structured Clinical Interview for DSM-IV Axis I disorders or French version of the Diagnostic Interview for Genetic Studies).

RESULTS

Cannabis abuse was significantly associated with childhood abuse, specifically emotional and sexual abuse (χ 2 = 8.63, p = 0.003 and χ 2 = 7.55, p = 0.006, respectively). Cannabis abuse was significantly associated with earlier onset of the illness (z = -4.17, p < 0.001), lifetime history of at least one suicide attempt (χ 2 = 11.16, p = 0.001) and a trend for rapid cycling (χ 2 = 3.45, p = 0.06). Alcohol dependence was associated with suicide attempt (χ 2 = 10.28, p = 0.001), but not with age at onset or rapid cycling. After correcting for possible confounders and multiple testing, a trend was observed for an interaction between cannabis abuse and childhood abuse and suicide attempt (logistic regression: r 2 = 0.06, p = 0.039). Significant additive effects were also observed between cannabis abuse and childhood abuse on earlier age at onset (p < 0.001), increased rapid cycling and suicide attempt (logistic regression: r 2 = 0.03-0.04, p < 0.001). No mediation effects were observed; childhood abuse and cannabis abuse were independently associated with the disorder.

CONCLUSIONS

Our study is the first to demonstrate significant additive effects, but no mediation effects, between childhood abuse and cannabis abuse on increased clinical expressions of bipolar disorders.

Allelic differences between Europeans and Chinese for CREB1 SNPs and their implications in gene expression regulation, hippocampal structure and function, and bipolar disorder susceptibility

Bipolar disorder (BD) is a polygenic disorder that shares substantial genetic risk factors with major depressive disorder (MDD). Genetic analyses have reported numerous BD susceptibility genes, while some variants, such as single-nucleotide polymorphisms (SNPs) in CACNA1C have been successfully replicated, many others have not and subsequently their effects on the intermediate phenotypes cannot be verified. Here, we studied the MDD-related gene CREB1 in a set of independent BD sample groups of European ancestry (a total of 64,888 subjects) and identified multiple SNPs significantly associated with BD (the most significant being SNP rs6785[A], P=6.32 × 10(-5), odds ratio (OR)=1.090). Risk SNPs were then subjected to further analyses in healthy Europeans for intermediate phenotypes of BD, including hippocampal volume, hippocampal function and cognitive performance. Our results showed that the risk SNPs were significantly associated with hippocampal volume and hippocampal function, with the risk alleles showing a decreased hippocampal volume and diminished activation of the left hippocampus, adding further evidence for their involvement in BD susceptibility. We also found the risk SNPs were strongly associated with CREB1 expression in lymphoblastoid cells (P<0.005) and the prefrontal cortex (P<1.0 × 10(-6)). Remarkably, population genetic analysis indicated that CREB1 displayed striking differences in allele frequencies between continental populations, and the risk alleles were completely absent in East Asian populations. We demonstrated that the regional prevalence of the CREB1 risk alleles in Europeans is likely caused by genetic hitchhiking due to natural selection acting on a nearby gene. Our results suggest that differential population histories due to natural selection on regional populations may lead to genetic heterogeneity of susceptibility to complex diseases, such as BD, and explain inconsistencies in detecting the genetic markers of these diseases among different ethnic populations.

Effectiveness and tolerance of anti-inflammatory drugs' add-on therapy in major mental disorders: a systematic qualitative review

OBJECTIVE

To provide a systematic review of the literature regarding the efficacy of anti-inflammatory drugs in three major mental disorders [major depressive disorder (MDD), schizophrenia and bipolar disorders].

METHOD

Four databases were explored, without any year or language restrictions. The baseline search paradigm was limited to open-labelled clinical and randomized controlled trials (RCTs).

RESULTS

Four major classes of anti-inflammatory drugs were identified, namely polyunsaturated fatty acids (PUFAs), cyclooxygenase (COX) inhibitors, anti-TNFalpha and minocycline. Effectiveness and benefit/risk ratio of each class in MDD, bipolar disorders and schizophrenia was detailed when data were available. Several meta-analyses indicated effectiveness of PUFAs in MDD with a good tolerance profile. One meta-analysis indicated that COX-2 specific inhibitors showed effectiveness in schizophrenia. Anti-TNFalpha showed important effectiveness in resistant MDD with blood inflammatory abnormalities. Minocycline showed effectiveness in schizophrenia.

CONCLUSION

Polyunsaturated fatty acids seem to have the best benefit/risk ratio profile but proved their effectiveness only in MDD. A number of anti-inflammatory drugs are available as adjunct treatment for treatment-resistant patients with MDD, schizophrenia and bipolar disorder. If used with caution regarding their possible side-effects, they may be reasonable therapeutic alternatives for resistant symptomatology.

Affect intensity measure in bipolar disorders: a multidimensional approach

BACKGROUND

Emotional dysregulation, characterized by high levels of both arousal and intensity of emotional responses, is a core feature of bipolar disorders (BDs). In non-clinical populations, the 40-item Affect Intensity Measure (AIM) can be used to assess the different dimensions of emotional reactivity.

METHODS

We analyzed the factor structure of the AIM in a sample of 310 euthymic patients with BD using Principal Component Analysis and examined associations between AIM sub-scale scores and demographic and illness characteristics.

RESULTS

The French translation of the AIM demonstrated good reliability. A four-factor solution similar to that reported in non-clinical samples (Positive Affectivity, Unpeacefulness [lack of Serenity], Negative Reactivity, Negative Intensity), explained 47% of the total variance. Age and gender were associated with Unpeacefulness and Negative reactivity respectively. 'Unpeacefulness' was also positively associated with psychotic symptoms at onset (p=0.0006), but negatively associated with co-morbid substance misuse (p=0.008). Negative Intensity was positively associated with social phobia (p=0.0005).

LIMITATIONS

We cannot definitively exclude a lack of statistical power to classify all AIM items. Euthymia was carefully defined, but a degree of 'contamination' of the self-reported levels of emotion reactivity may occur because of subsyndromal BD symptoms. It was not feasible to control for the possible impact of on-going treatments.

CONCLUSIONS

The AIM scale appears to be a useful measure of emotional reactivity and intensity in a clinical sample of patients with BD, suggesting it can be used in addition to other markers of BD characteristics and sub-types.

Cytomegalovirus seropositivity and serointensity are associated with hippocampal volume and verbal memory in schizophrenia and bipolar disorder

INTRODUCTION

Cytomegalovirus (CMV) is a member of the herpesviridae family that has a limbic and temporal gray matter tropism. It is usually latent in humans but has been associated with schizophrenia, bipolar disorder and cognitive deficits in some populations. Hippocampal decreased volume and dysfunction play a critical role in these cognitive deficits. We hypothesized that CMV seropositivity and serointensity would be associated with hippocampal volume and cognitive functioning in patients with schizophrenia or bipolar disorder.

METHODS

102 healthy controls, 118 patients with bipolar disorder and 69 patients with schizophrenia performed the California Verbal Learning Test (CVLT) and had blood samples drawn to assess CMV IgG levels. A subgroup of 52 healthy controls, 31 patients with bipolar disorder and 27 patients with schizophrenia underwent T1 MRI for hippocampal volumetry. We analyzed the association between CMV serointensity and seropositivity with hippocampal volume. We also explored the correlation between CMV serointensity and seropositivity and CVLT scores.

RESULTS

In both patient groups but not in controls, higher CMV serointensity was significantly associated with smaller right hippocampal volume. Further, in the group of patients with schizophrenia but not bipolar disorder, CMV serointensity was negatively correlated with CVLT scores.

CONCLUSION

CMV IgG titers are associated with decreased hippocampal volume and poorer episodic verbal memory in patients with schizophrenia or bipolar disorder. The mechanism of this association warrants further exploration.