Increased cardiometabolic dysfunction in first-degree relatives of patients with psychotic disorders

Genetic predisposition and antipsychotic treatment effect on metabolic syndrome in schizophrenia: a ten-year follow-up study using the Estonian Biobank

Background

Schizophrenia (SCZ) patients exhibit 30% higher prevalence of metabolic syndrome (MetS) compared to the general population with its suboptimal management contributing to increased mortality. Large-scale studies providing real-world evidence of the underlying causes remain limited.

Methods

To address this gap, we used real-world health data from the Estonian Biobank, spanning a median follow-up of ten years, to investigate the impact of genetic predisposition and antipsychotic treatment on the development of MetS in SCZ patients. Specifically, we set out to characterize antipsychotic treatment patterns, genetic predisposition of MetS traits, MetS prognosis, and body mass index (BMI) trajectories, comparing SCZ cases (n = 677) to age- and sex-matched controls (n = 2708).

Findings

SCZ cases exhibited higher genetic predisposition to SCZ (OR = 1.75, 95% CI 1.58-1.94), but lower polygenic burden for increased BMI (OR = 0.88, 95% CI 0.88-0.96) and C-reactive protein (OR = 0.88, 95% CI 0.81-0.97) compared to controls. While SCZ cases showed worse prognosis of MetS (HR 1.95, 95% CI 1.54-2.46), higher antipsychotic adherence within the first treatment year was associated with reduced long-term MetS incidence. Linear mixed modelling, incorporating multiple BMI timepoints, underscored the significant contribution of both, antipsychotic medication, and genetic predisposition to higher BMI, driving the substantially upward trajectory of BMI in SCZ cases.

Interpretation

These findings contribute to refining clinical risk prediction and prevention strategies for MetS among SCZ patients and emphasize the significance of incorporating genetic information, long-term patient tracking, and employing diverse perspectives when analyzing real-world health data.

Funding

EU Horizon 2020, Swedish Research Council, Estonian Research Council, Estonian Ministry of Education and Research, University of Tartu.

Multimorbidity and the Etiology of Schizophrenia

PURPOSE OF REVIEW

A global study of multimorbidity in schizophrenia, especially of the association with physical conditions, might offer much needed etiological insights.

RECENT FINDINGS

Our review suggests that life-style factors and medication related to schizophrenia are only part of the explanation of the increase in risk for cardiovascular, metabolic, pulmonary disorders, and some cancers. Positive associations with autoimmune disorders (with the exception of rheumatoid arthritis) and epilepsy are promising avenues of research but to date have not been fully exploited. The same holds for the negative comorbidity seen for rheumatoid arthritis and some cancers (e.g., prostate). As a whole, our review suggests that most of the explored conditions have a different prevalence in schizophrenia than in the general population. Several hypotheses emerged from this review such as the role of immune and genetic factors, of sex hormones, and of more general variability factors.

Characterizing the Shared Genetic Underpinnings of Schizophrenia and Cardiovascular Disease Risk Factors

OBJECTIVE

Schizophrenia is associated with increased risk of cardiovascular disease (CVD), although there is variation in risk among individuals. There are indications of shared genetic etiology between schizophrenia and CVD, but the nature of the overlap remains unclear. The aim of this study was to fill this gap in knowledge.

METHODS

Overlapping genetic architectures between schizophrenia and CVD risk factors were assessed by analyzing recent genome-wide association study (GWAS) results. The bivariate causal mixture model (MiXeR) was applied to estimate the number of shared variants and the conjunctional false discovery rate (conjFDR) approach was used to pinpoint specific shared loci.

RESULTS

Extensive genetic overlap was found between schizophrenia and CVD risk factors, particularly smoking initiation (N=8.6K variants) and body mass index (BMI) (N=8.1K variants). Several specific shared loci were detected between schizophrenia and BMI (N=304), waist-to-hip ratio (N=193), smoking initiation (N=293), systolic (N=294) and diastolic (N=259) blood pressure, type 2 diabetes (N=147), lipids (N=471), and coronary artery disease (N=35). The schizophrenia risk loci shared with smoking initiation had mainly concordant effect directions, and the risk loci shared with BMI had mainly opposite effect directions. The overlapping loci with lipids, blood pressure, waist-to-hip ratio, type 2 diabetes, and coronary artery disease had mixed effect directions. Functional analyses implicated mapped genes that are expressed in brain tissue and immune cells.

CONCLUSIONS

These findings indicate a genetic propensity to smoking and a reduced genetic risk of obesity among individuals with schizophrenia. The bidirectional effects of the shared loci with the other CVD risk factors may imply differences in genetic liability to CVD across schizophrenia subgroups, possibly underlying the variation in CVD comorbidity.

Insulin resistance and lipid levels in the middle-aged offspring of parents with severe mental illness

BACKGROUND

Type 2 diabetes and dyslipidemias co-occur frequently with severe mental illnesses (SMI). However, less is known about serum insulin and lipid levels and prevalence of Insulin Resistance (IR) in offspring with familial risk for SMI.

METHOD

The Northern Finland Birth Cohort 1966 consists of 12,068 mothers, 11,068 fathers, and 12,231 children from the two northernmost provinces in Finland. At age 46 they participated in clinical examination including measurements of glucose, lipids, and IR and answered a questionnaire including information about their nutrition and physical activity. The information on parental SMI was obtained from the Hospital Discharge Register. Parents with SMI were those who had been treated in hospital for any psychiatric disorder during 1969-1982 (ICD-8 codes 290-315). The final study group included 334 (7.3 %) offspring who had a parent with SMI and 4249 (92.7 %) offspring in the comparison group.

RESULTS

We did not find increased risk for disturbances in lipid levels, insulin levels, or IR levels between the study group (offspring of either parent with SMI) compared with the comparison group. All offspring, especially female offspring of either parent with SMI, had an increased risk for higher glucose levels and waist circumference. The results remained the same after excluding offspring with SMI.

CONCLUSION

Our findings suggest that offspring of parents with SMI, especially female offspring, have partly increased risk for disturbances in cardiometabolic risk factors. Disturbances in glucose metabolism may have an effect via familial risk of severe mental illness.

Associations of common genetic risk variants of the muscarinic acetylcholine receptor M2 with cardiac autonomic dysfunction in patients with schizophrenia

OBJECTIVES

Decreased vagal modulation, which has consistently been observed in schizophrenic patients, might contribute to increased cardiac mortality in schizophrenia. Previously, associations between CHRM2 (Cholinergic Receptor Muscarinic 2) and cardiac autonomic features have been reported. Here, we tested for possible associations between these polymorphisms and heart rate variability in patients with schizophrenia.

METHODS

A total of three single nucleotide polymorphisms (SNPs) in CHRM2 (rs73158705 A>G, rs8191992 T>A and rs2350782 T>C) that achieved significance (p < 5 * 10^-8) in genome-wide association studies for cardiac autonomic features were genotyped in 88 drug-naïve patients, 61 patients receiving antipsychotic medication and 144 healthy controls. Genotypes were analysed for associations with parameters of heart rate variability and complexity, in each diagnostic group.

RESULTS

We observed a significantly altered heart rate variability in unmedicated patients with identified genetic risk status in rs73158705 A>G, rs8191992 T>A and rs2350782 T>C as compared to genotype non-risk status. In patients receiving antipsychotic medication and healthy controls, these associations were not observed.

DISCUSSION

We report novel candidate genetic associations with cardiac autonomic dysfunction in schizophrenia, but larger cohorts are required for replication.

Physical health status in first-degree relatives of patients with bipolar disorder, a systematic review

OBJECTIVE

This systematic literature search aimed to investigate the physical health status of first-degree relatives to patients with bipolar disorder. There is abundant evidence for familial aggregation of both bipolar disorders, cardiovascular and autoimmune diseases. However, a review gathering data on the physical health status in first-degree relatives to patients with bipolar disorder is missing. We hypothesized that first-degree relatives of bipolar probands would express higher rates of physical diseases and somatic morbidity.

METHOD

We conducted a systematic literature search in three different databases PubMed, Embase and PsychInfo. The search identified 10 studies comparing 24,277 unaffected first-degree relatives with 318.933 controls persons.

RESULTS

Seven out of 10 studies showed that first-degree relatives had statistically significantly higher rates of one or more physical diseases or increased morbidity, including cardiovascular diseases, infections, autoimmune thyroiditis, pernicious anaemia, and higher mortality compared with control persons.

CONCLUSION

Findings from this systematic literature review did not unambiguously confirm a possible link between bipolar disorder and overall increased risk of physical diseases in first-degree relatives of probands with bipolar disorder. However, these results could suggest that first-degree relatives of probands with bipolar disorder could have a predisposition to poorer physical health than the general population and that this aspect warrants further investigation.

Familial aggregation and shared genetic loading for major psychiatric disorders and type 2 diabetes

AIMS/HYPOTHESIS

Psychiatric disorders, such as schizophrenia (SCZ), major depressive disorder (MDD) and bipolar disorder (BPD), are highly comorbid with type 2 diabetes. However, the mechanisms underlying such comorbidity are understudied. This study explored the familial aggregation of common psychiatric disorders and type 2 diabetes by testing family history association, and investigated the shared genetic loading between them by testing the polygenic risk score (PRS) association.

METHODS

A total of 105,184 participants were recruited from the Taiwan Biobank, and genome-wide genotyping data were available for 95,238 participants. The Psychiatric Genomics Consortium-derived PRS for SCZ, MDD and BPD was calculated. Logistic regression was used to estimate the OR with CIs between a family history of SCZ/MDD/BPD and a family history of type 2 diabetes, and between the PRS and the risk of type 2 diabetes.

RESULTS

A family history of type 2 diabetes was associated with a family history of SCZ (OR 1.23, 95% CI 1.08, 1.40), MDD (OR 1.19, 95% CI 1.13, 1.26) and BPD (OR 1.26, 95% CI 1.15, 1.39). Compared with paternal type 2 diabetes, maternal type 2 diabetes was associated with a higher risk of a family history of SCZ. SCZ PRS was negatively associated with type 2 diabetes in women (OR 0.92, 95% CI 0.88, 0.97), but not in men; the effect of SCZ PRS reduced after adjusting for BMI. MDD PRS was positively associated with type 2 diabetes (OR 1.04, 95% CI 1.00, 1.07); the effect of MDD PRS reduced after adjusting for BMI or smoking. BPD PRS was not associated with type 2 diabetes.

CONCLUSIONS/INTERPRETATION

The comorbidity of type 2 diabetes with psychiatric disorders may be explained by shared familial factors. The shared polygenic loading between MDD and type 2 diabetes implies not only pleiotropy but also a shared genetic aetiology for the mechanism behind the comorbidity. The negative correlation between polygenic loading for SCZ and type 2 diabetes implies the role of environmental factors.

Cardiometabolic Disorders in the Offspring of Parents With Severe Mental Illness

OBJECTIVE

The elevated prevalence of cardiometabolic disorders is consistently reported in patients with severe mental illness (SMI). We explored the association between parental SMI and offspring cardiometabolic morbidity. Our hypothesis was that offspring of people with SMI have increased morbidity risk.

METHOD

The Northern Finland Birth Cohort 1966 is a study of offspring whose date of birth was expected in 1966. The follow-up lasted until 2015 (49 years). The final study sample included 11,175 children. We used parental SMI as the exposure in the study. The following cardiometabolic disorders were used as outcome measures: diabetes mellitus, hypertension, hyperlipidemia, coronary artery disease, obesity, and cerebrovascular disorders.

RESULTS

There were 139 (14.7%; hazard ratios [HR] = 1.63; 95% confidence interval [CI] = 1.36-1.94) children of parents with SMI who developed cardiometabolic disorder during follow-up and 957 (9.4%) in the comparison cohort. Statistically significant HRs were found in males (HR = 1.95; 95% CI =1.56-2.44), but not in females (HR = 1.29; 95% CI = 0.96-1.73).

CONCLUSIONS

Having a cardiometabolic disorder was associated with male offspring of parents with SMI. Our findings suggest that there is an elevated risk of coronary artery disease, hyperlipidemia, obesity, and hypertension in the male offspring of parents with SMI. Our results suggest that the somatic health of offspring of parents with SMI should also be considered in addition to their mental health in clinical practice.

[Schizophrenia and cardiometabolic disorders]

The aim of this review is to analyze the basic biological mechanisms of comorbidity of schizophrenia and metabolic, cardiovascular diseases, which are not directly associated with external risk factors. The study of the general pathophysiological mechanisms of schizophrenia and metabolic disorders can provide a significant basis not only for the fundamentally novel therapeutic, preventive and diagnostic measures, but also for a better understanding of the etiopathogenesis of these diseases. It seems likely that schizophrenia represents a heterogeneous group with a varying genetic basis for both mental symptoms and neuroendocrine, inflammatory processes that form concomitant somatic disorders. Thus, the new integrated approaches to the study of this problem with the latest methods of genetic and molecular research are relevant.

A nation-wide population-based longitudinal study mapping physical diseases in patients with bipolar disorder and their siblings

BACKGROUND

Patients with bipolar disorder may have increased risk of physical diseases due to genetic and environmental factors, but no study has systematically mapped all physical comorbidities in such subjects. The aim was to map rates of all physical diseases among patients and siblings to patients with bipolar disorder.

METHODS

We used Danish nation-wide population-based longitudinal register linkage to identify 19.955 patients with bipolar disorder, their 13.923 siblings and 20 sex, age and calendar matched control individuals from the general population. Follow-up was from 1995 to 2017.

RESULTS

Bipolar disorder was associated with increased rates of all physical disease categories compared with rates for control individuals, except for cancer. Further, bipolar disorder was associated with increased rates of separate disorders including ischemic heart disease, diabetes, dementia, hypertension, hypercholesterolemia and hyperlipidemia, hypothyroidism and infections. In contrast, siblings to patients with bipolar disorder who were unaffected by bipolar disorder had increased rates of certain disorders, only, comprising infectious and parasitic diseases, and diseases of the nervous system, digestive system and genitourinary system.

LIMITATIONS

Underdetection of physical disorders is likely because data are not available for persons who do not seek help for their disorders.

CONCLUSIONS

Bipolar disorder was associated with increased rates of all physical diseases categories, except cancer, and with separate disorders, likely involving inflammatory components in the pathogenesis. In contrast, unaffected siblings to patients with bipolar disorder had increased rates of certain disorders, only.

Cardiovascular disease in patients with severe mental illness

Individuals diagnosed with schizophrenia or bipolar disorder have a life expectancy 15-20 years shorter than that in the general population. The rate of unnatural deaths, such as suicide and accidents, is high for these patients. Despite this increased proportion of unnatural deaths, physical conditions account for approximately 70% of deaths in patients with either schizophrenia or bipolar disorder, with cardiovascular disease contributing 17.4% and 22.0% to the reduction in overall life expectancy in men and women, respectively. Risk factors for cardiovascular disease, such as smoking, unhealthy diet and lack of exercise, are common in these patients, and lifestyle interventions have been shown to have small effects. Pharmacological interventions to reduce risk factors for cardiovascular disease have been proven to be effective. Treatment with antipsychotic drugs is associated with reduced mortality but also with an increased risk of weight gain, dyslipidaemia and diabetes mellitus. These patients have higher risks of both myocardial infarction and stroke but a lower risk of undergoing interventional procedures compared with the general population. Data indicate a negative attitude from clinicians working outside the mental health fields towards patients with severe mental illness. Education might be a possible method to decrease the negative attitudes towards these patients, thereby improving their rates of diagnosis and treatment.

Meta-analysis of comorbid diabetes and family history of diabetes in non-affective psychosis

OBJECTIVE

Schizophrenia and other non-affective psychoses (NAP) are associated with an increased prevalence of both type 2 diabetes (DM2) as well as a family history of DM2. We performed a systematic review and meta-analysis of the association between comorbid DM2 and a family history of DM2 in patients with NAP.

METHOD

We searched major electronic databases from inception until August 2018 for studies of comorbid DM2 in patients with non-affective psychosis and family history of DM2 status. Random effects meta-analysis calculating odds ratios (ORs) and 95% confidence intervals (CI) and meta-regression analyses were performed.

RESULTS

Ten studies met the inclusion criteria. Across these studies, there were 804 patients with non-affective psychosis and comorbid DM2, and 2976 patients with non-affective psychosis without this comorbidity. A family history of DM2 was associated with an over four-fold increased odds of comorbid DM2 in patients with NAP (OR = 4.3, 95% CI 2.9-6.4, p<0.001). In; meta-regression analyses older age, but not sex, BMI, geographic region, study quality, or year; of publication moderated the association between comorbid DM2 and family history of DM2.

CONCLUSION

We found that a family history of DM2 was associated with an over four-fold increased odds of comorbid DM2 in patients with NAP. This association may be due to shared environmental or genetic risk factors, or gene-environment interactions. Given the increased risk of incident diabetes with antipsychotic treatment, screening for a family history of DM2 is germane to the clinical care of patients with NAP.

Mortality by diseases and medical conditions in the offspring of parents with severe mental illness

PURPOSE

The lifespan of people with severe mental illness (SMI) is shorter compared to the general population. There might be common familial pathway leading to a high co-occurrence of somatic disorders and SMI. To study this we explored the long-term mortality for natural causes in the offspring of people with SMI.

METHODS

Participants were members of the Northern Finland Birth Cohort 1966 (NFBC1966; N = 11,325). The data on cause of deaths of the members were obtained from the Population Register Center until year 2015. The data on hospital-treated psychiatric disorders of parents were obtained from nationwide Care Register for Health Care. Cumulative incidences by age were calculated in the NFBC1966 members having a parent with SMI and those who did not have. We were able to take into account multiple confounders.

RESULTS

Of the total sample of 11,325 offspring, 853 (7.4%) died during the follow-up period, 74 (8.7%) from the study cohort and 779 (91.3%) from the comparison group. These numbers included 160 stillborn children. There were 557 cases of deaths from diseases and medical conditions and 296 deaths from external causes. The adjusted risk ratio for offspring of mothers with SMI was 1.08 (0.72-1.64), and for offspring of fathers with SMI 0.58 (0.36-0.93).

CONCLUSIONS

This was the first long-term follow-up study (up to age 49) of all-cause mortality in offspring of parents with SMI. Our findings were contrary to expectations. Offspring of parents with SMI had no increased risk for dying. In fact, the risk for dying in the group of offspring of fathers with SMI was lower than in the comparison group. This study does not support the assumption of common familial pathway leading to a high co-occurrence of somatic disorders and SMI.

Evidence-based guidelines for the pharmacological treatment of schizophrenia: Updated recommendations from the British Association for Psychopharmacology

These updated guidelines from the British Association for Psychopharmacology replace the original version published in 2011. They address the scope and targets of pharmacological treatment for schizophrenia. A consensus meeting was held in 2017, involving experts in schizophrenia and its treatment. They were asked to review key areas and consider the strength of the evidence on the risk-benefit balance of pharmacological interventions and the clinical implications, with an emphasis on meta-analyses, systematic reviews and randomised controlled trials where available, plus updates on current clinical practice. The guidelines cover the pharmacological management and treatment of schizophrenia across the various stages of the illness, including first-episode, relapse prevention, and illness that has proved refractory to standard treatment. It is hoped that the practice recommendations presented will support clinical decision making for practitioners, serve as a source of information for patients and carers, and inform quality improvement.

Impaired insulin signaling in unaffected siblings and patients with first-episode psychosis

Patients with psychotic disorders are at high risk for type 2 diabetes mellitus, and there is increasing evidence that patients display glucose metabolism abnormalities before significant antipsychotic medication exposure. In the present study, we examined insulin action by quantifying insulin sensitivity in first-episode psychosis (FEP) patients and unaffected siblings, compared to healthy individuals, using a physiological-based model and comprehensive assessment battery. Twenty-two unaffected siblings, 18 FEP patients, and 15 healthy unrelated controls were evaluated using a 2-h oral glucose tolerance test (OGTT), with 7 samples of plasma glucose and serum insulin concentration measurements. Insulin sensitivity was quantified using the oral minimal model method. Lipid, leptin, free fatty acids, and inflammatory marker levels were also measured. Anthropometric, nutrient, and activity assessments were conducted; total body composition and fat distribution were determined using whole-body dual-energy X-ray absorptiometry. Insulin sensitivity significantly differed among groups (F = 6.01 and 0.004), with patients and siblings showing lower insulin sensitivity, compared to controls (P = 0.006 and 0.002, respectively). Body mass index, visceral adipose tissue area (cm²), lipids, leptin, free fatty acids, inflammatory markers, and activity ratings were not significantly different among groups. There was a significant difference in nutrient intake with lower total kilocalories/kilogram body weight in patients, compared to siblings and controls. Overall, the findings suggest that familial abnormal glucose metabolism or a primary insulin signaling pathway abnormality is related to risk for psychosis, independent of disease expression and treatment effects. Future studies should examine underlying biological mechanisms of insulin signaling abnormalities in psychotic disorders.

Risk of cardiometabolic diseases among siblings of patients with bipolar disorder

BACKGROUND

Cardiometabolic diseases are suggested to be associated with bipolar disorder. However, the risk of metabolic disorders in unaffected siblings of patients with bipolar disorder remains unclear.

METHODS

From the Taiwan National Health Insurance Research Database, 7,225 unaffected siblings of bipolar probands and 28,900 age-/sex-/income-/residence-matched control individuals were included and followed until the end of 2011. Individuals who developed metabolic disorders during the follow-up period were identified.

RESULTS

The unaffected siblings of bipolar probands had a higher prevalence of dyslipidemia (5.4% vs. 4.5%, p = 0.001), younger age at diagnosis of type 2 diabetes mellitus (34.81 vs. 37.22, p = 0.024), and higher prevalence of any stroke (1.5% vs. 1.1%, p = 0.007) than the controls. Moreover, only male siblings of bipolar probands had an increased risk of dyslipidemia (odds ratio [OR]: 1.28, 95% confidence interval [CI]: 1.10-1.48) and higher rates of any stroke (OR: 1.38, 95% CI: 1.02-1.85) and ischemic stroke (OR: 2.43, 95% CI: 1.60-3.70) during the follow-up compared with the controls.

DISCUSSION

Unaffected siblings of bipolar patients, particularly brothers, had a higher prevalence of dyslipidemia and ischemic stroke compared with the controls. The result suggests the familial association between cardiometabolic diseases and bipolar disorder. Further research may be necessary to identify this shared etiology between the disorders.

Brain insulin action in schizophrenia: Something borrowed and something new

Insulin signaling in the central nervous system is at the intersection of brain and body interactions, and represents a fundamental link between metabolic and cognitive disorders. Abnormalities in brain insulin action could underlie the development of comorbid schizophrenia and type 2 diabetes. Among its functions, central nervous system insulin is involved in regulation of striatal dopamine levels, peripheral glucose homeostasis, and feeding regulation. In this review, we discuss the role and importance of central nervous system insulin in schizophrenia and diabetes pathogenesis from a historical and mechanistic perspective. We describe central nervous system insulin sites and pathways of action, with special emphasis on glucose metabolism, cognitive functioning, inflammation, and food preferences. Finally, we suggest possible mechanisms that may explain the actions of central nervous system insulin in relation to schizophrenia and diabetes, focusing on glutamate and dopamine signaling, intracellular signal transduction pathways, and brain energetics. Understanding the interplay between central nervous system insulin and schizophrenia is essential to disentangling this comorbid relationship and may provide novel treatment approaches for both neuropsychiatric and metabolic dysfunction. This article is part of the issue entitled 'Special Issue on Antipsychotics'.

Elevated Familial Cardiovascular Burden Among Adolescents With Familial Bipolar Disorder

Background: Bipolar disorder (BD) is one of the most heritable medical conditions, and certain phenotypic characteristics are especially familial in BD. BD is also strongly associated with elevated and premature cardiovascular disease (CVD) morbidity and mortality. Thus, far, little is known regarding the familiality of cardiovascular risk in BD. We therefore examined the extent of CVD-related conditions among relatives of: adolescents with BD with a family history of BD (familial BD), adolescents with BD without a family history of BD (non-familial BD) and healthy controls (HC). Materials and Methods: The sample included 372 adolescents; 75 with familial BD, 96 with non-familial BD, and 201 HC. Parents of the adolescents completed the CARDIA Family Medical History interview regarding the adolescents' first- and second- degree adult relatives. We computed a "cardiovascular risk score" (CRS) for each relative, based on the sum of the presence of diabetes, hypertension, obesity, dyslipidemia, stroke, angina, and myocardial infarction (range 0-7). Primary analyses examined for group differences in mean overall CRS scores among first and second- degree relatives combined, controlling for age, sex, and race. Secondary analyses examined first- and second-degree relatives separately, controlling for age, sex, and race. Results: There were significant between-group differences in CRS in first- and second- degree relatives combined, following the hypothesized ordering: CRS was highest among adolescents with familial BD (1.14 ± 0.78), intermediate among adolescents with non-familial BD (0.92 ± 0.79) and lowest in HC (0.76 ± 0.79; F = 6.23, df = 2, p = 0.002, η p 2 = 0.03). There was a significant pairwise difference between adolescents with familial BD and HC (p = 0.002, Cohen's d = 0.49). A similar pattern of between-group differences was identified when first-degree and second-degree relatives were examined separately. Limitations: familial cardiovascular burden was determined based on parent interview, not evaluated directly. Conclusions: Adolescents with BD with a family history of BD have elevated rates of CVD-related conditions among their relatives. This may be related to genetic overlap between BD and CVD-related conditions, shared environmental factors that contribute to both BD and CVD-related conditions, or a combination of these factors. More research is warranted to better understand the interaction between familial risk for BD and CVD, and to address this risk using family-wide preventive approaches.

Expression of dopamine signaling genes in the post-mortem brain of individuals with mental illnesses is moderated by body mass index and mediated by insulin signaling genes

Preclinical studies implicate insulin signaling as a modulator of dopamine transmission, but human data is currently limited. We hypothesize that changes in the expression of insulin receptor-related genes in the post-mortem brain tissue of patients with mood and psychotic disorders mediate the expression of dopamine regulation-related genes. From a database containing microarray data from the post-mortem dorsolateral prefrontal cortex (dlPFC) (healthy controls [HC]: n = 209; patients: n = 321) and hippocampus (HC: n = 180; patients: n = 196), we conducted a hypothesis-driven analysis through the a priori selection of 12 dopamine- and 3 insulin-related genes. Mediation and moderated mediation models, accounting for the role of body mass index (BMI), were used. In the dlPFC, expressions of insulin receptor- and dopamine regulation-related genes were moderated by BMI, with significantly lower expression in high BMI patients. In the hippocampus, there were significantly lower expressions of these genes, which were not moderated by BMI. Illnesses by BMI effects on expression of dopamine genes were fully mediated by expression of insulin receptor gene (INSR). Analysis of conditional indirect effects showed interactions between INSR and BMI, indicating significantly stronger indirect effects at higher BMI values. In the hippocampus we observed that expression of insulin receptor substrate 1 and 2 fully mediated the effects of illnesses on expression of dopamine genes. In conclusion, differential expression of dopamine-related genes was related to altered expression of insulin signaling genes. BMI had region-specific effects, supporting the hypothesis that metabolic systems are critical mediators of dopaminergic function.

Comorbidity of chronic somatic diseases in patients with psychotic disorders and their influence on 4-year outcomes of integrated care treatment (ACCESS II study)

BACKGROUND

People with psychotic disorders fulfilling criteria of a severe and persistent mental illness (SPMI) display a high risk of somatic comorbidity (SC).

METHODS

ACCESS II is a prospective, long-term study examining the effectiveness of Integrated Care for people with psychotic disorders fulfilling SPMI criteria. Chronic comorbid somatic disorders were systematically assessed according to ICD-10-GM criteria. Patients treated for ≥4years in ACCESS were categorized as early psychosis (treatment: ≤2years) or non-early psychosis (treatment: >2years) patients.

RESULTS

Of 187 patients treated in ACCESS for ≥4years (mean age=41.8years, males=44.4%), 145 (77.5%) had SC, (mean=2.1±2.1). Overall, 55 different diseases from 15 different ICD-10-GM disease areas were identified. Prevalence of ≥1 SC (p=0.09) and specific types of SC (p=0.08-1.00) did not differ between early and non-early psychosis patients, but non-early psychosis patients had a higher mean number of SC (2.3±2.2 vs. 1.3±1.3, p=0.002). SC patients had higher rates of comorbid mental disorders (93% vs. 81%, p=0.002), specifically posttraumatic stress disorder (23% vs. 7%, p=0.002), and suicide attempts (43% vs. 19%, p<0.001). At the 4-year endpoint, both patients with and without comorbidity displayed major improvements in psychopathology, severity of illness, functioning, quality of life and satisfaction with care.

CONCLUSIONS

SC is frequent in patients with severe psychotic disorders, even in the early psychosis phase. The magnitude of the problem underlines the need for regular screening, comprehensive assessment, preventive pharmacotherapy, and targeted SC management.

A genome-wide association study identifies two novel susceptibility loci and trans population polygenicity associated with bipolar disorder

Genome-wide association studies (GWASs) have identified several susceptibility loci for bipolar disorder (BD) and shown that the genetic architecture of BD can be explained by polygenicity, with numerous variants contributing to BD. In the present GWAS (Phase I/II), which included 2964 BD and 61 887 control subjects from the Japanese population, we detected a novel susceptibility locus at 11q12.2 (rs28456, P=6.4 × 10-9), a region known to contain regulatory genes for plasma lipid levels (FADS1/2/3). A subsequent meta-analysis of Phase I/II and the Psychiatric GWAS Consortium for BD (PGC-BD) identified another novel BD gene, NFIX (Pbest=5.8 × 10-10), and supported three regions previously implicated in BD susceptibility: MAD1L1 (Pbest=1.9 × 10-9), TRANK1 (Pbest=2.1 × 10-9) and ODZ4 (Pbest=3.3 × 10-9). Polygenicity of BD within Japanese and trans-European-Japanese populations was assessed with risk profile score analysis. We detected higher scores in BD cases both within (Phase I/II) and across populations (Phase I/II and PGC-BD). These were defined by (1) Phase II as discovery and Phase I as target, or vice versa (for 'within Japanese comparisons', Pbest~10-29, R2~2%), and (2) European PGC-BD as discovery and Japanese BD (Phase I/II) as target (for 'trans-European-Japanese comparison,' Pbest~10-13, R2~0.27%). This 'trans population' effect was supported by estimation of the genetic correlation using the effect size based on each population (liability estimates~0.7). These results indicate that (1) two novel and three previously implicated loci are significantly associated with BD and that (2) BD 'risk' effect are shared between Japanese and European populations.

Genome-wide association studies of bipolar disorder: A systematic review of recent findings and their clinical implications

Recent advances in molecular genetics have enabled assessments of the associations among genetic variants (e.g., single-nucleotide polymorphisms) and susceptibility for complex diseases, including psychiatric disorders. Specifically, genome-wide association studies (GWAS), meta-analyses of the GWAS summary statistics, and mega-analyses (which use raw data, not summary statistics) of GWAS have provided revolutionary results and have identified numerous susceptibility genes or single-nucleotide polymorphisms. By using several tens of thousands of subjects, >40 genes have been identified as being associated with susceptibility for bipolar disorder so far. The purpose of this systematic review was to summarize the recent findings of bipolar disorder GWAS and discuss their clinical implications.

Telomere Length and Bipolar Disorder

Variation in telomere length is heritable and is currently considered a promising biomarker of susceptibility for neuropsychiatric disorders, particularly because of its association with memory function and hippocampal morphology. Here, we investigate telomere length in connection to familial risk and disease expression in bipolar disorder (BD). We used quantitative PCRs and a telomere-sequence to single-copy-gene-sequence ratio method to determine telomere length in genomic DNA extracted from buccal smears from 63 patients with BD, 74 first-degree relatives (49 relatives had no lifetime psychopathology and 25 had a non-BD mood disorder), and 80 unrelated healthy individuals. Participants also underwent magnetic resonance imaging to determine hippocampal volumes and cognitive assessment to evaluate episodic memory using the verbal paired associates test. Telomere length was shorter in psychiatrically well relatives (p=0.007) compared with unrelated healthy participants. Telomere length was also shorter in relatives (regardless of psychiatric status; p<0.01) and patients with BD not on lithium (p=0.02) compared with lithium-treated patients with BD. In the entire sample, telomere length was positively associated with left and right hippocampal volume and with delayed recall. This study provides evidence that shortened telomere length is associated with familial risk for BD. Lithium may have neuroprotective properties that require further investigation using prospective designs.

Mechanisms underlying metabolic disturbances associated with psychosis and antipsychotic drug treatment

The increase in cardiovascular disease and reduced life expectancy in schizophrenia likely relate to an increased prevalence of metabolic disturbances. Such metabolic risk factors in schizophrenia may result from both symptom-related effects and aetiological factors. However, a major contributory factor is that of treatment with antipsychotic drugs. These drugs differ in effects on body weight; the underlying mechanisms are not fully understood and may vary between drugs, but may include actions at receptors associated with the hypothalamic control of food intake. Evidence supports 5-hydroxytryptamine receptor 2C and dopamine D2 receptor antagonism as well as antagonism at histamine H1 and muscarinic M3 receptors. These M3 receptors may also mediate the effects of some drugs on glucose regulation. Several antipsychotics showing little propensity for weight gain, such as aripiprazole, have protective pharmacological mechanisms, rather than just the absence of a hyperphagic effect. In addition to drug differences, there is large individual variation in antipsychotic drug-induced weight gain. This pharmacogenetic association reflects genetic variation in several drug targets, including the 5-hydroxytryptamine receptor 2C, as well as genes involved in obesity and metabolic disturbances. Thus predictive genetic testing for drug-induced weight gain would represents a first step towards personalised medicine addressing this severe and problematic iatrogenic disease.

Reduced cardiac autonomic response to deep breathing: A heritable vulnerability trait in patients with schizophrenia and their healthy first-degree relatives

Reduced resting heart rate variability (HRV) has been observed in patients with schizophrenia and their relatives, suggesting genetic predispositions. However, findings have not been consistent. We assessed cardiac autonomic response to deep breathing in first-degree relatives of patients with schizophrenia (n=45; 26 female; aged 39.69±14.82 years). Data were compared to healthy controls (n=45; 26 female; aged 38.27±9.79 years) matched for age, gender, body mass index and physical activity as well as to unmedicated patients with acute schizophrenia (n=45; 25 female; aged 37.31±12.65 years). Electrocardiograms were recorded under supine resting and deep-breathing conditions (10-12breaths/min). We measured HRV components including variance, low-frequency (LF) power, which may reflect baroreflex function, high-frequency (HF) power, which reflects cardiac parasympathetic activity, and LF/HF ratio, which may reflect sympatho-vagal balance. Patients rather than relatives exhibited lower resting-state HRV (variance, LF, and HF) than controls. As expected, deep breathing induced an increase in variance and HF-HRV in controls. However, such a response was significantly reduced in both patients and their relatives. In conclusion, the diminished cardiac autonomic reactivity to deep breathing seen in patients and their unaffected relatives indicates that this pattern of cardiac autonomic dysregulation may be regarded as a genetic trait marker for schizophrenia.

Polygenic risk for type 2 diabetes mellitus among individuals with psychosis and their relatives

BACKGROUND

An elevated prevalence of Type 2 diabetes (T2D) has been observed in people with psychotic disorders and their relatives compared to the general population. It is not known whether this population also has increased genetic risk for T2D.

METHODS

Subjects included probands with schizophrenia, schizoaffective disorder, or psychotic bipolar I disorder, their first-degree relatives without psychotic disorders, and healthy controls, who participated in the Bipolar Schizophrenia Network for Intermediate Phenotypes study. We constructed sets of polygenic risk scores for T2D (PGRST2D) and schizophrenia (PGRSSCHIZ) using publicly available data from genome-wide association studies. We then explored the correlation of PGRST2D with psychiatric proband or relative status, and with self-reported diabetes. Caucasians and African-Americans were analyzed separately. We also evaluated correlations between PGRSSCHIZ and diabetes mellitus among Caucasian probands and their relatives.

RESULTS

In Caucasians, PGRST2D was correlated with self-reported diabetes mellitus within probands, but was not correlated with proband or relative status in the whole sample. In African-Americans, a PGRST2D based on selected risk alleles for T2D in this population did not correlate with proband or relative status. PGRSSCHIZ was not correlated with self-reported diabetes within Caucasian probands.

CONCLUSION

Differences in polygenic risk for T2D do not explain the increased prevalence of diabetes mellitus observed in psychosis probands and their relatives.

Impaired glucose metabolism moderates the course of illness in bipolar disorder

BACKGROUND

The longitudinal course of bipolar disorder (BD) is highly heterogeneous, and is moderated by the presence of general medical comorbidities. This study aimed to investigate the moderating effects of impaired glucose metabolism (IGM) on variables of illness course and severity in a BD population.

METHODS

Fifty-five patients with BD were evaluated. All subjects were evaluated with respect to current and past psychiatric and medical disorders, as well as lifetime use of any medication. Body mass index (BMI) and metabolic parameters were obtained. IGM was operationalized as pre-diabetes or type 2 diabetes mellitus.

RESULTS

Thirty (54.5%) individuals had IGM. After adjustment for age, gender, ethnicity, alcohol use, smoking, BMI and past and current exposure to psychotropic medications, individuals with IGM, when compared to euglycemic participants, had an earlier age of onset (RR: 0.835, p=0.024), longer illness duration (RR: 1.754, p=0.007), a higher number of previous manic/hypomanic episodes (RR: 1.483, p=0.002) and a higher ratio of manic/hypomanic to depressive episodes (RR: 1.753, p=0.028). Moreover, we observed a moderating effect of IGM on the association between number of mood episodes and other variables of illness course, with the correlation between lifetime mood episodes and frequency of episodes being significantly greater in the IGM subgroup (RR: 1.027, p=0.029). All associations observed herein remained significant after adjusting for relevant confounding factors (e.g. age, alcohol and tobacco use, exposure to psychotropic agents, BMI).

LIMITATIONS

Cross-sectional design, small sample size.

CONCLUSIONS

Comorbid IGM may be a key moderator of illness progression in BD.

Cardiac Autonomic Dysfunction in Patients with Schizophrenia and Their Healthy Relatives - A Small Review

The majority of excess mortality among people with schizophrenia seems to be caused by cardiovascular complications, and in particular, coronary heart disease. In addition, the prevalence of heart failure and arrhythmias is increased in this population. Reduced efferent vagal activity, which has been consistently described in these patients and their healthy first-degree relatives, might be one important mechanism contributing to their increased cardiac mortality. A decrease in heart rate variability and complexity was often shown in unmedicated patients when compared to healthy controls. In addition, faster breathing rates, accompanied by shallow breathing, seem to influence autonomic cardiac functioning in acute unmedicated patients substantially. Moreover, low-physical fitness is a further and independent cardiac risk factor present in this patient population. Interestingly, new studies describe chronotropic incompetence during physical exercise as an important additional risk factor in patients with schizophrenia. Some studies report a correlation of the autonomic imbalance with the degree of positive symptoms (i.e., delusions) and some with the duration of disease. The main body of psychiatric research is focused on mental aspects of the disease, thereby neglecting obvious physical health needs of these patients. Here, a joint effort is needed to design interventional strategies in everyday clinical settings to improve physical health and quality of life.