Diagnostic tests and treatment procedures performed prior to cardiovascular death in individuals with severe mental illness

OBJECTIVE

To examine whether severe mental illnesses (i.e., schizophrenia or bipolar disorder) affected diagnostic testing and treatment for cardiovascular diseases in primary and specialized health care.

METHODS

We performed a nationwide study of 72 385 individuals who died from cardiovascular disease, of whom 1487 had been diagnosed with severe mental illnesses. Log-binomial regression analysis was applied to study the impact of severe mental illnesses on the uptake of diagnostic tests (e.g., 24-h blood pressure, glucose/HbA1c measurements, electrocardiography, echocardiography, coronary angiography, and ultrasound of peripheral vessels) and invasive cardiovascular treatments (i.e., revascularization, arrhythmia treatment, and vascular surgery).

RESULTS

Patients with and without severe mental illnesses had similar prevalences of cardiovascular diagnostic tests performed in primary care, but patients with schizophrenia had lower prevalences of specialized cardiovascular examinations (prevalence ratio (PR) 0.78; 95% CI 0.73-0.85). Subjects with severe mental illnesses had lower prevalences of invasive cardiovascular treatments (schizophrenia, PR 0.58; 95% CI 0.49-0.70, bipolar disorder, PR 0.78; 95% CI 0.66-0.92). The prevalence of invasive cardiovascular treatments was similar in patients with and without severe mental illnesses when cardiovascular disease was diagnosed before death.

CONCLUSION

Better access to specialized cardiovascular examinations is important to ensure equal cardiovascular treatments among individuals with severe mental illnesses.

Undiagnosed cardiovascular disease prior to cardiovascular death in individuals with severe mental illness

OBJECTIVE

To examine whether individuals with schizophrenia (SCZ) or bipolar disorder (BD) had equal likelihood of not being diagnosed with cardiovascular disease (CVD) prior to cardiovascular death, compared to individuals without SCZ or BD.

METHODS

Multivariate logistic regression analysis including nationwide data of 72 451 cardiovascular deaths in the years 2011-2016. Of these, 814 had a SCZ diagnosis and 673 a BD diagnosis in primary or specialist health care.

RESULTS

Individuals with SCZ were 66% more likely (OR: 1.66; 95% CI: 1.39-1.98), women with BD were 38% more likely (adjusted OR: 1.38; 95% CI: 1.04-1.82), and men with BD were equally likely (OR: 0.88, 95% CI: 0.63-1.24) not to be diagnosed with CVD prior to cardiovascular death, compared to individuals without SMI. Almost all (98%) individuals with SMI and undiagnosed CVD had visited primary or specialized somatic health care prior to death, compared to 88% among the other individuals who died of CVD.

CONCLUSION

Individuals with SCZ and women with BD are more likely to die due to undiagnosed CVD, despite increased risk of CVD and many contacts with primary and specialized somatic care. Strengthened efforts to prevent, recognize, and treat CVD in individuals with SMI from young age are needed.

Genetic risk scores and family history as predictors of schizophrenia in Nordic registers

BACKGROUND

Family history is a long-standing and readily obtainable risk factor for schizophrenia (SCZ). Low-cost genotyping technologies have enabled large genetic studies of SCZ, and the results suggest the utility of genetic risk scores (GRS, direct assessments of inherited common variant risk). Few studies have evaluated family history and GRS simultaneously to ask whether one can explain away the other.

METHODS

We studied 5959 SCZ cases and 8717 controls from four Nordic countries. All subjects had family history data from national registers and genome-wide genotypes that were processed through the quality control procedures used by the Psychiatric Genomics Consortium. Using external training data, GRS were estimated for SCZ, bipolar disorder (BIP), major depression, autism, educational attainment, and body mass index. Multivariable modeling was used to estimate effect sizes.

RESULTS

Using harmonized genomic and national register data from Denmark, Estonia, Norway, and Sweden, we confirmed that family history of SCZ and GRS for SCZ and BIP were risk factors for SCZ. In a joint model, the effects of GRS for SCZ and BIP were essentially unchanged, and the effect of family history was attenuated but remained significant. The predictive capacity of a model including GRS and family history neared the minimum for clinical utility.

CONCLUSIONS

Combining national register data with measured genetic risk factors represents an important investigative approach for psychotic disorders. Our findings suggest the potential clinical utility of combining GRS and family history for early prediction and diagnostic improvements.

Evidence for genetic heterogeneity between clinical subtypes of bipolar disorder

We performed a genome-wide association study of 6447 bipolar disorder (BD) cases and 12 639 controls from the International Cohort Collection for Bipolar Disorder (ICCBD). Meta-analysis was performed with prior results from the Psychiatric Genomics Consortium Bipolar Disorder Working Group for a combined sample of 13 902 cases and 19 279 controls. We identified eight genome-wide significant, associated regions, including a novel associated region on chromosome 10 (rs10884920; P=3.28 × 10-8) that includes the brain-enriched cytoskeleton protein adducin 3 (ADD3), a non-coding RNA, and a neuropeptide-specific aminopeptidase P (XPNPEP1). Our large sample size allowed us to test the heritability and genetic correlation of BD subtypes and investigate their genetic overlap with schizophrenia and major depressive disorder. We found a significant difference in heritability of the two most common forms of BD (BD I SNP-h2=0.35; BD II SNP-h2=0.25; P=0.02). The genetic correlation between BD I and BD II was 0.78, whereas the genetic correlation was 0.97 when BD cohorts containing both types were compared. In addition, we demonstrated a significantly greater load of polygenic risk alleles for schizophrenia and BD in patients with BD I compared with patients with BD II, and a greater load of schizophrenia risk alleles in patients with the bipolar type of schizoaffective disorder compared with patients with either BD I or BD II. These results point to a partial difference in the genetic architecture of BD subtypes as currently defined.

Prevalence and predictors of anxiety and depression among esophageal cancer patients prior to surgery

This study aims to establish the prevalence and predictors of anxiety and depression among esophageal cancer patients, post-diagnosis but prior to curatively intended surgery. This was a cross-sectional study using data from a hospital-based prospective cohort study, carried out at St Thomas' Hospital, London. Potential predictor variables were retrieved from medical charts and self-report questionnaires. Anxiety and depression were measured prior to esophageal cancer surgery, using the Hospital Anxiety and Depression Scale. Prevalence of anxiety and depression was calculated using the established cutoff (scores ≥8 on each subscale) indicating cases of 'possible-probable' anxiety or depression, and multivariable logistic regression analyses were performed to examine predictors of emotional distress. Among the 106 included patients, 36 (34%) scored above the cutoff (≥8) for anxiety and 24 (23%) for depression. Women were more likely to report anxiety than men (odds ratio 4.04, 95% confidence interval 1.45-11.16), and patients reporting limitations in their activity status had more than five times greater odds of reporting depression (odds ratio 6.07, 95% confidence interval 1.53-24.10). A substantial proportion of esophageal cancer patients report anxiety and/or depression prior to surgery, particularly women and those with limited activity status, which highlights a need for qualified emotional support.

Age at fatherhood: heritability and associations with psychiatric disorders

BACKGROUND

Advancing paternal age has been linked to psychiatric disorders. These associations might be caused by the increased number of de novo mutations transmitted to offspring of older men. It has also been suggested that the associations are confounded by a genetic liability for psychiatric disorders in parents. The aim of this study was to indirectly test the confounding hypotheses by examining if there is a genetic component to advancing paternal age and if men with a genetic liability for psychiatric disorders have children at older ages.

METHOD

We examined the genetic component to advancing paternal age by utilizing the twin model in a cohort of male twins (N = 14 679). We also studied ages at childbirth in men with or without schizophrenia, bipolar disorder and/or autism spectrum disorder. Ages were examined in: (1) healthy men, (2) affected men, (3) healthy men with an affected sibling, (4) men with healthy spouses, (5) men with affected spouses, and (6) men with healthy spouses with an affected sibling.

RESULTS

The twin analyses showed that late fatherhood is under genetic influence (heritability = 0.33). However, affected men or men with affected spouses did not have children at older ages. The same was found for healthy individuals with affected siblings. Instead, these men were generally having children at younger ages.

CONCLUSION

Although there is a genetic component influencing late fatherhood, our data suggest that the associations are not explained by psychiatric disorders or a genetic liability for psychiatric disorders in the parent.

A genome-wide association study of kynurenic acid in cerebrospinal fluid: implications for psychosis and cognitive impairment in bipolar disorder

Elevated cerebrospinal fluid (CSF) levels of the glia-derived N-methyl-D-aspartic acid receptor antagonist kynurenic acid (KYNA) have consistently been implicated in schizophrenia and bipolar disorder. Here, we conducted a genome-wide association study based on CSF KYNA in bipolar disorder and found support for an association with a common variant within 1p21.3. After replication in an independent cohort, we linked this genetic variant-associated with reduced SNX7 expression-to positive psychotic symptoms and executive function deficits in bipolar disorder. A series of post-mortem brain tissue and in vitro experiments suggested SNX7 downregulation to result in a caspase-8-driven activation of interleukin-1β and a subsequent induction of the brain kynurenine pathway. The current study demonstrates the potential of using biomarkers in genetic studies of psychiatric disorders, and may help to identify novel drug targets in bipolar disorder.

ViPAR: a software platform for the Virtual Pooling and Analysis of Research Data

Background: Research studies exploring the determinants of disease require sufficient statistical power to detect meaningful effects. Sample size is often increased through centralized pooling of disparately located datasets, though ethical, privacy and data ownership issues can often hamper this process. Methods that facilitate the sharing of research data that are sympathetic with these issues and which allow flexible and detailed statistical analyses are therefore in critical need. We have created a software platform for the Virtual Pooling and Analysis of Research data (ViPAR), which employs free and open source methods to provide researchers with a web-based platform to analyse datasets housed in disparate locations.

Methods: Database federation permits controlled access to remotely located datasets from a central location. The Secure Shell protocol allows data to be securely exchanged between devices over an insecure network. ViPAR combines these free technologies into a solution that facilitates ‘virtual pooling’ where data can be temporarily pooled into computer memory and made available for analysis without the need for permanent central storage.

Results: Within the ViPAR infrastructure, remote sites manage their own harmonized research dataset in a database hosted at their site, while a central server hosts the data federation component and a secure analysis portal. When an analysis is initiated, requested data are retrieved from each remote site and virtually pooled at the central site. The data are then analysed by statistical software and, on completion, results of the analysis are returned to the user and the virtually pooled data are removed from memory.

Conclusions: ViPAR is a secure, flexible and powerful analysis platform built on open source technology that is currently in use by large international consortia, and is made publicly available at [ http://bioinformatics.childhealthresearch.org.au/software/vipar/ ].

Cognition and autonomic function in schizophrenia: inferior cognitive test performance in electrodermal and niacin skin flush non-responders

BACKGROUND

Patients with schizophrenia suffer from a broad range of cognitive disturbances. The impact in terms of functional outcome is significant. There are also several reports of disturbed autonomic regulation in the disease. The present study examined cognitive function as well as psychophysiological parameters in patients with schizophrenia and healthy controls.

METHODS

Twenty-five patients and 14 controls were investigated with electrodermal activity (EDA), an oral niacin skin flush test and a comprehensive neurocognitive test program including the Wechsler battery (WAIS-R), Fingertapping Test, Trail Making Test, Verbal Fluency, Benton Visual Retention Test, Wisconsin Card Sorting Test and Rey Auditory Verbal Learning Test.

RESULTS

The patients generally had inferior test results compared to controls. Further analysis revealed that the EDA non-responding patient group explained this variation with significant lower test results than controls. On executive tests, EDA non-responders also performed significantly worse than EDA responding patients. The small group of niacin non-responding patients exhibited an even lower overall test performance. Delayed niacin flush also correlated inversely with psychomotor function and IQ in the patients.

CONCLUSION

The findings support the hypothesis of a neurodevelopment disturbance affecting both autonomic function and higher cortical function in schizophrenia.

Copy number variation in schizophrenia in Sweden

Schizophrenia (SCZ) is a highly heritable neuropsychiatric disorder of complex genetic etiology. Previous genome-wide surveys have revealed a greater burden of large, rare copy number variations (CNVs) in SCZ cases and identified multiple rare recurrent CNVs that increase risk of SCZ although with incomplete penetrance and pleiotropic effects. Identification of additional recurrent CNVs and biological pathways enriched for SCZ CNVs requires greater sample sizes. We conducted a genome-wide survey for CNVs associated with SCZ using a Swedish national sample (4719 cases and 5917 controls). High-confidence CNV calls were generated using genotyping array intensity data, and their effect on risk of SCZ was measured. Our data confirm increased burden of large, rare CNVs in SCZ cases as well as significant associations for recurrent 16p11.2 duplications, 22q11.2 deletions and 3q29 deletions. We report a novel association for 17q12 duplications (odds ratio=4.16, P=0.018), previously associated with autism and mental retardation but not SCZ. Intriguingly, gene set association analyses implicate biological pathways previously associated with SCZ through common variation and exome sequencing (calcium channel signaling and binding partners of the fragile X mental retardation protein). We found significantly increased burden of the largest CNVs (>500 kb) in genes present in the postsynaptic density, in genomic regions implicated via SCZ genome-wide association studies and in gene products localized to mitochondria and cytoplasm. Our findings suggest that multiple lines of genomic inquiry--genome-wide screens for CNVs, common variation and exonic variation--are converging on similar sets of pathways and/or genes.

The KMO allele encoding Arg452 is associated with psychotic features in bipolar disorder type 1, and with increased CSF KYNA level and reduced KMO expression

The kynurenine pathway metabolite kynurenic acid (KYNA), modulating glutamatergic and cholinergic neurotransmission, is increased in cerebrospinal fluid (CSF) of patients with schizophrenia or bipolar disorder type 1 with psychotic features. KYNA production is critically dependent on kynurenine 3-monooxygenase (KMO). KMO mRNA levels and activity in prefrontal cortex (PFC) are reduced in schizophrenia. We hypothesized that KMO expression in PFC would be reduced in bipolar disorder with psychotic features and that a functional genetic variant of KMO would associate with this disease, CSF KYNA level and KMO expression. KMO mRNA levels were reduced in PFC of bipolar disorder patients with lifetime psychotic features (P=0.005, n=19) or schizophrenia (P=0.02, n=36) compared with nonpsychotic patients and controls. KMO genetic association to psychotic features in bipolar disorder type 1 was studied in 493 patients and 1044 controls from Sweden. The KMO Arg(452) allele was associated with psychotic features during manic episodes (P=0.003). KMO Arg(452) was studied for association to CSF KYNA levels in an independent sample of 55 Swedish patients, and to KMO expression in 717 lymphoblastoid cell lines and 138 hippocampal biopsies. KMO Arg(452) associated with increased levels of CSF KYNA (P=0.03) and reduced lymphoblastoid and hippocampal KMO expression (P≤0.05). Thus, findings from five independent cohorts suggest that genetic variation in KMO influences the risk for psychotic features in mania of bipolar disorder patients. This provides a possible mechanism for the previous findings of elevated CSF KYNA levels in those bipolar patients with lifetime psychotic features and positive association between KYNA levels and number of manic episodes.

Are prenatal, obstetric, and infant complications associated with postpartum psychosis among women with pre-conception psychiatric hospitalisations?

OBJECTIVE

To examine the associations of maternal and infant complications with postpartum hospitalisation for psychosis in women with a pre-conception history of psychiatric hospitalisation.

DESIGN

Population-based study.

SETTING

Swedish medical birth register.

POPULATION

Primiparous women who gave birth between 1 January 1987 and 31 December 2001, and who had a pre-conception history of psychiatric hospitalisation but who were not hospitalised during pregnancy (n = 1842).

METHODS

International Classification of Diseases (ICD) codes were used to identify prenatal, obstetric, postpartum maternal complications, and newborn health conditions. We used multivariable logistic regression to describe the associations between maternal and infant health conditions and the odds for postpartum hospitalisation for psychosis.

MAIN OUTCOME MEASURE

Psychiatric hospitalisation within 90 days of delivery.

RESULTS

Compared with women who did not have a postpartum psychiatric hospitalisation, hospitalised women were at 2.3 times higher odds (95% CI 1.0-4.9) of having non-psychiatric puerperium complications (e.g. infection, lactation problems or venous complications). No other maternal complications were associated with postpartum psychiatric hospitalisation. Although their infants were at no higher odds for health complications, the offspring of women who had a postpartum psychiatric hospitalisation were at 4.1 times higher odds (95% CI 1.3-12.6) of death within the first 365 days of life than those of women who were not hospitalised.

CONCLUSIONS

We found no prenatal indicators of postpartum risk for psychiatric hospitalisation among high-risk women, but they had higher odds of postpartum pregnancy-related medical problems and, rarely, offspring death.

Functional gene group analysis identifies synaptic gene groups as risk factor for schizophrenia

Schizophrenia is a highly heritable disorder with a polygenic pattern of inheritance and a population prevalence of ~1%. Previous studies have implicated synaptic dysfunction in schizophrenia. We tested the accumulated association of genetic variants in expert-curated synaptic gene groups with schizophrenia in 4673 cases and 4965 healthy controls, using functional gene group analysis. Identifying groups of genes with similar cellular function rather than genes in isolation may have clinical implications for finding additional drug targets. We found that a group of 1026 synaptic genes was significantly associated with the risk of schizophrenia (P=7.6 × 10(-11)) and more strongly associated than 100 randomly drawn, matched control groups of genetic variants (P<0.01). Subsequent analysis of synaptic subgroups suggested that the strongest association signals are derived from three synaptic gene groups: intracellular signal transduction (P=2.0 × 10(-4)), excitability (P=9.0 × 10(-4)) and cell adhesion and trans-synaptic signaling (P=2.4 × 10(-3)). These results are consistent with a role of synaptic dysfunction in schizophrenia and imply that impaired intracellular signal transduction in synapses, synaptic excitability and cell adhesion and trans-synaptic signaling play a role in the pathology of schizophrenia.

Genome-wide association study in a Swedish population yields support for greater CNV and MHC involvement in schizophrenia compared with bipolar disorder

Schizophrenia (SCZ) and bipolar disorder (BD) are highly heritable psychiatric disorders with overlapping susceptibility loci and symptomatology. We conducted a genome-wide association study (GWAS) of these disorders in a large Swedish sample. We report a new and independent case-control analysis of 1507 SCZ cases, 836 BD cases and 2093 controls. No single-nucleotide polymorphisms (SNPs) achieved significance in these new samples; however, combining new and previously reported SCZ samples (2111 SCZ and 2535 controls) revealed a genome-wide significant association in the major histocompatibility complex (MHC) region (rs886424, P=4.54 × 10(-8)). Imputation using multiple reference panels and meta-analysis with the Psychiatric Genomics Consortium SCZ results underscored the broad, significant association in the MHC region in the full SCZ sample. We evaluated the role of copy number variants (CNVs) in these subjects. As in prior reports, deletions were enriched in SCZ, but not BD cases compared with controls. Singleton deletions were more frequent in both case groups compared with controls (SCZ: P=0.003, BD: P=0.013), whereas the largest CNVs (>500 kb) were significantly enriched only in SCZ cases (P=0.0035). Two CNVs with previously reported SCZ associations were also overrepresented in this SCZ sample: 16p11.2 duplications (P=0.0035) and 22q11 deletions (P=0.03). These results reinforce prior reports of significant MHC and CNV associations in SCZ, but not BD.

Validity of bipolar disorder hospital discharge diagnoses: file review and multiple register linkage in Sweden

OBJECTIVE

Hospital discharge registers (HDRs) are frequently used in epidemiological research. However, the validity of several important psychiatric diagnostic entities, including bipolar disorder, remains uncertain. Hence, we aimed to develop an optimal algorithm for register-based identification of DSM-IV-TR bipolar disorder.

METHOD

We identified potential cases in the Swedish national HDR using two separate discharge diagnoses of bipolar disorder according to ICD versions 8-10 during January 1, 1973 to December 31, 2004. In a randomly selected subsample of 135 cases from the county of Sörmland, two senior psychiatrists reassessed the diagnostic status based on patients' medical records. We scrutinized false-positive cases and modified the initial algorithm to improve positive predictive value while minimizing false negatives. Finally, we externally validated resulting caseness algorithms by linking HDR diagnostic data with best-estimate clinical diagnoses from the National Quality Assurance Register for Bipolar Disorder (BipoläR), dispensed lithium prescriptions from the National Prescribed Drug Register, and the ICD-10 diagnoses from the National Outpatient Register respectively.

RESULTS

The algorithm with two discharge diagnoses of bipolar disorder yielded a positive predictive value of 0.81. Modification by excluding individuals diagnosed with ICD-8 296.20 (manic-depressive psychosis, depressed type), and/or ICD-9 296.B (unipolar affective psychosis, melancholic form), gave a positive positive predictive value of 0.92. The modified algorithm also had statistically superior external validity compared with the original algorithm.

CONCLUSION

Our findings suggest that DSM-IV-TR bipolar disorder caseness based on two inpatient episodes with a bipolar disorder diagnosis is sufficiently sensitive and specific to be used in further epidemiological study of bipolar disorder.

Test-retest stability of the oral niacin test and electrodermal activity in patients with schizophrenia

In schizophrenia, well-replicated findings support an attenuated niacin skin-flush response. We have previously reported a delayed skin-flush after niacin ingestion and also an association between niacin non-responding and electrodermal non-responding in schizophrenia. The stability of the niacin and electrodermal tests was now studied in a test-retest design. An additional aim was to assess the association previously found. Twenty-three patients with schizophrenia underwent two sessions 3 months apart during which an oral niacin test was conducted and electrodermal activity was measured. Despite similar values for niacin outcome variables at the group level, there was high intraindividual variation. Test-retest stability for the oral niacin test was thus low, although a trend toward correlation for the dichotomous response criterion was found. Most electrodermal measures correlated between baseline and retest. A significant association between the tests was again found; niacin non-responding implied electrodermal non-responding, providing further support for a common underlying aberration in schizophrenia.

Prenatal ultrasound exposure and children's school performance at age 15-16: follow-up of a randomized controlled trial

OBJECTIVE

To evaluate the association between prenatal ultrasound exposure and school performance at 15-16 years of age.

METHODS

The study population consisted of children born to women who participated in a randomized controlled trial on the second-trimester ultrasound examination in Sweden from 1985 to 1987. Information about the children's grades when graduating from primary school and information on socioeconomic factors was obtained from Swedish nationwide registers. Comparisons were made using linear and logistic regression analyses according to randomization to ultrasound, ultrasound exposure in the second trimester and ultrasound exposure at any time during pregnancy. Boys and girls were analyzed separately.

RESULTS

Of the 4756 singleton children from the randomized trial, we identified 4458 (94%) in the National School Register. There were no statistically significant differences in school performance for boys or girls according to randomization or exposure to ultrasound in the second trimester. Compared to those who were unexposed, boys exposed to ultrasound at least once at any time during fetal life had a tendency towards lower mean school grades in general (-4.39 points; 95% CI, -9.59 to 0.81 (max possible, 320) points) and in physical education (-0.45 points; 95% CI, -0.91 to 0.01 (max possible, 20) points), but the differences did not reach significance.

CONCLUSION

In general, routine ultrasound examination in the second trimester had no effect on overall school performance in teenagers.

Risk of suicide among operated and non-operated patients hospitalised for peptic ulcers

BACKGROUND

Some small studies have reported high risk of suicide after surgical treatment for peptic ulcer. The aim of the present study was to explore the risk of suicide in hospitalised gastric ulcer and duodenal ulcer patients separately among operated and non-operated cohorts.

METHODS

Retrospective cohorts of 163,579 non-operated patients with gastric ulcer or duodenal ulcer and 28,112 patients with surgical treatment for ulcer, recorded in the Swedish Inpatient Register since 1965, were followed from the first hospitalisation, or operation for the surgery cohort, until death, any cancer, emigration, or 31 December 2003. Standardised mortality ratios (SMRs) were calculated, and Poisson regression produced adjusted relative risk estimates among operated and non-operated patients.

RESULTS

Non-operated patients hospitalised for peptic ulcer showed a 70% excess risk of suicide (SMR 1.7, 95% CI 1.6 to 1.9) and those who underwent operation had a 60% increased risk (SMR 1.6, 95% CI 1.4 to 1.8). The risk of suicide was very high during the first year after hospitalisation (SMR 4.0, 95% CI 3.4 to 4.7) and more marked among women, patients under 70 and patients hospitalised without complications of ulcer. Both gastric ulcer and duodenal ulcer patients had high risk of suicide completion.

CONCLUSION

Hospitalised patients with gastric ulcer or duodenal ulcer have an increased risk of suicide regardless of surgical treatment. These patients, especially women, are at very high risk during the first year after first hospitalisation/operation. The evaluation and management of suicidal thoughts in patients in medical settings should be further considered.

Scholastic achievement at age 16 and risk of schizophrenia and other psychoses: a national cohort study

BACKGROUND

There is abundant evidence that schizophrenia is associated with cognitive deficits in childhood. However, previous studies investigating school performance have been inconclusive. Furthermore, there are several biological and social factors that could confound the association. We investigated whether school performance at age 16 is associated with risk of adult schizophrenia and other psychoses in a large national cohort, while controlling for multiple confounders.

METHOD

Using a national sample of 907 011 individuals born in Sweden between 1973 and 1983, we used Cox regression to assess whether scholastic achievement at age 15-16 predicted hospital admission for psychosis between ages 17 and 31, adjusting for potential confounders.

RESULTS

Poor school performance was associated with increased rates of schizophrenia [hazard ratio (HR) 3.9, 95% confidence interval (CI) 2.8-5.3], schizo-affective disorder (HR 4.2, 95% CI 1.9-9.1) and other psychoses (HR 3.0, 95% CI 2.3-4.0). Receiving the lowest (E) grade was significantly associated with risk for schizophrenia and other psychoses in every school subject. There was no evidence of confounding by migrant status, low birthweight, hypoxia, parental education level or socio-economic group.

CONCLUSIONS

Poor school performance across all domains is strongly associated with risk for schizophrenia and other psychoses.

Niacin skin-flush response and electrodermal activity in patients with schizophrenia and healthy controls

Patients with schizophrenia have in different studies shown reduced niacin sensitivity and lower electrodermal activity (EDA) after auditory stimulation. Peripheral mediation of prostaglandins may have a physiological role in both responses. This motivates study of both niacin response and electrodermal responding in the same patients with schizophrenia. Thirty patients with schizophrenia and 17 controls were investigated with EDA and thereafter given 200mg niacin orally with continuous assessment of skin temperature. The patients showed a delayed temperature increase after niacin ingestion (P=0.002) and a higher frequency of electrodermal non-responding (P<0.05). Response/non-response for niacin correlated with EDA response/non-response in the patient group (P=0.009). The niacin test revealed a slower vasodilation reaction in the patients. The association between response patterns for the niacin test and EDA suggests that a common aberration in skin physiology may be of importance for both reactions in schizophrenia.

School achievements and schizophrenia: a case-control study

OBJECTIVE

To compare school performance during middle childhood and adolescence among subjects later diagnosed with schizophrenia and their peers.

METHOD

School records were ascertained from archives in 76 acutely symptomatic schizophrenic patients and 146 controls matched for gender and graded by the same teachers.

RESULTS

At age 9, no differences in yearly graded school subjects were found. At 12, cases had higher marks in drawing/art and a tendency to excel in language and religion. At 15, the proficient performance in drawing/art remained, but cases performed worse than controls in gymnastics. The cases reported high frequency of school adaptation problems. Severity of psychotic symptoms at admission was associated with lower and declining marks.

CONCLUSION

Schizophrenic patients seem to perform as well as their classmates in most subjects taught in compulsory basic school. Findings indicating specific talents in artistic ability and impairments in motor development need to be further investigated.

Very preterm birth, birth trauma, and the risk of anorexia nervosa among girls

BACKGROUND

Obstetrical complications, based on parental recall, have been reported to be associated with development of anorexia nervosa. We used prospectively collected data about pregnancy and perinatal factors to examine the subsequent development of anorexia nervosa.

METHODS

This population-based, case-control study was nested in cohorts defined by all liveborn girls in Sweden from 1973 to 1984. From the Swedish Inpatient Register, 781 girls had been discharged from any hospital in Sweden with a main diagnosis of anorexia nervosa at the age of 10 to 21 years. For each case, 5 controls were randomly selected, individually matched by year and hospital of birth (n = 3905). Conditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for potential risk factors.

RESULTS

Increased risk of anorexia nervosa was found for girls with a cephalhematoma (OR, 2.4; 95% CI, 1.4-4.1) and for very preterm birth (< or = 32 completed gestational weeks) (OR, 3.2; 95% CI, 1.6-6.2). In very preterm births, girls who were small for gestational age faced higher risks (OR, 5.7; 95% CI, 1.1-28.7) than girls with higher birth weight for gestational age (OR, 2.7; 95% CI, 1.2-5.8).

CONCLUSIONS

Our results show that perinatal factors, possibly reflecting brain damage, had independent associations with anorexia nervosa. These risk factors may uncover the mechanisms underlying the development of the disorder, even if only a fraction of cases of anorexia nervosa may be attributable to perinatal factors.

Prenatal and perinatal risk factors for schizophrenia, affective psychosis, and reactive psychosis of early onset: case-control study

OBJECTIVE

To examine prenatal and perinatal risk factors for subsequent development of schizophrenia and affective and reactive psychosis.

DESIGN

Three population based, case-control studies conducted within a Sweden-wide cohort of all children born during 1973-9. This was done by linking individual data from the Swedish birth register, which represents 99% of all births in Sweden, to the Swedish inpatient register.

SUBJECTS

Patients listed in inpatient register as having been first admitted to hospital aged 15-21 years with a main diagnosis of schizophrenia (n=167), affective psychosis (n=198), or reactive psychosis (n=292). For each case, five controls were selected.

MAIN OUTCOME MEASURES

Risks of schizophrenia and affective and reactive psychosis in relation to pregnancy and perinatal characteristics.

RESULTS

Schizophrenia was positively associated with multiparity (odds ratio 2.0), maternal bleeding during pregnancy (odds ratio 3.5), and birth in late winter (odds ratio 1.4). Affective psychosis was associated with uterine atony (odds ratio 2.2) and late winter birth (odds ratio 1.5). Reactive psychosis was related to multiparity (odds ratio 2.1). An increased risk for schizophrenia was found in boys who were small for their gestational age at birth (odds ratio 3.2), who were number four or more in birth order (odds ratio 3.6), and whose mothers had had bleeding during late pregnancy (odds ratio 4.0).

CONCLUSIONS

A few specific pregnancy and perinatal factors were associated with the subsequent development of psychotic disorder, particularly schizophrenia, in early adult life. The association of small size for gestational age and bleeding during pregnancy with increased risk of early onset schizophrenia among males could reflect placental insufficiency.

Perinatal characteristics and schizophrenia: electrodermal activity as a mediating link in a vulnerability-stress perspective

Vulnerability-stress models of schizophrenia assert that the disorder results from an interaction between genetic or biologically acquired vulnerability and unfavourable environmental conditions. As our knowledge of early environmental factors for schizophrenia evolves, the question of links between early factors and a development of schizophrenia becomes more important. In this article, we analyse the relationship between obstetrical complications (OCs) and adult schizophrenia and methodological concerns in the search for pre- and perinatal risk factors. We review findings of aberrant electrodermal activity in schizophrenic patients and suggest that OCs may induce insults to cerebral structures that are critically involved in the control of orienting and of autonomic responses.

Electrodermal activity and obstetric complications in schizophrenia

The pregnancy and birth records of 79 schizophrenic patients, from whom adult electrodermal data were available, were systematically evaluated for obstetric complications using 34 criteria of nonoptimality in pregnancy, delivery, and postpartum periods. Patients with many obstetric complications had lower levels of electrodermal activity. For frequency of skin conductance responses and spontaneous fluctuations in skin conductance, the association was more evident for women than for men. However, the ratio of stimulus-elicited to spontaneous skin conductance responses showed a reliable association with obstetric complications without any gender differences. The relationship between obstetric complications and electrodermal activity was interpreted in terms of neurodevelopmental insults resulting in structural brain abnormalities interfering with orienting and electrodermal activity.

Electrodermal activity and obstetric complications in schizophrenia

The pregnancy and birth records of 79 schizophrenic patients, from whom adult electrodermal data were available, were systematically evaluated for obstetric complications using 34 criteria of nonoptimality in pregnancy, delivery, and postpartum periods. Patients with many obstetric complications had lower levels of electrodermal activity. For frequency of skin conductance responses and spontaneous fluctuations in skin conductance, the association was more evident for women than for men. However, the ratio of stimulus-elicited to spontaneous skin conductance responses showed a reliable association with obstetric complications without any gender differences. The relationship between obstetric complications and electrodermal activity was interpreted in terms of neurodevelopmental insults resulting in structural brain abnormalities interfering with orienting and electrodermal activity.

Relationships between social support, social coping and life events in the relapse of schizophrenic patients

The vulnerability-stress model for schizophrenia posits that relapses are at least partly determined by interacting triggering and protecting psychosocial factors. This study examined social support and general coping style in 42 consecutively admitted DSM:III schizophrenic patients, who were followed prospectively for up to four years. In a second part of the study, a subgroup of the patients were interviewed using the Life Event and Difficulty Schedule 9 months after discharge or at relapse. Patients contented with low social integration had a higher relapse rate over four years than patients lacking of social provisions, but wanting more. We found an excess of life events three weeks before relapse compared to events reported in the non-relapsing group. Suggesting a buffering effect of social factors, time between life event and relapse was significantly extended among patients with a high availability of attachment and a coping strategy characterised of active support seeking.

Prenatal and neonatal risk factors for schizophrenia

BACKGROUND

The present study examines the effects of independent, single pre- and perinatal risk factors and rates of obstetric complications upon the subsequent development of schizophrenia.

METHOD

This study was based on prospectively recorded birth records of 107 cases (82 with schizophrenic disorders and 25 with other psychotic reactions) and 214 controls, individually matched by gender and time and place of birth. Variables univariately associated with significantly elevated risk were entered in a logistic regression model.

RESULTS

A high non-optimality summary score (> or = 7 complications of 34 possible) was a significant risk estimate for the total index group (OR 4.58, 95% CI 1.74-12.03) and the 82 schizophrenic patients (OR 3.67, CI 1.30-10.36). Patients with 2-6 complications also had an increased, although lower, risk (OR 1.67, CI 1.02-2.75). A disproportionate birth weight for body length (OR 3.57, CI 1.77-7.19) and a small head circumference (OR 3.93, CI 1.32-11.71) were the strongest independent risk factors.

CONCLUSIONS

A contribution of obstetric complications to the risk of schizophrenia was confirmed. Only aberrations in physical size remained as individual independent risk factors.

Electrodermal activity and social network as predictors of outcome of episodes in schizophrenia

The predictive value of electrodermal activity and social network was examined among 48 consecutively admitted schizophrenic patients. The patients were followed from an initial admission, through hospital stay, discharge, follow-up (M = 31 months), and possible relapse. Outcome variables were the length of stay in the hospital at the key episode and time to relapse, defined as a marked exacerbation or return of schizophrenic symptoms requiring inpatient or expansion of outpatient treatment. Multivariate analyses showed that a psychosocial variable, the availability of attachment, was the only independent predictor of length of stay in the hospital. Age at admission was a strong predictor of time to relapse. Age interacted with both outcome and electrodermal activity, and young electrodermal nonresponders were found to have the shortest time to relapse. At the 1-year follow-up, a main relapse effect was found for patients with a low skin conductance level.

Early parental death: relation to electrodermal orienting response and gender in schizophrenia

The aim of the present study was to examine age at parental loss by death and its relation to electrodermal orienting response and sex in schizophrenia. Forty-four DSM-III schizophrenic inpatients were exposed to a series of moderately intense tones in a standard orienting habituation paradigm, while skin conductance was recorded. The twenty-three patients who failed to respond to any of the first two tones were found to be younger when they lost their first parent compared to the 21 responders. When the 44 patients were divided according to sex, the females were found to be younger than the males when parental loss occurred. Finally, when multivariate analyses were performed, it was found that both responding/nonresponding and sex provided almost equally large independent contribution to the prediction of parental loss.