Age of onset in familial and sporadic schizophrenia

Evidence for increased DNA damage repair in the postmortem brain of the high stress-response group of schizophrenia

Background

Schizophrenia (SZ) is a disorder diagnosed by specific symptoms and duration and is highly heterogeneous, clinically and pathologically. Although there are an increasing number of studies on the association between genetic and environmental factors in the development of SZ, the actual distribution of the population with different levels of influence of these factors has not yet been fully elucidated. In this study, we focused on stress as an environmental factor and stratified SZ based on the expression levels of stress-responsive molecules in the postmortem prefrontal cortex.

Methods

We selected the following stress-responsive molecules: interleukin (IL) -1β, IL-6, IL-10, tumor necrosis factor-α, interferon-γ, glucocorticoid receptor, brain-derived neurotrophic factor, synaptophysin, S100 calcium-binding protein B, superoxide dismutase, postsynaptic density protein 95, synuclein, apolipoprotein A1 (ApoA1), ApoA2, and solute carrier family 6 member 4. We performed RNA sequencing in the prefrontal gray matter of 25 SZ cases and 21 healthy controls and conducted a hierarchical cluster analysis of SZ based on the gene expression levels of stress-responsive molecules, which yielded two clusters. After assessing the validity of the clusters, they were designated as the high stress-response SZ group and the low stress-response SZ group, respectively. Ingenuity Pathway Analysis of differentially expressed genes (DEGs) between clusters was performed, and Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining was conducted on four cases each in the high and low stress-response SZ groups to validate DNA damage.

Results

We found higher prevalence of family history of SZ in the low stress-response SZ group (0/3 vs. 5/4, p = 0.04). Pathway analysis of DEGs between clusters showed the highest enrichment for DNA double-strand break repair. TUNEL staining showed a trend toward a lower percentage of TUNEL-positive cells in the high stress-response SZ group.

Conclusion

Our results suggest that there are subgroups of SZ with different degrees of stress impact. Furthermore, the pathophysiology of these subgroups may be associated with DNA damage repair. These results provide new insights into the interactions and heterogeneity between genetic and environmental factors.

Defects in Bioenergetic Coupling in Schizophrenia

Synaptic neurotransmission relies on maintenance of the synapse and meeting the energy demands of neurons. Defects in excitatory and inhibitory synapses have been implicated in schizophrenia, likely contributing to positive and negative symptoms as well as impaired cognition. Recently, accumulating evidence has suggested that bioenergetic systems, important in both synaptic function and cognition, are abnormal in psychiatric illnesses such as schizophrenia. Animal models of synaptic dysfunction demonstrated endophenotypes of schizophrenia as well as bioenergetic abnormalities. We report findings on the bioenergetic interplay of astrocytes and neurons and discuss how dysregulation of these pathways may contribute to the pathogenesis of schizophrenia, highlighting metabolic systems as important therapeutic targets.

Family history of psychosis and outcome of people with schizophrenia in rural China: 14-year follow-up study

OBJECTIVE

This study examined the differences in 14-year outcomes of persons with schizophrenia with and without family history of psychosis in a rural community in China.

METHODS

All participants with schizophrenia (n=510) aged 15 years and older were identified in a 1994 epidemiological investigation of 123,572 people and followed up in 2004 and 2008 in Xinjin County, Chengdu, China.

RESULTS

Individuals with positive family history of schizophrenia had significantly younger age of first onset than those with negative family history of schizophrenia in 1994 and 2004. Compared with individuals with negative family history of schizophrenia, those with positive family history of schizophrenia had significantly higher rate of homelessness and lower rate of death due to other reasons in 10-year (2004) and 14-year follow-up (2008). There were no significantly differences of mean scores on PANSS, SDSS and GAF in 2008 between positive and negative family history groups.

CONCLUSIONS

The positive family history of schizophrenia is strongly related to younger age of onset, and may predict a poorer long-term outcome (e.g., higher rate of homelessness) in persons with schizophrenia in the rural community. The findings have implications for further studies on specific family-related mechanisms on clinical treatment and rehabilitation, as well as for planning and delivering of community-based mental health services.

Family history of psychiatric disorders and age at first contact in schizophrenia: An epidemiological study

Background

The risk for schizophrenia has been associated with a family history of this and other psychiatric disorders. The relationship between age at first contact and family history of psychiatric illness is not certain.

Aims

To estimate the risks for schizophrenia associated with a range of psychiatric diagnoses in family members and to investigate the relationship between these risks and age at first contact for schizophrenia.

Method

A nested case–control study design was employed. Psychiatric admission data and socio-economic data were available for 7704 cases admitted between 1981 and 1998 in Denmark, 192 590 gender- and age-matched controls, and for the parents and siblings of all subjects.

Results

Controlling for socio-economic factors, risk for schizophrenia was associated with a family history of all psychiatric disorders except substance misuse and independently with a family history of suicide. The risk for schizophrenia associated with a family history of psychiatric disorders decreased as age at first contact increased.

Conclusions

Risk for schizophrenia is associated with a range of psychiatric disorders in family members and these risks are not constant across the risk period.

Gender differences in one-year outcomes of first-presentation psychosis patients in inner-city UK Early Intervention Services

AIM

Men and women have historically been shown to differ in their presentation and outcome of psychotic disorders and thus are likely to have different treatment needs. It is unclear whether Early Intervention Services (EIS) are able to provide equitable care for both men and women presenting for the first time with psychosis. The main aim of this study was to explore gender differences for first-presentation psychosis patients at the time of their referral to inner-city EIS and their outcomes 1 year later.

METHODS

Audit data were utilized from 1098 first-presentation psychosis patients from seven EIS across London, UK, collected via the computerized MiData package. Binary logistic regression was employed to detect potential associations between gender and (i) initial clinical presentation (including duration of untreated psychosis, pathways to care, risk behaviours); and (ii) 1-year clinical and functional outcomes.

RESULTS

At entry to EIS, male patients presented with more violent behaviour whereas female patients had more suicide attempts. Following 1 year of EIS care, men still presented as more violent towards others whereas women were more likely to have been admitted to a psychiatric ward.

CONCLUSION

Gender differences in clinical outcome, service use and risk behaviours were apparent within the first year of specialist psychosis care. This may be partly due to the different pathways to care taken by men and women and differences in clinical presentation. Greater focus on the specific needs of each gender by EIS in detection and intervention is required to improve equality of outcome.

Genetic Association of TCF4 and AKT1 Gene Variants with the Age at Onset of Schizophrenia

BACKGROUND

Age at onset (AAO) is a known prognostic indicator for schizophrenia and is hypothesized to correlate with cognition and symptom severity. TCF4 and AKT1 are schizophrenia risk genes involved in cognitive functions. The current study examined the interactive effects of TCF4 and AKT1 variants with gender, family history of psychiatric disorders and ethnicity on the AAO of schizophrenia.

METHODS

This study consisted of 322 patients with schizophrenia meeting the DSM-IV criteria. Six single nucleotide polymorphisms (SNPs) of TCF4 (rs12966547, rs8766, rs2958182, rs9960767, rs10401120 and rs17512836) and seven AKT1 SNPs (rs2498804, rs3803304, rs2494732, rs3730358, rs1130214, rs2498784 and rs3803300) were genotyped using the TaqMan® SNP genotyping-based assays method. The relationship of AAO with each variant was investigated using analyses of covariance.

RESULTS

Among the TCF4 variants, rs12966547 (p = 0.024) and rs8766 (p = 0.021) were significantly associated with earlier AAO. We found a lower average AAO in patients with the AA genotype of rs12966547, while the CT genotype of rs8766 was demonstrated to have a protective effect on AAO. For rs8766, there was significant gene × gender interaction (p = 0.012) in influencing AAO. However, these results were not significant after false discovery rate correction. Significant gene × ethnicity interactions were observed to influence AAO (p < 0.05). The Kaplan-Meier curve of the minor AA genotype of rs12966547 displayed a significant trend (p = 0.008) for onset after 19 years of age. Similarly, the minor CC genotype of rs8766 showed a significantly (p = 0.034) lower AAO compared to the TT genotype.

CONCLUSION

Our analyses suggest that individual risk genotypes may influence the risk of schizophrenia in an age-specific manner.

Childhood dyspraxia predicts adult-onset nonaffective-psychosis-spectrum disorder

Several neurological variables have been investigated as premorbid biomarkers of vulnerability for schizophrenia and other related disorders. The current study examined whether childhood dyspraxia predicted later adult nonaffective-psychosis-spectrum disorders. From a standardized neurological examination performed with children (aged 10-13) at genetic high risk of schizophrenia and controls, several measures of dyspraxia were used to create a scale composed of face/head dyspraxia, oral articulation, ideomotor dyspraxia (clumsiness), and dressing dyspraxia (n = 244). Multinomial logistic regression showed higher scores on the dyspraxia scale predict nonaffective-psychosis-spectrum disorders relative to other psychiatric disorders and no mental illness outcomes, even after controlling for genetic risk, χ2 (4, 244) = 18.61, p < .001. Findings that symptoms of dyspraxia in childhood (reflecting abnormalities spanning functionally distinct brain networks) specifically predict adult nonaffective-psychosis-spectrum disorders are consistent with a theory of abnormal connectivity, and they highlight a marked early-stage vulnerability in the pathophysiology of nonaffective-psychosis-spectrum disorders.

Distinct disruptions of resting-state functional brain networks in familial and sporadic schizophrenia

Clinical and brain structural differences have been reported between patients with familial and sporadic schizophrenia; however, little is known about the brain functional differences between the two subtypes of schizophrenia. Twenty-six patients with familial schizophrenia (PFS), 26 patients with sporadic schizophrenia (PSS) and 26 healthy controls (HC) underwent a resting-state functional magnetic resonance imaging. The whole-brain functional network was constructed and analyzed using graph theoretical approaches. Topological properties (including global, nodal and edge measures) were compared among the three groups. We found that PFS, PSS and HC exhibited common small-world architecture of the functional brain networks. However, at a global level, only PFS showed significantly lower normalized clustering coefficient, small-worldness, and local efficiency, indicating a randomization shift of their brain networks. At a regional level, PFS and PSS disrupted different neural circuits, consisting of abnormal nodes (increased or decreased nodal centrality) and edges (decreased functional connectivity strength), which were widely distributed throughout the entire brain. Furthermore, some of these altered network measures were significantly correlated with severity of psychotic symptoms. These results suggest that familial and sporadic schizophrenia had segregated disruptions in the topological organization of the intrinsic functional brain network, which may be due to different etiological contributions.

Comorbid substance use disorders in schizophrenia: a latent class approach

Schizophrenia is a complex psychiatric disorder with a characteristic disease course and heterogeneous etiology. While substance use disorders and a family history of psychosis have individually been identified as risk factors for schizophrenia, it is less well understood if and how these factors are related. To address this deficiency, we examined the relationship between substance use disorders and family history of psychosis in a sample of 1219 unrelated patients with schizophrenia. The lifetime rate of substance use disorders in this sample was 50%, and 30% had a family history of psychosis. Latent class mixture modeling identified three distinct patient subgroups: (1) individuals with low probability of substance use disorders; (2) patients with drug and alcohol abuse, but no symptoms of dependence; and (3) patients with substance dependence. Substance use was related to being male, to a more severe disease course, and more acute symptoms at assessment, but not to an earlier age of onset of schizophrenia or a specific pattern of positive and negative symptoms. Furthermore, substance use in schizophrenia was not related to a family history of psychosis. The results suggest that substance use in schizophrenia is an independent risk factor for disease severity and onset.

The Relative Importance of Family History, Gender, Mode of Onset, and Age at Onsetin Predicting Clinical Features of First-Episode Psychotic Disorders

OBJECTIVE

Family history of psychosis, gender, mode of onset, and age at onset are considered prognostic factors important to clinicians evaluating first-episode psychosis; yet, clinicians have little guidance as to how these four factors differentially predict early-course substance abuse, symptomatology, and functioning. We conducted a "head-to-head comparison" of these four factors regarding their associations with key clinical features at initial hospitalization. We also assessed potential interactions between gender and family history with regard to age at onset of psychosis and symptom severity.

METHODS

Consecutively admitted first-episode patients (n=334) were evaluated in two studies that rigorously assessed a number of early-course variables. Associations among variables of interest were examined using Pearson correlations, χ² tests, Student's t-tests, and 2×2 factorial analyses of variance.

RESULTS

Substance (nicotine, alcohol, and cannabis) abuse and positive symptom severity were predicted only by male gender. Negative symptom severity and global functioning impairments were predicted by earlier age at onset of psychosis. General psychopathology symptom severity was predicted by both mode of onset and age at onset. Interaction effects were not observed with regard to gender and family history in predicting age at onset or symptom severity.

CONCLUSIONS

The four prognostic features have differential associations with substance abuse, domains of symptom severity, and global functioning. Gender and age at onset of psychosis appear to be more predictive of clinical features at the time of initial evaluation (and thus presumably longer term outcomes) than the presence of a family history of psychosis and a more gradual mode of onset.

The Concept of Schizophrenia: From Unity to Diversity

After over 100 years of research without clarifying the aetiology of schizophrenia, a look at the current state of knowledge in epidemiology, genetics, precursors, psychopathology, and outcome seems worthwhile. The disease concept, created by Kraepelin and modified by Bleuler, has a varied history. Today, schizophrenia is considered a polygenic disorder with onset in early adulthood, characterized by irregular psychotic episodes and functional impairment, but incident cases occur at all ages with marked differences in symptoms and social outcome. Men’s and women’s lifetime risk is nearly the same. At young age, women fall ill a few years later and less severely than men, men more rarely and less severely later in life. The underlying protective effect of oestrogen is antagonized by genetic load. The illness course is heterogeneous and depressive mood the most frequent symptom. Depression and schizophrenia are functionally associated, and affective and nonaffective psychoses do not split neatly. Most social consequences occur at the prodromal stage. Neither schizophrenia as such nor its main symptom dimensions regularly show pronounced deterioration over time. Schizophrenia is neither a residual state of a neurodevelopmental disorder nor a progressing neurodegenerative process. It reflects multifactorial CNS instability, which leads to cognitive deficits and symptom exacerbations.

Postmortem brain: an underutilized substrate for studying severe mental illness

We propose that postmortem tissue is an underutilized substrate that may be used to translate genetic and/or preclinical studies, particularly for neuropsychiatric illnesses with complex etiologies. Postmortem brain tissues from subjects with schizophrenia have been extensively studied, and thus serve as a useful vehicle for illustrating the challenges associated with this biological substrate. Schizophrenia is likely caused by a combination of genetic risk and environmental factors that combine to create a disease phenotype that is typically not apparent until late adolescence. The complexity of this illness creates challenges for hypothesis testing aimed at understanding the pathophysiology of the illness, as postmortem brain tissues collected from individuals with schizophrenia reflect neuroplastic changes from a lifetime of severe mental illness, as well as treatment with antipsychotic medications. While there are significant challenges with studying postmortem brain, such as the postmortem interval, it confers a translational element that is difficult to recapitulate in animal models. On the other hand, data derived from animal models typically provide specific mechanistic and behavioral measures that cannot be generated using human subjects. Convergence of these two approaches has led to important insights for understanding molecular deficits and their causes in this illness. In this review, we discuss the problem of schizophrenia, review the common challenges related to postmortem studies, discuss the application of biochemical approaches to this substrate, and present examples of postmortem schizophrenia studies that illustrate the role of the postmortem approach for generating important new leads for understanding the pathophysiology of severe mental illness.

Family load estimates of schizophrenia and associated risk factors in a nation-wide population study of former child and adolescent patients up to forty years of age

OBJECTIVES

This nation-wide register-based study investigates the family load of schizophrenia (SZ) across three generations in affected families compared to control families. Furthermore the study compares the family load in case vs. control families considering the age of onset of the disorder in the cases. In addition, the study addresses the impact of certain socio-demographic risk factors, i.e. sex, region of residence, year of birth, month of birth, and maternal and paternal age at birth.

METHOD

A total of N=2020 child and adolescent psychiatric cases born between 1969 and 1985 registered in the Danish Central Psychiatric Register (DCPR) before the age of 18 developed SZ before the age of 40. N=5982 controls without any psychiatric diagnosis before age 18 were matched for age, sex, and residential region. Psychiatric diagnoses were also obtained on the first-degree relatives, i.e. parents, siblings, and offspring as a part of the Danish Three Generation Study (3GS). A family load was obtained by using various mixed regression models.

RESULTS

SZ did occur more often in case than in control families. Having a mother, father or a sibling with the disorder was proven to be a risk factor. The year of birth, the region of residence, and paternal age at birth (≥ 35) were associated with SZ. However, the family load was not dependent on age of onset of the case-proband. Furthermore, case relatives did not develop SZ earlier than control relatives.

CONCLUSIONS

These findings based on a very large and representative dataset provide further and solid evidence for the high family aggregation of SZ. The year of birth, the region of residence, and paternal age at birth play an additional role in the development of the disorder.

Family history of psychosis negatively impacts age at onset, negative symptoms, and duration of untreated illness and psychosis in first-episode psychosis patients

Family history (FH) of psychosis has been a focus of investigations attempting to explain the heterogeneity in schizophrenia. Previous studies have demonstrated that FH is associated with earlier age at onset, severity of positive and negative symptoms, and the duration of untreated illness (DUI). The current study examined the impact of FH on the clinical presentation and help-seeking behaviors of a well-characterized, first-episode sample. The present study utilized the Symptom Onset in Schizophrenia (SOS) Inventory, the Positive and Negative Syndrome Scale (PANSS), and structured interviews on FH to examine these relationships in a large (n=152) sample of predominantly African American patients. Results showed that patients with a first-degree FH of psychosis had a younger age at onset of both the prodrome and psychosis, but did not differ in duration of prodromal period. Furthermore, FH and sex interacted to influence severity of negative, but not positive symptoms. Finally, FH interacted with sex to influence both the DUI and DUP in that only males with FH had longer DUI and DUP. The findings have implications for understanding the impact of specific family-related mechanisms on both clinical and help-seeking factors, as well as for informing future family-based intervention efforts.

Environmental risk factors and their impact on the age of onset of schizophrenia: Comparing familial to non-familial schizophrenia

BACKGROUND AND AIMS

Several risk factors for schizophrenia have yet been identified. The aim of our study was to investigate how certain childhood and adolescent risk factors predict the age of onset of psychosis in patients with and without a familial component (i.e. a relative with schizophrenia or schizoaffective disorder).

METHODS

Aside from the age of onset of psychosis, we examined the risk factors for schizophrenia including obstetric complications, birth during winter or spring, behavioral deviances or delayed motor and speech development, exposure to adverse life events and exposure to substance use within a group of 100 patients (45 female, 55 male) with a mean age (± standard deviation) of 35.15 ± 13.21.

RESULTS

Birth complications and cannabis abuse are predictors for an earlier onset of schizophrenia in patients with non-familial schizophrenia. No environmental risk factors for an earlier age of onset in familial schizophrenia have been identified.

CONCLUSIONS

Certain environmental risk factors for schizophrenia seem to have an impact on the age of onset of psychosis in non-familial schizophrenia, they do not seem to have an impact on familial schizophrenia.

Similarities in early course among men and women with a first episode of schizophrenia and schizophreniform disorder

The aims of this study were to analyze the presence of gender differences in the phenotypic expression of schizophrenia at the onset of illness and to explore whether these differences determine clinical and functional outcome 2 years after the initiation of treatment. Data from 231 first-episode-psychosis non-substance-dependent patients (156 men and 75 women) participating in a large-scale naturalistic open-label trial with risperidone were recorded at inclusion and months 1, 6, 12, and 24. Men presented a significant earlier age of onset (24.89 years vs. 29.01 years in women), poorer premorbid functioning, and a higher presence of prodromal and baseline negative symptoms. Women were more frequently married or lived with their partner and children and more frequently presented acute stress during the year previous to onset than men. No other significant clinical or functional differences were detected at baseline. The mean dose of antipsychotic treatment was similar for both genders during the study, and no significant differences in UKU scores were found. The number of hospitalizations was similar between groups, and adherence was more frequent among women. At the 2-year follow-up, both groups obtained significant improvements in outcome measures: PANSS, CGI severity, and GAF scores. Significant gender * time interactions were detected for negative and general PANSS subscales, with the improvement being more pronounced for men. However, no differences were detected for the mean scores obtained during the study in any outcome measure, and the final profile was similar for men and women. Our results suggest that although the initial presentation of schizophrenia can differ according to gender, these differences are not sufficient enough to determine differentiated outcome 2 years after the initiation of treatment in non-substance-dependent patients. The influence of gender on the early course of schizophrenia does not seem to be clinically or functionally decisive in this population.

Gender differences in Singaporean Chinese patients with schizophrenia

The purpose of this study was to compare gender differences in age of onset of illness, clinical features and prescription patterns in Chinese schizophrenia patients in Singapore. A cross-sectional study was conducted which recruited 903 subjects diagnosed with schizophrenia from the Institute of Mental Health between 2005 and 2008. Information on age of onset of schizophrenia, body mass index (BMI), psychiatric family history and current medication was collected via a standardised collection form. Symptom severity was assessed with Positive and Negative Syndrome Scale (PANSS). Differences in age of onset of schizophrenia illness, clinical features and prescription patterns were compared between gender groups. Among sporadic schizophrenia cases, female subjects demonstrated a bimodal distribution in age of onset of illness, and had a significantly later age of illness onset compared with male subjects. For subjects with family history of psychiatric disorder, no significant gender differences were found in age of onset of illness. Female subjects had significantly higher BMI, higher proportion of diabetes mellitus, lower negative symptom scores and were prescribed more atypical antipsychotics and antidepressants compared with male subjects. Male subjects after age 50 were prescribed a lower antipsychotic dose, but this difference was not observed in female subjects. In conclusion, we found differences in age of onset of schizophrenia, severity of negative symptoms and prescription patterns between the male and female gender groups in Chinese schizophrenia patients in Singapore. These differences were consistent with findings from Caucasian population, and could possibly be explained by influences of oestrogen.

Service utilization in a tertiary psychiatric care setting in South India

OBJECTIVE

To carry out an audit reviewing the utilization of psychiatric services and types of disorders presenting to a tertiary care psychiatry hospital in a developing Asian country.

METHOD

Consecutive adult patients who came for detailed consultation in 1 year were included in this study. A senior consultant psychiatrist reconfirmed the diagnosis in each patient who underwent detailed psychiatric evaluation. Psychiatric evaluation consists of clinical history from the patients and the relatives and a mental state examination. Data was obtained from the detailed work up evaluation psychiatry records of these patients.

RESULTS

Mood disorder was the most common diagnosis followed by substance use disorders and psychotic disorders (ICD 10). There is a substantial delay of more than 2-5 years for seeking treatment in most disorders including schizophrenia. More than 80% of the population directly seeks treatment at this tertiary hospital. Sixty-four percent of the patients came for at least one follow up.

CONCLUSION

The result suggests the urgent need for strengthening community care in India and similar low and middle-income countries for early and optimal treatment.

Mitochondrial DNA (mtDNA) and schizophrenia

The poorly understood aetiology of schizophrenia is known to involve a major genetic contribution even though the genetic factors remain elusive. Most genetic studies are based on Mendelian rules and focus on the nuclear genome, but current studies indicate that other genetic mechanisms are probably involved. This review focuses on mitochondrial DNA (mtDNA), a maternally inherited, 16.6-Kb molecule crucial for energy production that is implicated in numerous human traits and disorders. The aim of this review is to summarise the studies that have explored mtDNA in schizophrenia patients and those which provide evidence for its implication in this illness. Alterations in mitochondrial morphometry, brain energy metabolism, and enzymatic activity in the mitochondrial respiratory chain suggest a mitochondrial dysfunction in schizophrenia that could be related to the genetic characteristics of mtDNA. Moreover, evidence of maternal inheritance and the presence of schizophrenia symptoms in patients suffering from a mitochondrial disorder related to an mtDNA mutation suggest that mtDNA is involved in schizophrenia. The association of specific variants has been reported at the molecular level; however, additional studies are needed to determine whether the mitochondrial genome is involved in schizophrenia.

The impact of a family history of psychosis on age-at-onset and positive and negative symptoms of schizophrenia: a meta-analysis

The results of research on the relation of family history (FH) of psychosis with clinical presentation in schizophrenia have been mixed. To date, there have been no comprehensive reviews that have examined this body of research. The current review quantitatively evaluates research on the relation of FH with two aspects of schizophrenia, age-at-onset and symptom presentation. Studies investigating the influence of a FH on age-at-onset (N=15 studies), age-at-onset and sex (N=12 studies), and/or positive (N=11 studies) and negative symptoms (N=12 studies) in patients with schizophrenia were included in the meta-analyses. Results showed that FH has a small but significant impact on age-at-onset as well as negative symptoms. Of most interest was the finding that sex differences in age-at-onset are not observed in samples with a FH. Furthermore, there was a significant interaction between FH and sex with respect to negative symptoms. The findings of the current review are discussed in light of the diathesis-stress model. Theoretical assumptions and empirical research are reviewed to support the notion that FH influences susceptibility and presentation through similar mechanisms. Implications of the current findings, limitations of the review, and directions for future research are highlighted.

Prevalence of psychotic and non-psychotic disorders in relatives of patients with a first episode psychosis

BACKGROUND

Family members of individuals with schizophrenia suffer from elevated rates of schizophrenia-spectrum disorders (SSD) and other forms of psychopathology. However, few studies have examined familial psychopathology in probands with a first episode of psychosis (FEP). We systematically evaluated family history in patients experiencing an affective or non-affective FEP.

METHODS

The Family Interview for Genetic Studies was used to obtain diagnostic information on all first- and second-degree relatives of probands admitted to a specialized FEP program. Probands were 94 previously untreated patients suffering from a first-episode of affective or schizophrenia spectrum psychosis, aged 14 to 30. The interview ascertained diagnoses of psychotic disorders, affective disorders, substance-use disorders (SUD), and schizophrenia-related personality disorders.

RESULTS

One in five probands (19.1%) had a history of psychosis among their first-degree relatives, while 34.0% had any relative with psychosis. Fewer probands had a family history of SSD (7.4% with a first-degree history and 18.1% with a history among any relatives). Over half (53.2%) of probands had a first-degree relative with Major Depressive Disorder, and 38.3% had a first-degree relative with a SUD. Overall, 69.9% of probands had a first-degree relative with a mental disorder. The proportion of probands with a family history of any of these diagnoses did not vary by proband diagnosis (affective or SS Psychosis), though probands with co-morbid SUD were more likely to have a family history of substance abuse.

CONCLUSIONS

Diverse psychopathology is commonly present in families of FEP patients and may imply a generalized vulnerability to psychiatric disorders to be greater in such families compared to specific vulnerability to SS or affective psychosis. These findings may also have implications for provision of care for the probands.

Neuroanatomical differences between familial and sporadic schizophrenia and their parents: an optimized voxel-based morphometry study

Symptomatic differences have been reported between patients with familial and sporadic schizophrenia. The present study examined neuroanatomical differences between the two subgroups and their parents using voxel-based morphometry. High-resolution T1-weighted images were obtained using 3 Tesla magnetic resonance imaging from 20 patients with schizophrenia (familial subgroup, n=10; sporadic subgroup, n=10), 20 of their parents (familial subgroup, n=10; sporadic subgroup, n=10) and 20 healthy volunteers. Gray matter density (GMD) was compared between groups on a voxel-by-voxel basis. Compared with the sporadic patients, the familial patients had significantly reduced GMD in the thalamus bilaterally. Reduction of GMD in bilateral thalami was also found in familial parents in comparison with sporadic parents. Compared with controls, both familial and sporadic patients had lower GMD involving bilateral insula, right temporal lobe, right occipital lobe, left lenticular nucleus and right cerebellum. However, only familial patients showed lower GMD than controls in the right thalamus. Compared with controls, only familial parents showed lower GMD in the right insula extending to the right temporal lobe and the right parietal lobule. The present data suggest that familial schizophrenia is associated with more severe structural abnormalities than sporadic schizophrenia, especially in the thalamus.

Age-related changes in the expression of schizophrenia susceptibility genes in the human prefrontal cortex

The molecular basis of complex neuropsychiatric disorders most likely involves many genes. In recent years, specific genetic variations influencing risk for schizophrenia and other neuropsychiatric disorders have been reported. We have used custom DNA microarrays and qPCR to investigate the expression of putative schizophrenia susceptibility genes and related genes of interest in the normal human brain. Expression of 31 genes was measured in Brodmann's area 10 (BA10) in the prefrontal cortex of 72 postmortem brain samples spanning half a century of human aging (18-67 years), each without history of neuropsychiatric illness, neurological disease, or drug abuse. Examination of expression across age allowed the identification of genes whose expression patterns correlate with age, as well as genes that share common expression patterns and that possibly participate in common cellular mechanisms related to the emergence of schizophrenia in early adult life. The expression of GRM3 and RGS4 decreased across the entire age range surveyed, while that of PRODH and DARPP-32 was shown to increase with age. NRG1, ERBB3, and NGFR show expression changes during the years of greatest risk for the development of schizophrenia. Expression of FEZ1, GAD1, and RGS4 showed especially high correlation with one another, in addition to the strongest mean levels of absolute correlation with all other genes studied here. All microarray data are available at NCBI's Gene Expression Omnibus: GEO Series accession number GSE11546 (http://www.ncbi.nlm.nih.gov/geo) [corrected]

Do women express and experience psychosis differently from men? Epidemiological evidence from the Australian National Study of Low Prevalence (Psychotic) Disorders

OBJECTIVE

To examine how women differ from men in their expression and experience of psychosis.

METHOD

Using an epidemiological sampling frame, 1090 cases of psychosis (schizophrenia, schizoaffective disorder, affective psychoses, and other psychoses) were randomly selected from a catchment of 1.1 million people as part of the Australian Study of Low Prevalence (Psychotic) Disorders. Women and men were compared with respect to their premorbid functioning, onset and course of illness, symptomatology, levels of disability and service utilization.

RESULTS

Results within diagnostic groupings confirm differences in how men and women experience and express their illness. Within each diagnostic group, women reported better premorbid functioning, a more benign illness course, lower levels of disability and better integration into the community than men. They were also less likely to have a chronic course of illness. There were no significant differences in age at onset. Differences between women across the diagnostic groups were more pronounced than differences between women and men within a diagnostic group. In particular, women with schizophrenia were severely disabled compared to other women.

CONCLUSIONS

These comparisons across diagnostic groupings are among the most systematic and comprehensive in the literature. It is likely that several mechanisms are needed to explain the differences. Greater social integration and functioning in women across diagnostic groups may well reflect culturally and socially determined gender differences. In contrast, variability and attenuated findings with respect to symptom profiles beg the question of biological mechanisms with some degree of specificity.

Positive family history is associated with persistent elevated emotional distress in schizophrenia: evidence from a 16-month follow-up study

There is some evidence that emotional reactivity to daily life stress is related to a genetic or familial liability to develop schizophrenia. However, it is unclear whether the emotional distress is elevated in schizophrenia patients with positive compared to negative family history. The aim of the study was to test the hypothesis that a persistent higher level of emotional distress in schizophrenia subjects is associated with a positive family history of schizophrenia. This study used the Talbieh Brief Distress Inventory (TBDI), the Positive and Negative Syndrome Scale (PANSS; including dysphoric mood, positive and negative subscales), Montgomery-Asberg Depression Rating Scale (MADRS), and the Distress Scale for Adverse Symptoms (DSAS) to investigate the difference in the magnitude of emotional distress scores between schizophrenia subjects with and without a positive family history of schizophrenia over time. Data were recorded for 69 multiplex family and 79 singleton patients at admission and about 16 months thereafter. No between-group differences were obtained in PANSS and DSAS scores. With regard to the TBDI: (a) both group of patients had no significant differences in emotional distress scores at admission; (b) patients with negative family history reported improvement in distress severity and depression severity (MADRS) 16 months after admission, while those with positive family history experienced persistent elevated emotional distress, mainly, on obsessiveness, and depression subscales; and (c) both groups of patients are characterized by elevated emotional distress at follow-up examination compared to healthy subjects. Thus, it appears that there is a strong association between positive family history and persistent elevated emotional distress. Because patients with positive and negative family history are likely to differ in genetic risk, our results suggest that long-term elevated levels of emotional distress may be related to a familial (environmental)/genetic vulnerability to schizophrenia.

Age-specific familial risks of psychotic disorders and schizophrenia: a nation-wide epidemiological study from Sweden

OBJECTIVE

This study analyzed men and women separately by age at hospital diagnosis of psychotic disorder or schizophrenia and by maternal or paternal disease after taking several possible confounders into account.

METHODS

The Multigeneration Register, in which all men and women born in Sweden from 1932 onwards are registered together with their parents, was linked to hospital data. This yielded 21,199 male and 19,029 female cases of psychotic disorders in addition to 12,799 paternal and 23,021 maternal cases of psychotic disorders (including schizophrenia). Standardized incidence ratios (SIRs) were calculated as the ratio of observed and expected number of cases among men and women with mothers and/or fathers affected by psychotic disorders or schizophrenia, compared with men and women whose mothers and/or fathers were not affected by psychotic disorders or schizophrenia.

RESULTS

The overall significant SIRs among men and women with a mother, father or both parents hospitalized for psychotic disorder varied between 2.86 and 20.30. Maternal transmission of psychotic disorder was stronger than paternal, and the highest SIRs were found in the youngest age groups. Similar results were found when the subgroup schizophrenia was analyzed separately. Maternal or paternal schizophrenia implied higher risks for the offspring than maternal or paternal psychotic disorders.

CONCLUSIONS

Hereditary factors have a strong influence on the onset of psychotic disorders and schizophrenia. Young people and individuals with both parents affected by these diseases need special attention as their SIRs were particularly increased.

Gender differences in 542 Chinese inpatients with schizophrenia

OBJECTIVE

To investigate gender differences in the onset and other clinical features of Han Chinese inpatients with schizophrenia.

METHODS

Five-hundred-and-forty-two Han Chinese inpatients with DSM-IV schizophrenia were assessed with the Positive and Negative Symptoms Scale (PANSS), the Brief Psychiatric Rating Scale (BPRS), the Global Assessment of Function scale (GAF) and locally-developed standardized data collection forms. Comparisons were made between male and female patients.

RESULTS

This is the largest study of gender differences in schizophrenia to be conducted in a Chinese population. In our sample, we found that schizophrenia onset occurred at a significantly earlier age in male patients compared to female patients and that late-onset schizophrenia (as defined by onset> or =45 years) was significantly more common in female patients. The paranoid subtype of schizophrenia was less common in male patients, males received higher daily doses of antipsychotics and demonstrated a different pattern of antipsychotic usage, being less likely to be treated with SGAs. Further, cigarette smoking was more common in male patients and male patients were more likely to be single or never married. By contrast, female patients showed a different pattern of ongoing symptoms and severity, being more likely to have persistent positive symptoms, more severe positive and affective symptoms, and a greater number of suicide attempts whereas male patients were more likely to show severe deterioration over time.

CONCLUSIONS

There are notable gender differences in the age at onset, treatment and a range of other clinical features in Han Chinese patients with schizophrenia. Such differences were largely consistent with those reported in Western studies. These gender differences need to be considered in the assessment and management of Chinese patients with schizophrenia.

The significance of family history in first-episode schizophrenia spectrum disorder

There have been inconsistent findings regarding the significance of family history of schizophrenia spectrum disorders in relation to presentation and course of illness. There has been little research relevant to this issue from first-episode patients. We examined the differences in premorbid adjustment, symptoms, and intellectual functioning between 28 first-episode schizophrenia spectrum patients with a history of such illness in first degree relatives and 28 matched patients without such a family history. The results indicate that whereas the 2 groups did not differ in presenting symptoms, those with a positive family history showed poorer intellectual functioning and less reduction in symptoms at 2 and 3 year follow-up and greater likelihood of abnormal electroencephalogram findings. The findings provide evidence that presence of a positive family history in first-episode patients is associated with a more pernicious form of illness.

Reduced N-acetyl-aspartate levels in schizophrenia patients with a younger onset age: a single-voxel 1H spectroscopy study

Schizophrenia is widely considered a neurodevelopmental disorder. The timing of psychosis onset may determine the degree of functional and biological deficits. In this study, the association between age of onset of psychosis and in vivo biochemical levels was assessed in first-episode, antipsychotic-naive (FEAN) schizophrenia subjects. We hypothesized greater biochemical deficits in the younger-onset FEAN subjects. In vivo, (1)H spectroscopy measurements of the left dorsolateral prefrontal cortex (DLPFC) were conducted on FEAN subjects (15 schizophrenia and 3 schizoaffective subjects) and healthy comparison subjects of comparable age and gender distribution (N=61). N-acetyl-aspartate was significantly lower in the left DLPFC of FEAN subjects as compared to healthy comparison subjects. However, there was a significant subject group-by-age interaction for N-acetyl-aspartate. Early-onset FEAN subjects showed lower N-acetyl-aspartate levels compared to the younger healthy comparison subjects, while adult-onset FEAN and older healthy comparison subjects did not differ. The lower N-acetyl-aspartate levels in the DLPFC of early-onset subjects suggest a reduction in functioning neurons or specifically a reduction in the proliferation of dendrites and synaptic connections, which is not apparent in the adult-onset schizophrenia subjects.

Etiological Heterogeneity and Intelligence Test Scores in Patients with Schizophrenia

Previous research has indicated that patients with a family history of schizophrenia show a greater degree of cognitive and neuropsychological impairment than patients without a family history. We examined the neurocognitive performance, using the WAIS-R, of 51 patients with a family history (familial) and 103 patients without a family history (sporadic) to determine if differences exist that may help to explain the heterogeneous neuropsychological profile of the illness. The family history groups did not differ with respect to gender, diagnosis, ethnicity, age, age of onset, education or duration of illness. Multivariate analyses, covarying for age of onset and education, showed the sporadic group performed significantly better than the familial group on the digit symbol and object assembly subtests, with a trend level difference in overall performance IQ score. Additionally, we identified significant gender differences in favor of males for full scale and verbal IQ, the information, digit span, block design, and arithmetic subtests, and at a trend level, the picture assembly subtest. The family history group differences reflect relative dysfunction in visual attention and scanning, visuomotor control, and spatial processing and reasoning. Overall, the results suggest that sporadic patients have better perceptual-organizational skills and faster speed of processing.

Subtyping schizophrenia: implications for genetic research

Phenotypic variability and likely extensive genetic heterogeneity have been confounding the search for the causes of schizophrenia since the inception of the diagnostic category. The inconsistent results of genetic linkage and association studies using the diagnostic category as the sole schizophrenia phenotype suggest that the current broad concept of schizophrenia does not demarcate a homogeneous disease entity. Approaches involving subtyping and stratification by covariates to reduce heterogeneity have been successful in the genetic study of other complex disorders, but rarely applied in schizophrenia research. This article reviews past and present attempts at delineating schizophrenia subtypes based on clinical features, statistically derived measures, putative genetic indicators, and intermediate phenotypes, highlighting the potential utility of multidomain neurocognitive endophenotypes.

Heritability of schizophrenia and major affective disorder as a function of age, in the presence of strong cohort effects

It remains unclear whether age at onset for major psychiatric disorders is a useful marker of etiologic and genetic heterogeneity. The authors examined how heritability of schizophrenia and major affective disorders varied with age at onset. The sample was drawn from a large archival data set collected by Lionel Penrose, comprising 3,109 families with two or more members first hospitalized in Ontario between 1874 and 1944. The authors studied 1,295 sibships with schizophrenia (n = 487), major affective disorder (n = 378), both (n = 234) or neither (n = 196) of these disorders. Proportional hazards models were used to estimate how the hazard of hospitalization for each disorder (schizophrenia or major affective disorder) varied with proband age at onset, adjusted for changes in age at onset distribution between 1874 and 1944. A sibling's risk of hospitalization for the same illness significantly increased for each 10-year decrease in age at onset of the proband both for schizophrenia (hazard ratio = 1.21, 95 % confidence interval: 1.06, 1.39), and for affective disorder (hazard ratio = 1.29,95 % CI: 1.14, 1.45). Gender of proband was unrelated to sibling risk of the same illness, and tests of interaction effects between proband age at onset and gender on sibling risk were nonsignificant.

Familiality in a five-factor model of schizophrenia psychopathology: findings from a 16-month follow-up study

We sought to examine stability associations between family history and variability of schizophrenia symptoms repeatedly examined during a naturalistic follow-up study. The Positive and Negative Syndrome Scale, the Insight and Treatment Attitudes Questionnaire, and the Abnormal Involuntary Movement Scale were administered to 69 patients with familial and 79 patients with sporadic schizophrenia, at hospital admission and at stabilization stage (about 16 months later). Analysis of covariance was applied to identify the association of symptom factors with familiality of schizophrenia. We found that schizophrenia patients with positive family histories had significantly higher dysphoric, activation and negative factors. However, familiality of activation and negative factors were dependent on additional variables such as age of onset (both factors), baseline ratings, insight, and side effects (negative factor). No significant association of family history with intensity of positive and autistic preoccupation factors was found. Familial schizophrenia is characterized by higher severity of dysphoric mood factors that may represent impaired emotional reactivity. It is suggested that dysphoric mood may be a useful phenotype for molecular genetic studies of schizophrenia with positive family history.

Explaining variation in the premorbid adjustment of schizophrenia patients: the role of season of birth and family history

Several studies have shown that patients with schizophrenia are more likely to be born in the winter and early spring than at any other time of the year. Furthermore, some studies have reported that winter-born patients differ from non-winter-born patients in terms of risk factors, symptoms, sensory abnormalities and brain morphology. Associations between season of birth and premorbid adjustment (PMA), however, are still unclear.

OBJECTIVE

The main purpose of this study was to determine whether winter-born and non-winter-born schizophrenia patients differ in terms of PMA and to examine how family history of schizophrenia-spectrum disorders may influence the association.

METHOD

Data on four PMA dimensions (attention, internalizing, externalizing and social problems) and family history were gathered from 37 schizophrenia patients (26 males and 11 females) and their mothers.

RESULTS

Non-winter-birth and a positive family history of schizophrenia-spectrum disorders were associated with worse PMA. Results suggest that, although no significant interaction was found, season of birth and family history appear to work together in explaining distinct dimensions of PMA.

Resting neural activity distinguishes subgroups of schizophrenia patients

BACKGROUND

Schizophrenia is etiologically heterogeneous. It is anticipated, but unproven, that subgroups will differ in neuropathology and that neuroimaging may reveal these differences. The optimal imaging condition may be at rest, where greater variability is observed than during cognitive tasks, which more consistently reveal hypofrontality. We previously demonstrated symptom and physiologic differences between familial and sporadic schizophrenia patients and hypothesized that the groups would show different resting regional cerebral blood flow (rCBF) patterns.

METHODS

Ten familial and sixteen sporadic schizophrenia patients and nine comparison subjects had single photon emission computed tomography imaging during passive visual fixation. Images were spatially normalized into Talairach coordinates and analyzed for group rCBF differences using SPM with a Z value threshold of 2.80, p < .001.

RESULTS

The subgroups had similar age, gender, illness duration, and medication treatment. Sporadic patients had hypofrontality (anterior cingulate, paracingulate cortices, left dorsolateral and inferior-orbitofrontal), whereas familial patients had left temporoparietal hypoperfusion; all of these regions show resting activity in healthy subjects. Both groups hyperperfused the cerebellum/pons and parahippocampal gyrus; additional hyperperfusion for sporadic patients was observed in the fusiform; familial patients also hyperperfused the hippocampus, dentate, uncus, amygdala, thalamus, and putamen.

CONCLUSIONS

Familial and sporadic schizophrenia patients had different resting rCBF profiles, supporting the hypothesis that certain subgroups have distinct neural underpinnings. Different neuropathologic processes among subgroups of schizophrenia patients may account for the prior contradictory results of resting imaging studies.

The investigation of cytosolic phospholipase A2 using ELISA

Two studies of the behaviour of cytosolic phospholipase A(2) (cPLA(2)) in the red blood cell (RBC), as measured by ELISA, are described. In the first study we show a significant increase in cPLA(2) in patients with schizophrenia compared to controls and suggest that this measure, if corroborated, could be used as a diagnostic marker. In a second study we found that washing the RBC introduced an unknown confounding variable which led us to reject this study. A subsequent investigation of washing red cells showed that the washing effect may be due to a plasma factor likely to be more than 5kDa MW which can be removed from red cells by washing with buffers. When the cells are washed, the concentration of cPLA(2) in the red cell, as measured by ELISA, significantly increases. We advise against washing the red cell in any study that involves measuring cPLA(2) by ELISA.

Prevalence and course of schizophrenia in a Chinese rural area

OBJECTIVE

To assess the characteristics and factors affecting course of schizophrenia in a Chinese rural area.

METHOD

An epidemiological investigation was conducted to identify all the patients with schizophrenia among 149 231 people in Xinjin County, Chengdu.

RESULTS

The total prevalence of schizophrenia was 4.13 per 1000 population. Males had an earlier mean age of onset (29.6 years) than females (32.3 years). Duration of illness before treatment and the total duration of illness were found to be significantly associated with level of remission. The status of treatment, family economy, housing, and families' care of patients had a significant effect on the clinical course of the illness.

CONCLUSIONS

Duration of illness before treatment may be an important predictor of course in schizophrenia. Early treatment for the patients may produce higher level of improvement in prognosis. Education intervention and community-based service are urgent priorities for these patients.

Schizophrenia spectrum disorders and eye tracking dysfunction in singleton and multiplex schizophrenia families

One line of research which is helping to unravel the genetic susceptibility to schizophrenia (SZ) is the analysis of eye tracking dysfunction (ETD), a quantifiable phenotypic marker. To investigate if such a biological marker is also present in singleton schizophrenia families, we examined eye tracking in members of singleton families (N=53) and compared it to members of multiplex (N=76) and nonpsychiatric families (N=71) using high resolution infrared oculography. The prevalence of ETD defined by gain values (eye/target velocity) and saccadic frequencies during smooth pursuit at 15 degrees /s did not differ between multiplex and singleton families in either the schizophrenic index patients or their relatives, but was significantly different from nonpsychotic families. ETD rate was higher in those relatives with compared to those without a diagnosis of a schizophrenia spectrum disorder. In relatives with a spectrum disorder, ETD appeared to be associated with traits for "sensitivity" and "suspiciousness". In the group of relatives from singleton families without a schizophrenia spectrum disorder, we still found a higher prevalence of ETD than in nonpsychotic families. Our results suggest that eye tracking dysfunction is a very sensitive biological marker for the vulnerability to schizophrenia, even in those cases where no psychopathological symptoms or signs are obvious. ETD in schizophrenia is suggested to serve as a neurophysiological type model, indicating a perception deficit.

Age-at-onset and schizophrenia: reversed gender effect

OBJECTIVE

This study seeks an explanation for reversed gender effect on age-at-onset (AAO) in schizophrenia. The hypothesis is older AAO in males would be detected in a sample where higher infant mortality (IMR) prevailed.

METHOD

Case records of International Classification of Diseases-10 (ICD-10) schizophrenia patients from two states (n=70 each) with an IMR of 13 and 67 per thousand were reviewed and AAO was obtained by using the recorded age and duration of illness.

RESULTS

In the sample from the state with lower IMR, AAO did not differ between the two sexes. However, men had older AAO than women in the state with fivefold higher IMR.

CONCLUSION

Gender differences in AAO may be a function of perinatal complications. In places where infants with perinatal complications are less likely to survive, hence high IMR, a small group of potentially youngest AAO schizophrenic males may be eliminated thus changing the gender effect on AAO.

Duration of pretreatment phases in schizophrenia: women and men

OBJECTIVE

To determine the relative duration of the prepsychotic prodrome and the period of untreated psychosis in women and men with schizophrenia.

METHOD

From a larger study population, we selected 27 women and 34 men treated at 1 facility. To determine the time of first behavioural change and the time of first psychotic symptoms, we administered the Interview for the Retrospective Assessment of the Onset of Schizophrenia (IRAOS). Subjects' mothers were interviewed using the same instrument. Time of first treatment was determined by hospital record.

RESULTS

The first sign of behavioural disturbance occurred at approximately the same age in women and men. The prepsychotic prodrome was almost twice as long for women as for men. The duration of untreated psychosis did not differ between the 2 sexes. Substance abuse did not influence the observed difference between men and women in the duration of the prepsychotic phase. The interval between first behavioural sign and first treatment was, on average, 6 years for men and 9 years for women.

CONCLUSION

As-yet-unknown factors speed up the progression from nonspecific symptoms to psychosis in men or delay it in women.

Main risk factors for schizophrenia: increased familial loading and pre- and peri-natal complications antagonize the protective effect of oestrogen in women

Women fall ill with schizophrenia 3 to 4 years later than men. The neurobiological mechanism, explaining the delay of onset in women until menopause, is presumably due to a sensitivity reducing effect of oestrogen on central d(2) receptors, as we have previously shown in animal experiments and in a controlled clinical study. The gender difference in age at onset seems to disappear in familial cases with schizophrenia, but it increases to highly significant values of 5 years or more in isolated cases according to a recent study by Albus and Maier (Schizophrenia Research 18:51-57, 1995). We tried to replicate these findings and to test the hypothesis of a functional antagonism between genetic predisposition to illness and the protective effect of oestrogen in a population-based sample of 232 first illness episodes of schizophrenia. In women with at least one first-degree relative suffering from schizophrenia, age at onset defined by first psychotic symptom was significantly reduced by several years and the difference with men disappeared. In sporadic female cases (no mental disorder in first-degree relatives) the age at onset was slightly increased compared with the total sample, which was in accordance with our hypothesis. In men with familial schizophrenia, but without a protective agent like oestrogen, the age at onset was only slightly and non-significantly reduced compared with the total group and with sporadic cases. This was in line with Albus and Maier and with our hypothesis that only the protective effect of oestrogen could be antagonized by a strong genetic disposition. The second main risk factor for schizophrenia is pre- and peri-natal complications. We compared men and women from our sample of first illness episodes with a history of pre- and peri-natal complications with those without a history of obstetric complications. In women the age at first psychotic symptom was markedly reduced, but due to small case numbers not significantly, compared with women without the risk factor and with the total group. Again, schizophrenic men with a history of pre- and peri-natal complications showed only a small, non-significant reduction of age at onset compared with the total and the group without the risk factor. Therefore, we concluded that the degree of genetically determined vulnerability and, presumably to a slightly lesser extent, the degree of pre- and peri-natal brain injury antagonizes the onset delaying effect of oestrogen in schizophrenia.

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.

Age at onset and outcome in schizophrenia are related to the degree of familial loading

BACKGROUND

Recent research suggests that high familial loading is associated with early onset of schizophrenia. Results concerning outcome have been controversial.

METHOD

We assessed the relationship between familial loading, age at onset and outcome in all Finnish patients with schizophrenia born between 1950 and 1969. Patients and their first-degree relatives were identified using nationwide registers. Familial loading scores were calculated for schizophrenia and for combined psychotic disorders, and patients were accordingly classified into three groups: high (n = 761), intermediate (n = 14,247), and low familial loading (n = 725). Linear mixed models and the Cox proportional hazard model were used in the analyses.

RESULTS

Onset was earliest, hospitalisation longest and risk of retirement in receipt of a disability pension highest in the group with high familial loading, with opposite extremes found in the group with low familial loading.

CONCLUSIONS

High familial loading for schizophrenia is associated with early onset and poor outcome of schizophrenia.

Differences in distribution of ages of onset in males and females with schizophrenia

An earlier age at onset of schizophrenia in men as opposed to women, has been widely reported, but hitherto, insufficient account has been taken of parameters that might confound this finding. Furthermore, few explanatory models have accounted for the differences in shape of the age-at-onset distributions in males and females with schizophrenia. A catchment area sample of 477 first contact cases with schizophrenia or related disorders was ascertained through a case register. Differences in age at onset distributions between males and females were determined, and adjustment made for potential confounding factors. The most powerful predictors of early illness-onset were poor premorbid occupational functioning, single marital status, and male sex. The earlier onset in males was robust to controlling for other parameters. The shape of the onset distribution also differed between the sexes: SKUMIX analysis revealed a two-peak distribution for males, and a three-peak distribution for females. The mean age at onset for schizophrenia is earlier in males, and the onset distribution differs between the sexes. Psychosocial variables cannot explain these findings. Possible explanations for these gender differences include males and females being differentially susceptible to subtypes of illness with different mean ages at onset; precipitating and/or ameliorating factors operating at different stages of life in males and females; and/or an X-linked susceptibility locus that determines the age at onset.

Sex difference in age at onset of schizophrenia: discrepant findings from India

Consecutive male (n=100) and female (n=100) DSM-IV schizophrenics newly registered for treatment in a large psychiatric hospital were examined with regard to age at onset of the first psychotic symptom. Age at onset of the first psychotic symptom did not differ between the sexes regardless of whether schizophrenia was diagnosed by DSM-IV or by several alternative systems. Age at onset defined by other criteria, namely age at first contact with a physician, and age at first admission for psychiatric care, also did not show any differences between the sexes. Survival analysis of subjects having a documented date of birth revealed a female preponderance at younger ages. A higher positive symptom score predicted older age at onset of the first psychotic symptom in the total sample. These findings call into question the universality of the traditional view of a younger age at onset of schizophrenia among males. Tentative neurodevelopmental and cultural explanations are presented to explain why there is no sex difference in age at onset of schizophrenia in India.