Sampling biases in studies of gender and schizophrenia

Follow-up studies of schizophrenia I: Natural history and non-psychopathological predictors of outcome

Treatment-resistant schizophrenia does not exist as a discrete entity, so separating patients who will fail to respond to traditional antipsychotics from those who will respond is impossible with 100% accuracy. However, several predictors of poor clinical outcome have emerged from recent research and knowledge of the processes that lead to poor outcome has become increasingly important with the advent of atypical antipsychotics that may be used in patients with treatment-resistant illness. Much of the variation in outcome can be understood in terms of differences in sample selection, outcome definition and stringency of the diagnostic criteria used. Failure to appreciate these mechanisms may lead to over- or underestimation of the proportion of patients with poor treatment response in clinical and research settings. The importance of factors that predict poor outcome should be judged in terms of their effect size and the degree to which alternative explanations for the association with outcome have been excluded. Although much current research is being focused on specific biological predictors, baseline demographic and illness-related factors, such as ethnic group, sex, social class, type of onset, age of onset and concurrent misuse of alcohol or drugs, have large effects on outcome. Although duration of untreated psychosis before first contact with services may independently predict poor outcome, confounding by variables that are associated with both pathways to care and clinical outcome has not been excluded.

The impact of gender and childhood abuse on age of psychosis onset, psychopathology and needs for care in psychosis patients

Gender is associated with several features of psychotic disorders, including age of illness onset, symptomatology, a higher prevalence of history of childhood sexual abuse (CSA) and needs for care. Childhood sexual abuse is associated with adverse mental health consequences but as there is a gender difference in stress reactivity, there may be a differential impact of CSA on psychopathology, age of psychosis onset and needs for care in First Episode Psychosis (FEP) patients. We hypothesized that a history of abuse would be associated with lowering of age of onset, increased symptomatology and more unmet needs in women but not men. A total of 444 FEP patients have been recruited within the context of the GET UP trial. Symptomatology has been assessed using the PANSS scale, needs for care with the CAN scale and childhood abuse with the CECA-Q scale. Childhood sexual abuse was more frequent among female patients [22.6% in women vs 11.6% in men (OR = 0.45, p < 0.01)], whereas there was no gender difference in the prevalence of childhood physical abuse (29.0% in women vs 31.7% in men). Childhood abuse was associated with higher levels of negative symptoms in both men and women, with a reduced age of onset in women only and little increase in needs for care in both men and women. Our results seem to suggest that childhood sexual abuse in female FEP patients may be linked to a more severe form of psychosis whose presentation is characterized by earlier age of onset and higher levels of negative symptoms and we can also speculate that gender-specific protective factors in women, but not in men, may be outweighed by the consequences of childhood abuse.

Sex and gender differences in schizophrenic psychoses-a critical review

Many sex and gender differences in schizophrenic psychoses have been reported, but few have been soundly replicated. A stable finding is the later age of onset in women compared to men. Gender differences in symptomatology, comorbidity, and neurocognition seem to reflect findings in the general population. There is increasing evidence for estrogens being psychoprotective in women and for hypothalamic-pituitary-gonadal dysfunction in both sexes.More methodologically sound, longitudinal, multi-domain, interdisciplinary research investigating both sex (biological) and gender (psychosocial) factors is required to better understand the different pathogenesis and etiologies of schizophrenic psychoses in women and men, thereby leading to better tailored treatments and improved outcomes.

Early treatment resistance in a Latin-American cohort of patients with schizophrenia

BACKGROUND

Failure to respond to antipsychotic medication in schizophrenia is a common clinical scenario with significant morbidity. Recent studies have highlighted that many patients present treatment-resistance from disease onset. We here present an analysis of clozapine prescription patterns, used as a real-world proxy marker for treatment-resistance, in a cohort of 1195 patients with schizophrenia from a Latin-American cohort, to explore the timing of emergence of treatment resistance and possible subgroup differences.

METHODS

Survival analysis from national databases of clozapine monitoring system, national disease notification registers, and discharges from an early intervention ward.

RESULTS

Echoing previous studies, we found that around 1 in 5 patients diagnosed with schizophrenia were eventually prescribed clozapine, with an over-representation of males and those with a younger onset of psychosis. The annual probability of being prescribed clozapine was highest within the first year (probability of 0.11, 95% confidence interval of 0.093-0.13), compared to 0.018 (0.012-0.024) between years 1 and 5, and 0.006 (0-0.019) after 5years. Age at psychosis onset, gender, dose of clozapine used, and compliance with hematological monitoring at 12months, was not related to the onset of treatment resistance. A similar pattern was observed in a subgroup of 230 patients discharged from an early intervention ward with a diagnosis of non-affective first episode of psychosis.

CONCLUSIONS

Our results highlight that treatment resistance is frequently present from the onset of psychosis. Future studies will shed light on the possible different clinical and neurobiological characteristics of this subtype of psychosis.

Systematic review and collaborative recalculation of 133,693 incident cases of schizophrenia

BACKGROUND

This systematic review and collaborative recalculation was set up to recalculate schizophrenia incidence rates from previously published studies by age and sex.

METHOD

PubMed, EMBASE and PsycINFO databases were searched (January 1950 to December 2009) for schizophrenia incidence studies. Numerator and population data were extracted by age, sex and, if possible, study period. Original data were requested from the authors to calculate age- and sex-specific incidence rates. Incidence rate ratios (IRRs) with their 95% confidence intervals (CIs) were computed by age and sex from negative binomial regression models.

RESULTS

Forty-three independent samples met inclusion criteria, yielding 133 693 incident cases of schizophrenia for analysis. Men had a 1.15-fold (95% CI 1.00-1.31) greater risk of schizophrenia than women. In men, incidence peaked at age 20-29 years (median rate 4.15/10,000 person-years, IRR 2.61, 95% CI 1.74-3.92). In women, incidence peaked at age 20-29 (median rate 1.71/10,000 person-years, IRR 2.34, 95% CI 1.66-3.28) and 30-39 years (median rate 1.24/10,000 person-years, IRR 2.25, 95% CI 1.55-3.28). This peak was followed by an age-incidence decline up to age 60 years that was stronger in men than in women (χ² = 57.90, p < 0.001). The relative risk of schizophrenia was greater in men up to age 39 years and this reversed to a greater relative risk in women over the age groups 50-70 years. No evidence for a second incidence peak in middle-aged women was found.

CONCLUSIONS

Robust sex differences exist in the distribution of schizophrenia risk across the age span, suggesting differential susceptibility to schizophrenia for men and women at different stages of life.

Gender differences in cognitive function of patients with chronic schizophrenia

Schizophrenic patients have cognitive impairments, but gender differences in these cognitive deficits have had limited study. This study assessed cognitive functioning in 471 subjects including 122 male and 78 female schizophrenic patients and 141 male and 130 female healthy controls. We found that immediate memory, language, delayed memory and total RBANS scores were significantly decreased in schizophrenia compared with healthy controls for both genders. Male patients had significant lower immediate memory, delayed memory and total RBANS scores than female patients, and healthy controls showed a similar gender difference. The RBANS showed modest correlations with PANSS scores, duration of illness and antipsychotic dose (chlorpromazine equivalents). Almost all RBANS scores in the schizophrenics and healthy controls showed significant positive correlations with education. Thus, patients of both sexes with schizophrenia experienced more deteriorated performance than healthy controls on cognitive domains of immediate memory, language and delayed memory. Furthermore, male schizophrenic patients had more serious cognitive deficits than female patients in immediate and delayed memory, but not in language, visuospatial and attention indices.

Sex steroids and schizophrenia

The peak in incidence for schizophrenia is during late adolescence for both sexes, but within this time frame the peak is both earlier and steeper for males. Additionally, women have a second peak in incidence following menopause. Two meta-analyses have reported that men have an overall ∼40% greater chance of developing schizophrenia than do women (Aleman et al., 2003; McGrath et al., 2004). These and other findings have led to the suggestion that ovarian hormones may be protective against schizophrenia. Less explored is the potential role of testosterone in schizophrenia, although disruptions in steroid levels have also been reported in men with the illness. The relationship between increased gonadal hormone release per se and peri-adolescent vulnerability for psychiatric illness is difficult to tease apart from other potentially contributory factors in clinical studies, as adolescence is a turbulent period characterized by many social and biological changes. Despite the obvious opportunity provided by animal research, surprisingly little basic science effort has been devoted to this important issue. On the other hand, the animal work offers an understanding of the many ways in which gonadal steroids exert a powerful impact on the brain, both shaping its development and modifying its function during adulthood. Recently, investigators using preclinical models have described a greater male vulnerability to neurodevelopmental insults that are associated with schizophrenia; such studies may provide clinically relevant insights into the role of gonadal steroids in psychiatric illness.

Sex differences in neuropsychological functioning among schizophrenia patients

OBJECTIVES

Evidence from the literature addressing sex differences in cognition in schizophrenia remains equivocal, with some researchers suggesting that male schizophrenia patients are more impaired than female subjects, while others report no significant sex differences in cognitive functioning. The aim of the present study was to investigate whether the differential pattern of cognitive performance observed in healthy men and women is preserved in male and female schizophrenia patients.

METHOD

Ninety-six schizophrenia patients (56 men) were compared with 62 age- and gender-ratio matched healthy controls (31 men), on a battery of neuropsychological tests that assessed basic cognitive abilities: attention, working memory, abstraction, inhibition, fluency, verbal learning and memory, visual memory, visuospatial skills, and psychomotor speed.

RESULTS

As a group, schizophrenia patients were significantly impaired in each of the cognitive domains assessed, with the exception of psychomotor speed. The effect of sex was significant for verbal learning and memory, wherein women outperformed men. No significant group x sex interactions were found in any cognitive domains, indicating that the female advantage typically observed in verbal learning and memory remained the same in the schizophrenia patients.

CONCLUSION

The degree of cognitive impairment is the same for male and female schizophrenia patients. Those sex differences found among the patients were typical of the healthy population as well. Therefore, differential decrements in basic cognitive domains do not appear to account for the favourable course of schizophrenia in women relative to men.

The developmental pathways to schizophrenia: Potential moderating effects of stress

The observations of family members as well as the results of past research suggest that a variety of developmental pathways can precede the onset of schizophrenia in early adulthood. In this article, we describe recent findings from our research on the childhood precursors of schizophrenia. Taken together, the results indicate that childhood behavioral, emotional, and motoric dysfunction occur at a higher rate in preschizophrenia subjects when compared to control subjects. Further, there are developmental changes as well as significant variability among schizophrenia patients in the nature and severity of childhood impairment. Drawing on the prevailing diathesis-stress model, we explore the moderating role that stress exposure and reactivity may play in the expression of the organic diathesis for schizophrenia. Specifically, we consider the role of the biological stress response in the production of developmental changes and individual differences in the pathways to schizophrenia. Given extant models of dopamine involvement in the neuropathology of schizophrenia, stress-induced Cortisol release may alter the expression of subcortical abnormalities in dopamine neurotransmission. Thus, we present a neural mechanism for the hypothesized behavioral sensitivity to stress exposure in schizophrenia, and explore the capacity of the model to account for the changing behavioral manifestations of vulnerability.

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.

Perception of burden by caregivers of patients with schizophrenia

BACKGROUND

There is a dearth of studies assessing the burden of caregivers of patients with schizophrenia and illness-related variables such as age, sex, duration of illness, domicile, martial status, education, employment and previous hospitalization.

AIM

The study was conducted to measure the perception of burden by caregivers of patients with schizophrenia and its correlation with nine factors on the Burden Assessment Schedule (BAS) related to spouse, physical and mental health, external support, caregiver's routines, support to patient, responsibility-taking, other relatives, patient's behaviour and caregiver's strategy.

METHODS

Using BAS, we assessed the burden in a sample of caregivers of 34 patients with schizophrenia taken from the OPD of the Institute of Mental Health and Hospital, Agra.

RESULTS

A low positive correlation was found between urban domicile and support of the patient; of domicile Agra and effect on other relations; and domicile Agra and effect on the caregiver's routine. There was a low positive correlation between age less than 30 years and the physical and mental health of the caregiver, and with taking responsibility. The t test for population correlation was significant up to 5% probability level (p<0.05) for correlation between urban domicile and support of the patient; between domicile Agra and effect on other relations; between domicile Agra and the effect on the caregiver's routine; between age less than 30 years and the physical and mental health of the caregiver; and between age less than 30 years and taking responsibility.

CONCLUSION

Further studies in this field are required including one with a non-linear correlation analytic design.

Age of menarche and schizophrenia onset in women

OBJECTIVE

The "estrogen hypothesis" posits that this hormone serves as a protective factor in the development of schizophrenia. If true, then it is expected that the earlier the age of menarche, the later the onset of schizophrenia (as has been reported by some investigators). This study attempts to replicate this relationship in a sample of women with schizophrenia and schizoaffective disorder.

METHOD

Self-report menarche age, clinical status, and onset of disorder were collected in a sample of 68 women (55 diagnosed with schizophrenia and 13 with schizoaffective disorder).

RESULTS

Menarche age and schizophrenia onset were not negatively correlated as would be predicted by the estrogen hypothesis. Two clinical measures, however, did correlate with age of menarche as predicted. Higher negative symptom scores (total SANS) and greater functional impairment (lower GAF) were reported in subjects who reported a later age at menarche.

CONCLUSION

This study suggests that an earlier age at menarche might predict improved clinical outcome after schizophrenia onset (in support of the estrogen hypothesis). Our data, however, do not support Cohen et al.'s findings regarding the relationship between age at menarche, and the timing of the onset of the disorder. Further investigations regarding the relationship between estrogen and schizophrenia development in women are needed. It is suggested that other developmental factors, both biological and psychosocial, might play a crucial role in both the age at onset and the outcome of the disorder in women.

Sex differences in symptoms of psychosis in a non-selected, general population sample

BACKGROUND

Little is known about sex differences in psychosis beyond the borders of clinical disorder.

METHODS

A general population sample of 7,076 subjects was assessed using the Composite International Diagnostic Interview, in order to explore sex differences in the prevalence of any positive and negative symptoms of psychosis, and to examine to what degree any differences could be explained by differences in level of affective symptoms.

RESULTS

Male sex was associated with higher prevalence of negative symptoms (OR = 1.6, 95% CI = 1.0, 2.5), independent of differences in affective symptoms and presence of DSM-III-R psychotic disorder. Women had higher rates of positive psychotic experiences (OR = 0.8, 95% CI = 0.7, 0.9), but this difference disappeared after adjustment for depressive symptoms (adjusted OR = 1.2, 95% CI = 0.9, 1.5).

CONCLUSION

The sex differences in psychopathology that are seen in schizophrenia are expressed beyond the clinical phenotype, suggesting sex-dependent continuous and normal variation of several psychosis dimensions. The higher rates of positive psychotic experiences seen in women may be secondary to differences in the rate of affective symptoms.

Sexual dimorphism in minor physical anomalies in schizophrenic patients and normal controls

The aim of the current study was to investigate the gender effecton minor physical anomalies (MPA) in schizophrenic patients and normal controls. Seventy-six schizophrenic patients (43 males and 33 females) and 82 normal control subjects (42 males and 40 females) were examined for MPA using a modified version of the Waldrop Physical Anomaly Scale. Men tended to be more stigmatized with MPA than women both in normal subjects and in schizophrenics (with this difference slightly expanding in schizophrenics). In both genders schizophrenic patients were significantly more likely to have MPA than normal controls, but the difference tended to be more pronounced in males. There was a tendency towards sex-related predilection for the increase of MPA in schizophrenics in terms of individual anomalies and topographic regions affected. Among schizophrenics, genders showed a somewhat opposite topography of MPA stigmatization, with relatively more pronounced peripheral dysmorphy in males and craniofacial dysmorphy in females. These data suggest greater vulnerability of the male fetus to endogenous or exogenous factors and different susceptibilities to developmental adversities in male and female schizophrenics. This finding is in accord with the increasing evidence that sex differences in the epidemiology of schizophrenia may be broader and more fundamental than previously thought.

Sex differences in clinical response to olanzapine compared with haloperidol

There is current disagreement over whether men and women respond differently to typical or atypical antipsychotic medications. This study reanalyzed a large international clinical trial of olanzapine (Olz) compared with haloperidol (Hal) to test for sex differences in treatment response, controlling for illness chronicity and menopausal status. We hypothesized that women would show a greater response to either medication than men, particularly among first admission, premenopausal women. DSM-III-R schizophrenia inpatients (700 women and 1295 men) were randomly assigned to a 6-week trial of Olz vs. Hal. Longitudinal random effect models were used to test for interactions of sex with medication, chronicity and menopausal status on treatment response. Findings showed that women on olanzapine had a greater drop in overall symptomatology by week 4 than any other group, and their level of symptomatology remained lower throughout the 6-week trial. The sex differences in treatment response in olanzapine compared with haloperidol were, in part, dependent on chronicity and, in women, menopausal status. That is, first episode women on haloperidol exhibited an increase in symptomatology over the 6-week trial compared to their male counterparts, while multiply hospitalized women had a better treatment response on haloperidol than their male counterparts. Women on olanzapine had a significantly better treatment response than men, regardless of chronicity. Finally, premenopausal women had a significantly better treatment response than postmenopausal women, regardless of treatment and chronicity.

Dopamine receptors in the brains of schizophrenia patients: a meta-analysis of the findings

Controversy surrounds the question of whether there are dopamine (DA) receptor abnormalities in the brains of schizophrenia patients; in particular, whether DA receptors of the D2 family are elevated in density. Methodological factors and sample characteristics have been postulated to account for differences in study outcome, but there has been no systematic analysis of the contribution of these factors to study effect sizes. This meta-analysis of the research findings sought to determine the influence of methodologic factors and sample characteristics on the magnitude of diagnostic group differences in DA D2 density (Bmax) and affinity (Kd). The analysis suggests at least moderate effects, such that schizophrenia patients show an elevation in both values when compared to controls. These effects are amplified in medicated patients, but not solely attributable to antipsychotics. The group differences in DA D2 receptor density and affinity increase with age among nonmedicated patients. The use of a butyrophenone ligand also yields larger effects. It is concluded that a subgroup of schizophrenia patients manifests increased DA D2 receptor density and decreased receptor affinity. In the absence of medication, these changes may become more pronounced with age. Differences in study outcome are also partially due to methodologic factors, including the ligand.

Psychosocial characteristics and needs of mothers with psychotic disorders

BACKGROUND

It is not known whether mothers with psychotic disorders are clinically and socially distinct from women with psychoses who have not had children.

AIMS

To determine the proportion of mothers in an epidemiologically representative population of women with psychotic disorders, to examine the factors associated with having children, and to examine the factors associated with having children 'looked after' by social services.

METHOD

Descriptive analysis and two case-control studies.

RESULTS

Sixty-three per cent of women with psychotic disorders were mothers. There were no clinical differences between women with or without children, but mothers were more likely to be older and live in unsupported accommodation. Having had a 'looked after' child was associated with Mental Health Act detention, younger age, a forensic history and being Black African.

CONCLUSION

Many women with psychoses are mothers. Mothers with psychoses are as disabled and have as many needs as women with psychoses without children.

Misunderstanding analysis of covariance

Despite numerous technical treatments in many venues, analysis of covariance (ANCOVA) remains a widely misused approach to dealing with substantive group differences on potential covariates, particularly in psychopathology research. Published articles reach unfounded conclusions, and some statistics texts neglect the issue. The problem with ANCOVA in such cases is reviewed. In many cases, there is no means of achieving the superficially appealing goal of "correcting" or "controlling for" real group differences on a potential covariate. In hopes of curtailing misuse of ANCOVA and promoting appropriate use, a nontechnical discussion is provided, emphasizing a substantive confound rarely articulated in textbooks and other general presentations, to complement the mathematical critiques already available. Some alternatives are discussed for contexts in which ANCOVA is inappropriate or questionable.

The ascertainment of multiplex schizophrenia pedigrees from Daghestan genetic isolates (Northern Caucasus, Russia)

This article describes the preliminary ascertainment of multiplex schizophrenia pedigrees from the isolated mountain region of Daghestan (Northern Caucasus, Russia). Daghestan has a population of two million people and contains 26 aboriginal ethnic groups. Many of the ethnic groups reside in remote mountain villages that can be classified as 'primary isolates'. Prolonged reproductive isolation and severe environmental conditions in the highlands have created diverse, genetically isolated ethnic populations in Daghestan. A number of the isolates in this region contain large extended multiplex schizophrenia pedigrees that are ideal for genetic analyses. During summer expeditions of 1996 and 1997, 14 separate large multiplex schizophrenia pedigrees were ascertained from 14 different mountain villages. Of the 14 kindreds, one had 50 schizophrenic cases available for ascertainment, one had 32, and another had 24. Seven of the remaining pedigrees had between 11 and 23 living cases. Within the kindreds, the number of males with chronic schizophrenia was at least twice that of females. The average age of onset of schizophrenia is 21.2 years for offspring of consanguineous marriages and 17.4 years for offspring of nonconsanguineous marriages (P = 0.033). Although the pedigrees ascertained from the remote mountain villages may not be representative of the general population, they are unique kindreds for mapping schizophrenia susceptibility genes.

Full recovery from schizophrenia: the prognostic role of premorbid adjustment, symptoms at first admission, precipitating events and gender

A number of long-term studies of course and outcome in schizophrenia report that about a fourth of the cases show good clinical and social recovery. However, very few studies have been carried out examining the main characteristics of schizophrenia patients who have fully recovered according to a strict definition of 'full recovery'. The purpose of the present study was, therefore, to compare a group of 17 fully recovered schizophrenia patients (Group A) with a group of 33 patients (Group B) with current symptoms of schizophrenia on several prognostic factors that have been associated with a good outcome. These clinical groups were matched groupwise with a similar mean on two variables: age range at onset of illness and age at time of interview. Duration of illness (length of time from age of onset of illness to time of assessment) was 22.4 years in group A and 21 years in group B. Mean GAS scores were 72.2 and 46.5, respectively. Positive symptoms (delusions and disorganized behavior) at admission predicted an unfavorable outcome. The results confirmed the prognostic significance of several clinical and demographic factors. However, a good premorbid adjustment did not show significant predictive power, but showed substantial association in the predicted direction. In addition, a clear sex difference was found: women report a significantly better premorbid functioning and demonstrate a more favorable psychosocial functioning than men.

Vocational interests and career indecision among psychosis-prone college students

This study investigated the relationship between scores on scales that purport to measure psychosis-proneness and scores on vocational interests, identity, and differentiation scales in a sample of 233 college students who completed the Perceptual Aberration and Magical Ideation scales, the Strong Campbell Interest Inventory, and the Career Decision Scale. The present findings are consistent with prior work indicating a sex-related association of scores on measures of psychosis-proneness and vocational interests. A positive correlation between scores on vocational indecision and measures of psychosis-proneness was also found, suggesting that both men and women who score high on psychosis-proneness find it difficult to formulate long-term career goals. Finally, there was no significant correlation between scores on measures of psychosis-proneness and Holland's Vocational Differentiation Index. Present results are discussed in light of previously reported sex differences among psychosis-prone adults and diagnosed schizophrenics. The implications of the findings for vocational counselors are also addressed.

First-onset schizophrenia in the community: relationship of urbanization with onset, early manifestations and typology

As part of a World Health Organization collaborative study in 12 centres in developing and developed countries within defined urban and rural catchment areas with populations of 348,786 and 103,865, respectively, a total of 155 and 54 cases of first-onset schizophrenia, respectively, were identified over a 24-month period by a comprehensive and active recruitment of all cases. Approximately 50% of the subjects in both cohorts were in the age range of 15-24 years. There was a preponderance of males in the younger age group and of females in the older age group. The majority of cases had no family history and had shown good adjustment in childhood and adolescence. The onset was much more frequently acute and much less often insidious in our samples and (more so in the rural cohort), compared to the figure for all developed countries' sites. With regard to early manifestations of the disorder, there was a much higher incidence of loss of interest in appearance and cleanliness, being irritable and angry without reason, and loss of appetite, sleep or interest in sex in both of our samples, and of being excited or overactive for days or weeks in our rural cohort than in the developed countries' centres as a whole. On the other hand, claiming impossible things, behaving as if hearing voices and feeling persecuted, harmed or bewitched were much less frequent in our rural cohort than in the urban cohort or the developed countries' centres as a whole. With regard to the clinical diagnosis of schizophrenia, paranoid, hebephrenic/disorganized and residual types were under-represented in our samples (more so in the rural sample), and catatonic type and acute schizophrenic episode were over-represented compared to the developed countries' centres. Moreover, the proportion of subjects of CATEGO class S+ was lower in our samples. With regard to onset, early manifestations and clinical subtypes of schizophrenia, our rural cohort deviated most from developed countries' centres as a whole, with our urban sample falling in between, thus indicating the role of socio-cultural factors in general, and urbanization in particular, in these variables in schizophrenia.

Are there gender differences in neuropsychological performance in patients with first-episode schizophrenia?

To investigate gender differences in neuropsychological (NP) functioning in first episode (FE) schizophrenia, consecutively recruited patients with FE schizophrenia (37 males, 29 females) and a subsample of these patients (20 males, 20 females), individually matched for gender, age, and education to healthy controls (20 males, 20 females) were compared on a battery of standardized neuropsychological tests. Women performed better than men in tests of verbal memory and learning, and men performed better than women in spatial organization. However, no differences were present between schizophrenic patients and controls, except that male and female schizophrenic patients showed the most pronounced impairment in visual motor processing, attention and verbal memory and learning. Our data suggest that gender does not appear markedly to modify the cognitive impairment characteristic of schizophrenia. However, they underline the necessity of controlling confounding factors on NP performance such as gender and education.

Sex differences in neuropsychological function in non-psychotic relatives of schizophrenic probands

Some recent studies suggest that men with schizophrenia may have greater neuropsychological deficits than women. It is not known, however, whether similar sex differences may be present in biological relatives of schizophrenic patients. We evaluated neuropsychological functioning of 54 relatives of schizophrenic patients and 72 normal volunteers. It was hypothesized that, if sex differences were present, they would be accounted for largely by deficits in male relatives. We were particularly interested in three neuropsychological functions that we previously identified as putative neuropsychological vulnerability indicators for schizophrenia: (1) abstraction/executive function; (2) verbal memory; and (3) auditory attention. There were significant group x sex interactions for verbal memory and motor function, and trends toward significant interactions for auditory attention and mental control/encoding. However, with the exception of motor function, it was the female relatives who accounted for most of the impairment. A speculative explanation for the findings is that women may have a higher threshold than men for developing schizophrenia. If so, female relatives might be able to withstand greater impairments than men before developing psychotic symptoms. Consequently, in a sample that was limited to non-psychotic relatives--as in the present study--there could be over-representation of both less impaired men and more impaired women. Alternative explanations and limitations of the study are also discussed.

Explaining sex differences in course and outcome in the functional psychoses

We addressed the following three questions: (i) are there sex differences in outcome in the functional psychoses?, (ii) what is their effect size, and which variables mediate the effect of sex on outcome?, (iii) is the effect of sex diagnosis-specific? In a prospective study of 166 patients with recent onset psychosis, we established that 4-year outcome was more favourable for women. Female patients more often had a remitting illness course (OR = 3.0; 95% CI: 1.5-5.9), were living independently 14% (4-24%) more of the time, had less evidence of negative symptoms over the follow-up period (OR = 0.3; 0.2-0.7) and were more likely to be employed at follow-up (3.6; 1.8-7.6). The findings did not appear diagnosis-specific, although the sample size was small to test for interaction with diagnostic category. Baseline occupational and social adjustment, clinical expression of illness and age and type of onset explained up to 60% of the sex effect. The processes underlying these factors mediate the effect of sex on outcome.

Childhood-onset schizophrenia: the severity of premorbid course

OBJECTIVE

To review the premorbid histories of 23 children meeting DSM-III-R criteria for schizophrenia with onset before age 12 years and to compare these with childhood data of later-onset schizophrenics.

METHOD

Premorbid features up to 1 year before onset of first psychotic symptoms were rated from hospital and clinic records, clinical interviews, rating scales, and tests.

RESULTS

In keeping with previous studies, specific developmental disabilities and transient early symptoms of autism, particularly motor stereotypies, were common. Comparison with the childhood of later-onset schizophrenics showed greater delay in language development, and more premorbid speech and language disorders, learning disorders, and disruptive behavior disorders. (Sixty percent had received or were estimated to meet criteria for one or more clinical diagnoses.)

CONCLUSIONS

Childhood-onset schizophrenia may represent a more malignant form of the disorder, although selection and ascertainment bias cannot be ruled out. The presence of prepsychotic language difficulties focuses attention on the importance of early temporal and frontal lobe development; early transient motor stereotypies suggest developmental basal ganglia abnormalities and extend previous findings seen in the childhood of later-onset patients.

Memory and social skill in schizophrenia: the role of gender

The relationship between social skill and memory was examined in a group of patients with schizophrenia and schizoaffective disorder. There were few or no differences between male and female patients in history of the illness, symptomatology, memory, and other cognitive factors, or social skill. Despite the absence of differences, impaired memory was related to poorer social skills for the women, but not the men. Reanalysis of data on social skill and memory from an earlier study (Mueser et al., 1991) revealed a similar pattern of results. The findings suggest that the contribution of cognitive factors to impaired social competence in schizophrenia may differ in men and women. Alternatively, the results may reflect sampling bias, whereby more severely ill women are studied than men, relative to their respective populations.