Fertility in schizophrenia: results from a contemporary US cohort

Psychotic disorders and parenting - the relevance of patients' children for general adult psychiatric services

Patients with psychotic disorders are often assumed to be sub-fertile, and when patients do have children, any child care concerns are usually passed on to social services. The children of patients with psychotic disorders may not, therefore, be of major concern to the responsible medical officer, and community mental health services have not been developed with families in mind. Routine statistics on psychiatric patient episodes do not include information on patients' children – a question covering this issue was included in the pilot draft of the Mental Health Minimum Data Set (approved for England by the Department of Health in September 1999), but was dropped because clinical professionals were reluctant to record this information, as they did not consider it relevant in this context (personal communication, G. Glover, 2000).

Neuropsychiatric Features in Primary Mitochondrial Disease

Mitochondrial diseases are a clinically heterogeneous group of disorders that ultimately result from dysfunction of the mitochondrial respiratory chain. There is some evidence to suggest that mitochondrial dysfunction plays a role in neuropsychiatric illness; however, the data are inconclusive. This article summarizes the available literature published in the area of neuropsychiatric manifestations in both children and adults with primary mitochondrial disease, with a focus on autism spectrum disorder in children and mood disorders and schizophrenia in adults.

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.

Pre-morbid fertility in psychosis: findings from the AESOP first episode study

Individuals with psychotic illnesses are known to have a reduced fertility. It is unclear whether this is due to biological or social factors. Most fertility studies have been conducted in chronic schizophrenia, where confounders like medication and hospitalisation make this difficult to elicit. A less severe reduction of fertility has been observed in some ethnic minorities, but results are inconsistent. We sought to investigate pre-morbid fertility in an ethnically diverse sample of individuals with first-onset psychosis. Data were derived from 515 people with a first psychotic episode (FEP) and 383 controls. We made case-control comparisons of differences in the proportion of those with children (fertility rates) and mean number of children (MNC). Analyses were then stratified by diagnosis, gender and ethnicity, and adjusted for potential confounders. We found that FEP showed a reduced fertility rate (age-adjusted OR of having children 0.47 [95% CI=0.39, 0.56]), irrespective of diagnosis, and there was little evidence of confounding by gender, ethnicity, religious background, education level, or history of past relationships (fully adjusted OR=0.55, 95% CI=0.37, 0.80). Women had a somewhat greater reduction in fertility rates than men (Men: age-adjusted OR 0.61 [95% CI 0.42, 0.89]; Women: age-adjusted OR 0.46 [95% CI 0.31, 0.69]) and we could not find any evidence of ethnic differences in the degree of fertility reduction. FEP who had previously experienced a stable relationship had an MNC that was comparable to that of the general population and had a later onset of illness. This is the largest case-control study to date to investigate fertility in first-onset psychosis. Our data suggests that fertility is affected, even prior to the onset of a psychotic illness, and there are likely to be biological and environmental factors involved, but the former seem to have a stronger influence.

Reduced Fertility and Fecundity among Patients with Bipolar I Disorder and Schizophrenia in Egypt

OBJECTIVE

To evaluate reproduction among patients with bipolar I disorder (BP1) or schizophrenia (SZ) in Egypt.

METHODS

BP1 patients (n=113) were compared with community based, demographically balanced controls (n=124) and SZ patients (n=79, DSM-IV). All participants were evaluated using structured interviews and corroborative data were obtained from relatives. Standard indices of procreation were included in multivariate analyses that incorporated key demographic variables.

RESULTS

Control individuals were significantly more likely to have children than BP1 or SZ patients (controls 46.8%, BP1 15.9%, SZ 17.7%), but the BP1-SZ differences were non-significant. The average number of children for BP1 patients (0.37±0.9) and SZ patients (0.38±0.9) was significantly lower than for controls (1.04±1.48) (BP1 vs controls, p<0.001; SZ vs controls, p<0.001). The frequency of marriages among BP1 patients was nominally higher than the SZ group, but was significantly lower than controls (BP1: 31.9% SZ: 27.8% control: 57.3%). Even among married individuals, BP1 (but not SZ) patients were childless more often than controls (p=0.001). The marital fertility, i.e., the average number of children among patients with conjugal relationships for controls (1.8±1.57) was significantly higher than BP1 patients (1.14±1.31, p=0.02), but not significantly different from SZ patients (1.36±1.32, p=0.2).

CONCLUSION

Selected reproductive measures are significantly and substantially reduced among Egyptian BP1 patients. The reproductive indices are similar among BP1 and SZ patients, suggesting a role for general illness related variables. Regardless of the cause/s, the impairment constitutes important, under-investigated disability.

Reproductive patterns in psychotic patients

CONTEXT

Longitudinal epidemiological studies have shown worse outcomes in patients with psychotic disorder than in the general population. The reproductive pattern may be seen as a measure of outcome following psychotic disorder onset, and it may be measured as the rate of child births where the rate is a proxy measure of well-being.

OBJECTIVE

To examine reproductive patterns following psychotic disorder onset by comparing the fertility rates of patients with schizophrenia and bipolar disorder with those of other psychiatric patients and the general population, taking into account parental status at disease-onset, time since onset, and the possible effect of abortions-rates.

METHODS

A prospective register-based cohort study drawing on the entire Danish population born after 1950. Incidence Rate Ratios (IRRs) of fertility were analysed using survival analysis.

RESULTS

Compared with the general population, the lowest first-child fertility rate was found among men (IRR=0.10) and women (IRR=0.18) with schizophrenia. In comparison, bipolar male patients had an IRR=0.32 and female patients an IRR=0.36, while male unipolar patients had an IRR=0.46 and female patients an IRR=0.57. In the group with other psychiatric disorders men had an IRR=0.51 and women an IRR=0.70.

CONCLUSIONS

The results of the present study show a selection process where persons with more severe disorders are less likely to become parents. The reduced fertility was strongly influenced by the time since psychiatric disorder onset; thus, the longer the time since onset, the higher the fertility.

Time-to-pregnancy and risk of schizophrenia

Schizophrenia has been linked to advanced paternal age, but the explanation is unknown. We questioned whether the incidence of schizophrenia would be related to male reproductive capacity, as reflected in the time taken to conceive. We measured the incidence of schizophrenia in relation to time to conception in a sub-group of 12,269 in the Jerusalem cohort whose mothers, interviewed post-partum, reported that the pregnancy had been intended. Compared with those conceived in less than 3 months, the unadjusted relative risks (RR) of schizophrenia associated with conception-waits of 3-5, 6-11 and 12+ months were 1.10 (95% confidence interval, 0.62-1.94), 1.41 (0.79-2.52) and 1.88 (1.05-3.37) with p for trend=0.035. This trend was attenuated somewhat by adjusting for paternal age, and was observed more strongly in offspring of fathers aged 30+ (p=.010). These findings suggest that factors associated with fecundability, either male or female, may contribute to the risk of schizophrenia.

Lifetime reproductive output over two generations in patients with psychosis and their unaffected siblings: the Uppsala 1915-1929 Birth Cohort Multigenerational Study

BACKGROUND

Schizophrenic patients have fewer offspring than the general population but it is unclear whether (i) this persists for more than one generation, (ii) the reduced fertility is compensated by increased fertility in unaffected relatives, (iii) sociodemographic factors confound or interact with the association, and (iv) patients with affective psychosis have a similar fertility disadvantage. This study measured biological fitness over two generations in patients with schizophrenia or affective psychosis, and their unaffected siblings.

METHOD

We conducted a historical cohort study using a Swedish birth cohort of 12 168 individuals born 1915-1929 and followed up until 2002. We compared biological fitness over two generations in patients with schizophrenia (n=58) or affective psychosis (n=153), and their unaffected siblings, with the population, adjusting for a range of sociodemographic variables from throughout the lifespan.

RESULTS

Patients with schizophrenia had fewer children [fertility ratio (FR) 0.42, 95% confidence interval (CI) 0.29-0.61] and grandchildren (FR 0.51, 95% CI 0.33-0.80) than the population. Some of this reduction was related to lower marriage rates in schizophrenic patients. The unaffected siblings of schizophrenic patients showed no evidence of any compensatory increase in fitness, but there was a trend towards enhanced fertility among the offspring of schizophrenia patients. Patients with affective psychosis and their relatives did not differ from the general population on any fertility measure.

CONCLUSIONS

Schizophrenia, but not affective psychosis, is associated with reduced biological fertility; this disadvantage is partly explained by marital status and persists into the second generation.

Fertility and pregnancy in women with psychotic disorders

The majority of women with psychotic disorders have children but their pregnancies are at an increased risk of obstetric and psychiatric complications. This paper reviews research into the fertility of women with psychosis and complications occurring during their pregnancies and in the postpartum period. Mesh terms were used to search electronic databases (Medline, Embase, Psychlit and the Cochrane database of systematic reviews). Recent studies have confirmed earlier findings of a low fertility in women with schizophrenia, though fertility is less affected by mood disorders. Psychotic relapse during pregnancy is rare but women with a history of mood disorders (affective psychoses) are at high risk of postpartum relapse. There is a high risk of obstetric complications, mixed evidence of stillbirths and neonatal deaths and there is some weaker evidence of an association with sudden infant death syndrome. A significant proportion of mothers with psychotic disorders have parenting difficulties and lose custody of their infant. Close liaison between all health professionals during pregnancy and postpartum is essential for optimal management of these high risk pregnancies.

Clinical characteristics of schizophrenia in multiply affected Spanish origin families from Costa Rica

Sixty-six families from Costa Rica with multiply ill sets of siblings were examined in detailed clinical evaluations and compared with 59 similarly evaluated families from the USA. Eighty-six unrelated Costa Rican individuals with a schizophrenia spectrum diagnosis and no other ill siblings were an additional comparison group. This study was undertaken to examine whether schizophrenia in Costa Rica has similar clinical and demographic characteristics to that in the USA, whether a homogeneous population such as that in Costa Rica might harbor a specific definable subtype, and whether singletons have similar or differing characteristics from individuals in multiplex families. Overall, schizophrenia in Costa Rica is similar to that in any other geographic location. The same symptoms, sex ratio and age of onset characteristics predominate. However, there was significantly less prevalence of affective symptoms (depression and mania) and drug abuse among the Costa Rican multiplex families by comparison with those from the USA. The families with only one ill member from Costa Rica had significantly more alcohol abuse than the multiply affected families. Within multiplex families (both USA and Costa Rica), age of onset was found to have a familial component. Family sibship size was significantly greater in Costa Rica than the USA for the generation with illness studied. However, these siblings had overall fewer children. In Costa Rica, the male but not the female siblings with schizophrenia had reduced fecundity compared with their well siblings. These families from Costa Rica will be used in further molecular genetic studies to determine whether the illness etiology can be traced to one or more specific genetic linkages.

Mice with reduced NMDA receptor expression display behaviors related to schizophrenia

N-methyl-D-aspartate receptors (NMDARs) represent a subclass of glutamate receptors that play a critical role in neuronal development and physiology. We report here the generation of mice expressing only 5% of normal levels of the essential NMDAR1 (NR1) subunit. Unlike NR1 null mice, these mice survive to adulthood and display behavioral abnormalities, including increased motor activity and stereotypy and deficits in social and sexual interactions. These behavioral alterations are similar to those observed in pharmacologically induced animal models of schizophrenia and can be ameliorated by treatment with haloperidol or clozapine, antipsychotic drugs that antagonize dopaminergic and serotonergic receptors. These findings support a model in which reduced NMDA receptor activity results in schizophrenic-like behavior and reveals how pharmacological manipulation of monoaminergic pathways can affect this phenotype.

Reduced fertility in schizophrenia: here to stay?

Studies of reproduction among individuals with schizophrenia published in this century are reviewed. Past studies suggesting normalization of reproductive deficits are disputed in view of recent reports of a persistent impairment. The handicap appears to be more significant among men with schizophrenia. The implications of these findings for genetic research in schizophrenia are discussed.

Adverse pregnancy outcome in schizophrenic women: occurrence and risk factors

Low birth weight and preterm birth are important predictors of infant mortality and morbidity, and may increase the risk of schizophrenia. These adverse outcomes of pregnancy could be associated, therefore, with increased risk in children genetically predisposed to schizophrenia. The aim of this review was to describe the occurrence of risk factors for low birth weight, preterm birth, and perinatal death among schizophrenic women, and to describe the incidence of those adverse pregnancy outcomes among schizophrenic women. Smoking, substance abuse, and low socioeconomic status are associated with fetal growth retardation, preterm birth, and perinatal death, and also with schizophrenia. Therefore, increased incidence of adverse pregnancy outcome should be expected in schizophrenic women. The available evidence suggests that schizophrenic women are at increased risk of delivering infants with low birth weight, but the existing studies are of small statistical power. Preterm birth and perinatal death have only been investigated little among schizophrenic women. An important focus of future research should be to establish the risk of adverse pregnancy outcome, and to study the association between the suspected risk factors and pregnancy outcome in schizophrenic women. In clinical work with pregnant schizophrenic women, efforts should be made to prevent exposure to suspected risk factors like smoking, substance use, and socioeconomic problems. This could possibly decrease the mortality and morbidity, including the risk of schizophrenia in the offspring, and clarify the importance of environmental and genetic factors in the etiology of schizophrenia.