Psychosis and physical health

Four papers in the Journal this month present findings that help to illuminate the physical health status of individuals with psychotic illnesses. Although individuals with psychosis have been shown to have increased rates of a wide range of physical health conditions, the expected increase in risk of cancers, including those associated with known lifestyle factors, has not been consistently found. Zhuo et al (pp. 704–711) conducted a meta-analysis of results from 12 studies estimating the incidence of lung cancer among those with schizophrenia and failed to find convincing evidence to support a clear association between the two conditions. The authors did, however, find substantial heterogeneity between studies, to the extent that some reported a statistically significant positive association and others a significant negative association. The authors recommend future research endeavours aim to better understand the role of potential underlying mechanisms and the confounding factors that might give rise to the differing findings.

Rates of induced abortion are regarded as an indicator of access to, and quality of, reproductive healthcare. In a Canadian study by Brown et al (pp. 736–743) using both repeated cross-sectional and longitudinal methodologies, women with schizophrenia were found to have higher induced abortion rates compared with women without schizophrenia. The authors recommended women with schizophrenia in high-risk groups, such as younger women, those who have previously given birth and those with other psychiatric comorbidity, be targeted to improve reproductive healthcare outcomes. The authors also comment on the need for qualitative research methods to improve our understanding of the experiences women with schizophrenia have in accessing quality reproductive healthcare, including in relation to accessing effective contraception.

In a prospective study of first-episode psychosis in a UK sample, cardiometabolic risk indicators were found to worsen over the first year following presentation, particularly rates of obesity and glucose dysregulation (Gaughran et al, pp. 712–719). However, no association was found between lifestyle factors at baseline, or type of antipsychotic, and either baseline or 12-month cardiometabolic risk indicators. Those of Black and minority ethnic background were noted to have a greater degree of emerging glucose dysregulation over the first year following presentation. In addition to the effects of lifestyle factors and the side-effects arising from antipsychotic medication, the quality of physical healthcare received by individuals with psychosis has also been identified as an important contributor to the poor physical health outcomes reported.

Using data from the National Audit of Psychosis in England and Wales, Crawford et al (pp. 720–725) examined the quality of physical healthcare received by people with psychosis before and after the introduction of a secondary-care financial incentive intended to improve care (i.e. improve screening and the appropriate offering of interventions). The proportion of patients with psychosis who received high-quality physical healthcare in England rose following the introduction of the financial incentive, and the improvement was greater than that identified for those in Welsh health boards where the incentive was not introduced.

Exposure to adverse environments and later development of schizophrenia

On the basis of the known relationship between exposure to various sources of maternal stress in utero and subsequent risk of schizophrenia, Guo et al (pp. 730–735) tested the long-term effects of prenatal exposure to earthquake in a large Chinese sample. The exposed group had a significantly higher risk of adult schizophrenia, particularly among those exposed during the first trimester of pregnancy.

Testing the relationship between urbanicity and risk of psychosis in a middle-income setting (Brazil), Del-Ben et al (pp. 726–729) found an inverse relationship between population density and incidence of first-episode psychosis. The authors comment on the likelihood that the association reflects the effect of socioeconomic deprivation. Consistent with the results of studies in wealthy countries, the incidence of psychosis was higher in men and among those of Black and minority ethnic background.

The dietary supplement sarcosine – a treatment role in schizophrenia?

In an editorial by Curtis (pp. 697–698), the evidence emerging from a variety of sources to support the role of the glutamatergic N-methyl-d-aspartate receptor in schizophrenia is noted and the possibility of sarcosine as a potential treatment agent is discussed. As a dietary supplement, sarcosine is widely available, and a small number of studies support its potential efficacy in schizophrenia. Curtis calls for larger trials but concludes that even the current state of evidence would support psychiatrists recommending it as an adjunct to conventional antipsychotic treatment.