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

Werf, M. van der; Hanssen, M.S.S.; Köhler, Sebastian; Verkaaik, Mike; Verhey, Frans R.J.; Winkel, Ruud van; Os, Jim van; Allardyce, Judith

doi:10.1017/s0033291712002796

Cited by 131 publications

(91 citation statements)

References 37 publications

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“…This finding is in agreement with previous studies that reported a higher prevalence of schizophrenia among males than among females 22–24…”

Section: Discussionsupporting

confidence: 94%

Clinical and biochemical study of D-serine metabolism among schizophrenia patients

El-Tallawy¹,

Saleem²,

El-Ebidi³

et al. 2017

NDT

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BackgroundSchizophrenia is a typical N-methyl-d-aspartate receptor (NMDA-R) hypofunction disorder. Decreased d-serine (d-Ser) levels in the periphery occur in schizophrenia and may reflect decreased availability of d-Ser to activate NMDA-R in the brain.ObjectiveThe objective of this study was to investigate the role of d-Ser metabolism in the pathogenesis of schizophrenia via biochemical assays and correlates, the serum level of d-Ser, d-serine racemase (SR) (responsible for its formation from l-serine [l-Ser]) and d-amino acid oxidase (DAAO) (responsible for its catabolism), among different clinical types of schizophrenia patients.Patients and methodsThis cross-sectional case–control study was carried out on 100 patients and 50 controls. They were recruited from the outpatients’ psychiatric unit of the Neuropsychiatric Department of Assiut University Hospital, Upper Egypt. The type of schizophrenia was determined according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), while the severity of schizophrenia was determined according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Serum d-Ser levels were estimated using high-performance liquid chromatography (HPLC), while serum SR and DAAO were measured using commercially available enzyme-linked immunosorbent assay kits.ResultsThere were significantly lower mean serum levels of d-Ser and SR and significantly higher mean serum levels of DAAO (P-value <0.01 for each) among schizophrenia patients when compared with the control group. Paranoid schizophrenia had the highest frequency, with a significantly lower serum levels of d-Ser and SR in the residual type and significantly higher serum levels of DAAO in undifferentiated and catatonic types. Combined receiver-operating characteristic curve for serum d-Ser, SR and DAAO indicated that the best serum level cutoff points at which schizophrenia manifestations started to appear were ≤ 61.4 mg/L for d-Ser, ≤ 15.5 pg/mL for SR and >35.6 pg/mL for DAAO.ConclusionThe present study confirms that disturbed d-Ser metabolism could be implicated in the pathogenesis of schizophrenia.

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“…This finding is in agreement with previous studies that reported a higher prevalence of schizophrenia among males than among females 22–24…”

Section: Discussionsupporting

confidence: 94%

Clinical and biochemical study of D-serine metabolism among schizophrenia patients

El-Tallawy¹,

Saleem²,

El-Ebidi³

et al. 2017

NDT

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“…Although schizophrenia has a weak male bias on average (7 males: 5 females), this ratio is increased in younger males (<20 years old) where two males to every female are affected [186,187,188,189]. Males also have an earlier age of onset of schizophrenia, between 18–25 years of age, compared with the female age of onset which is 25–35 years [73].…”

Section: Male-biased Disordersmentioning

confidence: 99%

Sex: A Significant Risk Factor for Neurodevelopmental and Neurodegenerative Disorders

et al. 2018

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Males and females sometimes significantly differ in their propensity to develop neurological disorders. Females suffer more from mood disorders such as depression and anxiety, whereas males are more susceptible to deficits in the dopamine system including Parkinson’s disease (PD), attention-deficit hyperactivity disorder (ADHD) and autism. Despite this, biological sex is rarely considered when making treatment decisions in neurological disorders. A better understanding of the molecular mechanism(s) underlying sex differences in the healthy and diseased brain will help to devise diagnostic and therapeutic strategies optimal for each sex. Thus, the aim of this review is to discuss the available evidence on sex differences in neuropsychiatric and neurodegenerative disorders regarding prevalence, progression, symptoms and response to therapy. We also discuss the sex-related factors such as gonadal sex hormones and sex chromosome genes and how these might help to explain some of the clinically observed sex differences in these disorders. In particular, we highlight the emerging role of the Y-chromosome gene, SRY, in the male brain and its potential role as a male-specific risk factor for disorders such as PD, autism, and ADHD in many individuals.

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“…Although schizophrenia has a weak male bias on average (7 males:5 females), this ratio is increased in younger males (<20 years old) where two males to every female are affected (Castle et al, 1993;McGrath et al, 2004McGrath et al, , 2008van der Werf et al, 2014). Considering that dopaminergic dysfunction in the prefrontal cortex is involved in the pathophysiology of schizophrenia, DA machinery genes such as COMT have been implicated in a convergent functional genomics approach (integration of GWAS data with other gene expression studies), copy number variant analysis and systematic meta-analysis (Allen et al, 2008;Ayalew et al, 2012;Saus et al, 2010).…”

Section: Schizophreniamentioning

confidence: 99%

Biological factors underlying sex differences in neurological disorders

Loke

Harley

Lee

2015

The International Journal of Biochemistry & Cell Biology

129

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

Abstract: 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.

Cited by 131 publications

References 37 publications

Clinical and biochemical study of D-serine metabolism among schizophrenia patients

Clinical and biochemical study of D-serine metabolism among schizophrenia patients

Sex: A Significant Risk Factor for Neurodevelopmental and Neurodegenerative Disorders

Biological factors underlying sex differences in neurological disorders

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