Odds Of Schizophrenia Research Articles

Mental disorders among young adults of immigrant background: a nationwide register study in Norway

PurposePrevious research indicates increased risk of various mental disorders in immigrant populations, particularly for schizophrenia and PTSD. However, findings are inconclusive due to variations in contextual factors, characteristics of immigrant groups and study design. Our study aims to investigate prevalence differences of receiving an ICD-10 psychiatric diagnosis between 2008 and 2016 among four first-generation immigrant groups and one second-generation immigrant group compared to ethnic Norwegians.MethodsLinked register data from the Norwegian Patient Registry and Statistics Norway were utilised. The sample (age 18–35) comprises 758,774 ethnic Norwegians, 61,124 immigrants originating from Poland, Somalia, Iran and Pakistan and 4630 s-generation Pakistani immigrants. Age- and gender-adjusted binary logistic regression models were applied.ResultsThe odds of schizophrenia were significantly elevated for all groups except for Poles. The highest odds were observed for second-generation Pakistani immigrants (adjusted OR 2.72, 95% CI 2.21–3.35). For PTSD, the odds were significantly increased for Somalis (aOR 1.31, 95% CI 1.11–1.54), second-generation Pakistani immigrants (aOR 1.37, 95% CI 1.11–1.70), and in particular for Iranians (aOR 3.99, 95% CI 3.51–4.54). While Iranians showed similar or higher odds of receiving the vast majority of psychiatric diagnoses, the remaining groups showed lower or similar odds compared to ethnic Norwegians.ConclusionOur findings suggest considerable prevalence differences in receiving a psychiatric diagnosis according to country of origin and generational status compared to ethnic Norwegian controls. The general pattern was lower prevalence of most ICD-10 mental disorders for the majority of immigrant groups compared to ethnic Norwegians, except for schizophrenia and PTSD.

The relationship between childhood trauma and schizophrenia in the Genomics of Schizophrenia in the Xhosa people (SAX) study in South Africa.

Evidence from high-income countries suggests that childhood trauma is associated with schizophrenia. Studies of childhood trauma and schizophrenia in low and middle income (LMIC) countries are limited. This study examined the prevalence of childhood traumatic experiences among cases and controls and the relationship between specific and cumulative childhood traumatic experiences and schizophrenia in a sample in South Africa. Data were from the Genomics of Schizophrenia in the South African Xhosa people study. Cases with schizophrenia and matched controls were recruited from provincial hospitals and clinics in the Western and Eastern Cape regions in South Africa. Childhood traumatic experiences were measured using the Childhood Trauma Questionnaire (CTQ). Adjusted logistic regression models estimated associations between individual and cumulative childhood traumatic experiences and schizophrenia. Traumatic experiences were more prevalent among cases than controls. The odds of schizophrenia were 2.44 times higher among those who experienced any trauma than those who reported no traumatic experiences (95% CI 1.77-3.37). The odds of schizophrenia were elevated among those who experienced physical/emotional abuse (OR 1.59, CI 1.28-1.97), neglect (OR 1.39, CI 1.16-1.68), and sexual abuse (OR 1.22, CI 1.03-1.45) compared to those who did not. Cumulative physical/emotional abuse and neglect experiences increased the odds of schizophrenia as a dose-response relationship. Childhood trauma is common in this population. Among many other benefits, interventions to prevent childhood trauma may contribute to a decreasing occurrence of schizophrenia.

Long-term effect of prenatal exposure to malnutrition on risk of schizophrenia in adulthood: Evidence from the Chinese famine of 1959–1961

BackgroundSchizophrenia is a common major mental disorder and prenatal nutritional deficiency may increase its risk. We aimed to investigate long-term impact of prenatal exposure to malnutrition on risk of schizophrenia in adulthood using the Chinese famine of 1959–1961 as a natural experiment. MethodsWe obtained data from the Second National Sample Survey on Disability implemented in 31 provinces in 2006, and restricted our analysis to 387,093 individuals born from 1956 to 1965. Schizophrenia was ascertained by psychiatrists based on the International Statistical Classification of Diseases, Tenth Revision. Famine severity was defined as cohort size shrinkage index. The famine effect on adult schizophrenia was estimated by difference-in-difference models, established by examining the variations of famine exposure across birth cohorts. ResultsCompared with the reference cohort of 1965, famine cohorts (1959–1962) had significantly higher odds (OR: 1.84; 95% CI: 1.13, 3.00; P = 0.014) of schizophrenia in the rural population. After adjusting for multiple covariates, this association remained significant (OR: 1.82; 95% CI: 1.11, 2.98; P = 0.018). We did not observe statistically significant differences in odds of schizophrenia among famine cohorts compared with the reference cohort in the urban population. ConclusionsPrenatal malnutrition exposure has a detrimental impact on risk of schizophrenia in adulthood in the rural population. Further studies were needed to investigate corresponding mechanisms on this topic.

Snus use and risk of schizophrenia and non-affective psychosis

BackgroundRecent studies suggest a possible causal role for smoking in schizophrenia and psychosis. Most studies have focused on cigarette smoking, the most common form of tobacco use, but other forms of tobacco exist, including smokeless products such as Swedish snuff (or “snus”). MethodsWe explored whether snus use is associated with schizophrenia and non-affective psychotic illness in a large Swedish registry data set. The majority of participants were aged 18 or 19 at the time of assessment. ResultsWe observed a positive association between snus use and odds of schizophrenia in all analyses, but the magnitude of the association was small and the confidence interval wide, consistent with no association (fully adjusted HR 1.03, 95% 0.70–1.54). A similar pattern was observed for non-affective psychosis, but the magnitude of the association was somewhat greater and the confidence intervals narrower, so that these analyses provided stronger statistical evidence for this association (fully adjusted HR 1.22, 95% CI, 1.00–1.48). ConclusionsOur results therefore provide modest evidence for an association between snus use and risk for non-affective psychosis. This is consistent with emerging evidence from a range of studies and methodologies that tobacco use may be a risk factor for psychotic illness. However, our results provide some evidence against the hypothesis that it is the burnt products of cigarette smoke that are psychotogenic.

Paternal age and schizophrenia: further support for an association.

Advanced paternal age has been proposed as a risk factor for later development of schizophrenia in offspring, although studies are not conclusive. De novo mutations arising in paternal germ cells have been suggested as the underlying mechanism. The hypothesized association was investigated in a population-based case-control study comprising 524 subjects with schizophrenia and 1,043 matched comparison subjects selected from registers. Birth records with data on parental age were retrieved manually. Odds ratios were computed, with controls for maternal age, parity, marital status, socioeconomic status, maternal psychotic illness, and obstetric complications. The odds of schizophrenia in offspring of fathers 45 years old or older were 2.8 times as great as in offspring of fathers aged 20-24 years. These findings confirm previous reports of a higher risk for schizophrenia associated with advanced paternal age. They may be of interest for further studies on the genetic mechanisms behind schizophrenia.