Psychotic disorder and educational achievement: a family-based analysis.

BACKGROUND: Early social and cognitive alterations in psychotic disorder, associated with familial liability and environmental exposures, may contribute to lower than expected educational achievement. The aims of the present study were to investigate (1) how differences in educational level between parents and their children vary across patients, their healthy siblings, and healthy controls (effect familial liability), and across two environmental risk factors for psychotic disorder: childhood trauma and childhood urban exposure (effect environment) and (2) to what degree the association between familial liability and educational differential was moderated by the environmental exposures. METHODS: Patients with a diagnosis of non-affective psychotic disorder (n = 629), 552 non-psychotic siblings and 326 healthy controls from the Netherlands and Belgium were studied. Participants reported their highest level of education and that of their parents. Childhood trauma was assessed with the Dutch version of the Childhood Trauma Questionnaire-Short Form. Urban exposure, expressed as population density, was rated across five levels. RESULTS: Overall, participants had a higher level of education than their parents. This difference was significantly reduced in the patient group, and the healthy siblings displayed intergenerational differences that were in between those of controls and patients. Higher levels of childhood urban exposure were also associated with a smaller intergenerational educational differential. There was no evidence for differential sensitivity to childhood trauma and childhood urbanicity across the three groups. CONCLUSION: Intergenerational difference in educational achievements is decreased in patients with psychotic disorder and to a lesser extent in siblings of patients with psychotic disorder, and across higher levels of childhood urban exposure. More research is required to better understand the dynamics between early social and cognitive alterations in those at risk in relation to progress through the educational system and to understand the interaction between urban environment and educational outcomes.

Childhood trauma and childhood urbanicity in relation to psychotic disorder.

BACKGROUND: Urban upbringing and childhood trauma are both associated with psychotic disorders. However, the association between childhood urbanicity and childhood trauma in psychosis is poorly understood. The urban environment could occasion a background of social adversity against which any effect of childhood trauma increases. Also, any impact of the urban environment on likelihood of exposure to childhood trauma could be stronger in children who later develop psychotic disorder. The aim of this study was twofold: (1) to investigate whether childhood urbanicity moderates the effect of childhood trauma, in a model predicting psychotic disorder; (2) to investigate whether there is an association between the urban environment and childhood trauma and whether this is moderated by genetic liability for psychotic disorder. METHODS: Patients with a diagnosis of non-affective psychotic disorder (n = 1119) and 589 healthy controls from the Netherlands and Belgium were studied. Childhood trauma was assessed with the Dutch version of the Childhood Trauma Questionnaire Short Form. Urban exposure was defined at four levels, considering the population density, using data from Statistics Netherlands and the equivalent database in Belgium. RESULTS: There was a significant interaction between childhood urbanicity on the one hand and childhood trauma on the other, indicating that trauma was significantly associated with psychotic disorder, with increasing odds ratios for higher levels of childhood urbanicity. In addition, there was weak evidence that childhood urbanicity was associated with childhood trauma in the patient group: higher levels of childhood urbanicity were associated with higher trauma scores. CONCLUSION: The urban environment may moderate the risk-increasing effect of childhood trauma for psychotic disorder and childhood urbanicity may be a risk factor for childhood trauma in individuals who later develop psychotic disorder.

Evidence that childhood urban environment is associated with blunted stress reactivity across groups of patients with psychosis, relatives of patients and controls.

PURPOSE: Psychosis is associated with urban upbringing, and increased emotional reactivity is associated with psychosis. The aim of this study was to examine to what degree urban upbringing impacts emotional reactivity, and how this may be relevant for psychotic disorder and familial risk of psychotic disorder. METHODS: Patients with a diagnosis of non-affective psychotic disorder (n = 57), 59 first degree relatives of patients and 75 healthy comparison subjects were studied with the experience sampling method (a random time sampling technique to assess affective experience in relation to fluctuating stressors in the flow of daily life), to measure a change in negative affect in relation to subjective stress. Urban exposure was defined at 5 levels, considering the population density and the number of moves between birth and the 15th birthday, using data from the Dutch Central Bureau of Statistics and the equivalent database in Belgium. RESULTS: Multilevel random regression analyses showed that urban upbringing was consistently and strongly associated with a reduced increase in negative affect in relation to SS in adulthood in a dose-response fashion in all three groups. Regression coefficients in the patient group decreased from 0.148 (p < 0.001) in the lowest urbanicity level to 0.094 (p < 0.001) in the highest urbanicity level. CONCLUSION: The findings suggest that urban upbringing may occasion "habituation" rather than "sensitization" across groups, which may or may not be relevant for the onset of psychotic disorder.

Evidence that reduced gray matter volume in psychotic disorder is associated with exposure to environmental risk factors.

The aim of this study was to examine whether cannabis use, childhood trauma and urban upbringing are associated with total gray matter volume (GMV) in individuals with (risk for) psychotic disorder and whether this is sex-specific. T1-weighted MRI scans were acquired from 89 patients with a psychotic disorder, 95 healthy siblings of patients with psychotic disorder and 87 controls. Multilevel random regression analyses were used to examine main effects and interactions between group, sex and environmental factors in models of GMV. The three-way interaction between group, sex and cannabis (χ2 =12.43, p<0.01), as well as developmental urbanicity (χ2 = 6.29, p = 0.01) were significant, indicating that cannabis use and developmental urbanicity were associated with lower GMV in the male patient group (cannabis: B= -32.54, p < 0.01; developmental urbanicity: B= -10.23, p=0.03). For childhood trauma, the two-way interaction with group was significant (χ2 = 5.74, p = 0.02), indicating that childhood trauma was associated with reduced GMV in the patient group (B=-9.79, p=0.01). The findings suggest that reduction of GMV in psychotic disorder may be the outcome of differential sensitivity to environmental risks, particularly in male patients.

No Evidence of Association between Childhood Urban Environment and Cortical Thinning in Psychotic Disorder.

BACKGROUND: The alterations in cortical morphology, such as cortical thinning, observed in psychotic disorder, may be the outcome of interacting genetic and environmental effects. It has been suggested that urban upbringing may represent a proxy environmental effect impacting cortical thickness (CT). Therefore, the current study examined whether the association between group as a proxy genetic variable (patients with psychotic disorder [high genetic risk], healthy siblings of patients [intermediate risk] and healthy control subjects [average risk]) and CT was conditional on different levels of the childhood urban environment and whether this was sex-dependent. METHODS: T1-weighted MRI scans were acquired from 89 patients with a psychotic disorder, 95 non-psychotic siblings of patients with psychotic disorder and 87 healthy control subjects. Freesurfer software was used to measure CT. Developmental urban exposure was classified as low, medium, and high, reflecting the population density and the number of moves between birth and the 15th birthday, using data from the Dutch Central Bureau of Statistics and the equivalent database in Belgium. Multilevel regression analyses were used to examine the association between group, sex, and urban upbringing (as well as their interactions) and cortical CT as the dependent variable. RESULTS: CT was significantly smaller in the patient group compared to the controls (B = -0.043, p <0.001), but not in the siblings compared to the controls (B = -0.013, p = 0.31). There was no main effect of developmental urbanicity on CT (B = 0.001, p = 0.91). Neither the three-way group × urbanicity × sex interaction (χ2 = 3.73, p = 0.16), nor the two-way group × urbanicity interaction was significant (χ2 = 0.51, p = 0.77). CONCLUSION: The negative association between (familial risk for) psychotic disorder and CT was not moderated by developmental urbanicity, suggesting that reduced CT is not the outcome of familial sensitivity to the proxy environmental factor 'urban upbringing'.

Schizophrenia and 1957 pandemic of influenza: meta-analysis.

Maternal influenza during pregnancy is a controversial risk factor for schizophrenia in the child. We conducted a meta-analysis to examine whether birth during the 9-month period after the pandemic of 1957 was a risk factor for schizophrenia. Studies that compared the risk of schizophrenia among subjects born after the pandemic with that among those born in corresponding time periods in surrounding years were divided into those conducted in the United States, Europe, or Australia (type A studies, n = 8) and those from Japan, where the epidemic came in 2 waves (type B studies, n = 3). Other studies examined the risk among subjects born to mothers who were pregnant during the pandemic and reported having had influenza (type C studies, n = 2). Relative risks (RRs) were extracted or calculated for each month and/or trimester of possible exposure by 2 independent authors. All analyses were performed using a fixed-effects model. The weighted results of the type A studies did not indicate a significantly increased risk of schizophrenia among children exposed during any trimester or month of prenatal life. Not a single study found a significant first- or second-trimester effect. The mean weighted RR for subjects who were in their first, second, or third trimester of prenatal life during the pandemic (8 effect sizes) was 0.91 (95% confidence interval [CI]: 0.85-0.98), 1.00 (95% CI: 0.93-1.07), and 1.05 (95% CI: 0.98-1.12), respectively. The pooled results of the type B and type C studies were also negative. Given high infection rates during the pandemic (about 50%), these results do not support the maternal influenza hypothesis.