Majella Byrne

Magnetic resonance imaging of brain in people at high risk of developing schizophrenia

BACKGROUND Schizophrenia is a multifactorial disorder that is associated with disturbed cerebral development. Structural brain-imaging studies have consistently shown that the volumes of some parts of the brain, particularly the mesial temporal lobes, are smaller in patients with schizophrenia than in healthy people. Whether these abnormalities of brain structure predate the onset of symptoms is not known. METHODS 100 people at high risk of developing schizophrenia (two or more first-degree or second-degree relatives affected), 20 patients in their first episode of schizophrenia, and 30 healthy controls underwent magnetic resonance imaging of the brain. The volumes of regions of interest were measured by standard techniques. FINDINGS Mean whole-brain volume was 1356 cm3 (SD 178) in the first-episode group, 1347 cm3 (122) in the high-risk group, and 1334 cm3 (149) in the controls (p=0.8). The mean volume of the left amygdala-hippocampal complex (AHC) was lower in the first-episode group (4.3 cm3 [0.6]) than in the high-risk group (4.6 cm3 [0.6]), and in turn than in the controls (4.8 cm3 [0.7]); these differences were significant (p<0.05) both for absolute volumes and values adjusted for brain volume and other confounders. The right AHC showed a similar pattern (absolute volumes 4.5 cm3 [0.7], 4.8 cm3 [0.6], 4.9 cm3 [0.9], respectively). Both thalamic nuclei were significantly smaller in the high-risk group than in the control group. INTERPRETATION People at high risk of developing schizophrenia for genetic reasons have several structural brain abnormalities that are similar to those in patients with the disorder. If at-risk individuals with particularly small AHC or thalami are most likely to develop schizophrenia, this feature might assist in early detection and treatment.

The anthropometric assessment of dysmorphic features in schizophrenia as an index of its developmental origins.

BACKGROUND Evidence suggests that schizophrenia may be a disorder with origins in early intrauterine mal-development. We have constructed a comprehensive anthropometric scale for the evaluation of dysmorphic features as an index of the nature and timing of developmental disturbance. METHOD A detailed set of craniofacial and bodily measures was compiled and applied to 174 patients with schizophrenia and 80 matched control subjects. RESULTS Patients had significantly higher scores on this scale and displayed multiple anomalies of the craniofacial region with an overall narrowing and elongation of the mid-face and lower face. Twelve craniofacial anomalies independently distinguished patients from controls and these variables correctly classified 95% of patients and 80% of control subjects. CONCLUSIONS This new scale, while procedurally more exacting than the Waldrop scale, more clearly defines the topography of anomalies previously suspected in individuals with schizophrenia. These findings constitute direct evidence for disturbed craniofacial development in schizophrenia and indicate origins in the foetal period during which the characteristic human facial pattern evolves in close association with brain differentiation.

Neuropsychological change in young people at high risk for schizophrenia: results from the first two neuropsychological assessments of the Edinburgh High Risk Study.

BACKGROUND Studies of groups of individuals who have a genetically high risk of developing schizophrenia, have found neuropsychological impairments that highlight likely trait markers of the schizophrenic genotype. This paper describes the change in neuropsychological function and associations with psychiatric state of high risk participants during the first two assessments of the Edinburgh High Risk Study. METHODS Seventy-eight high risk participants and 22 normal controls, age and sex matched completed two neuropsychological assessments 18 months to 2 years apart. The areas of function assessed include intellectual function, executive function, learning and memory, and verbal ability and language. RESULTS The high risk participants performed significantly worse on particular tests of verbal memory and executive function over the two assessments than matched controls. Those high risk participants who experienced psychotic symptoms were found to exhibit a decline in IQ and perform worse on tests of verbal memory and executive function than those without symptoms. An increase in psychotic symptoms between the two assessments in the high risk group was found to be associated with an apparent decline in IQ and memory. CONCLUSIONS The results suggest that the development of psychotic symptoms is preceded by a decline in IQ and memory. This may reflect a general and a more specific disease process respectively.

Obstetric conditions and risk of first admission with schizophrenia: A Danish national register based study

A range of complications of pregnancy, abnormal fetal growth and development, and complications of delivery have been associated with increased risk of schizophrenia. Few studies have been able to adjust for a broad range of potential confounding factors. A national population nested case-control study based on Danish longitudinal registers was conducted to investigate the risk of schizophrenia associated with exposure to a range of obstetric events. The sample included 1039 first admissions to, or contacts with Danish psychiatric services with an ICD-8 or ICD-10 diagnosis of schizophrenia and 24, 826 individually matched controls. Adjusting for the other obstetric factors, family psychiatric history, and socio-economic and demographic factors, risk of schizophrenia was associated with maternal non-attendance at antenatal appointments (Incidence Rate Ratio (IRR) 2.08, 95% CI: 1.0, 4.4), gestational age of 37 weeks or below (IRR 1.51, 95% CI: 1.0, 2.2), maternal influenza (IRR 8.2, 95% CI: 1.4, 48.8), preeclampsia (IRR 2.72, 95% CI: 1.0, 7.3), threatened premature delivery (IRR 2.39, 95% CI: 1.4, 4.1), haemorrhage during delivery (IRR 2.43, 95% CI: 1.1, 5.6), manual extraction of the baby (IRR 2.15, 95% CI: 1.1, 4.4), and maternal sepsis of childbirth and the puerperium (IRR 2.91, 95% CI: 1.1, 7.9). There was no significant interaction between the obstetric factors and either sex or family psychiatric history. The data suggest a modest association between prematurity, indicators of hypoxia, maternal infections, and maternal behaviours and risk of the later development of schizophrenia after adjusting for a number of possible confounding factors.

Edinburgh high risk study — findings after four years: demographic, attainment and psychopathological issues

This study reports findings of the Edinburgh High Risk Study four years after it began. This study is designed to explore the pathogenesis of schizophrenia by examining a large sample of young adults aged 16-25 years who are at enhanced risk of developing schizophrenia by having two close relatives with the disorder, and comparing them with matched controls. This paper presents comparisons of the high risk subjects, well controls and subjects with first-episode schizophrenia in terms of demographic, childhood, psychopathological, educational and employment, forensic and social work variables. High risk subjects have more psychological difficulties, poorer educational and employment attainment, and more social work contact than controls. The enhanced social work involvement related to the presence of a schizophrenic parent (especially a mother) but the other difficulties could not be attributed to that situation. Neurotic, partially held psychotic and fully held psychotic symptoms all occurred in both subjects and controls, but all were significantly more common in high risk subjects. Clinical schizophrenia has so far developed in 10 high risk subjects and in no controls. Possible confounding effects of drug or alcohol misuse were considered but were found unlikely to be important.

Neuropsychological assessment of young people at high genetic risk for developing schizophrenia compared with controls : preliminary findings of the Edinburgh High Risk Study (EHRS)

BACKGROUND Finding risk indicators for schizophrenia among groups of individuals at high genetic risk for the disorder, has been the driving force of the high risk paradigm. The current study describes the preliminary results of a neuropsychological assessment battery conducted on the first 50% of subjects from the Edinburgh High Risk Study. METHODS One hundred and four high risk subjects and 33 normal controls, age and sex matched, were given a neuropsychological assessment battery. The areas of function assessed and reported here include intellectual function, executive function, perceptual motor speed, mental control/ encoding, verbal ability and language, learning and memory measures, and handedness. RESULTS The high risk subjects performed significantly more poorly than the control subjects in the following domains of neuropsychological function: intellectual function, executive function, mental control/encoding and learning, and memory. Controlling for IQ, high risk subjects made significantly more errors on the Hayling Sentence Completion Test (HSCT), took longer to complete section A of the HSCT, had lower scores on the delayed recall condition of the visual reproductions subtest of the Wechsler Memory Scale-Revised, and had significantly poorer Rivermead Behavioural Memory Test (RBMT) standardized scores. The presence of significant group by IQ interactions for the RBMT and time to complete section A of the HSCT suggested that differences among the groups were more marked in the lower IQ range. Performance on the HSCT was found to be related to the degree of family history of schizophrenia. CONCLUSIONS High risk subjects performed more poorly than controls on all tests of intellectual function and on aspects of executive function and memory.

Disorganization/Cognitive and Negative Symptom Dimensions in the At-Risk Mental State Predict Subsequent Transition to Psychosis

OBJECTIVE The at-risk mental state (ARMS) is associated with a very high risk of psychosis, but it is difficult to predict which individuals will later develop psychosis on the basis of their presenting symptoms. We investigated psychopathological dimensions in subjects with an ARMS and examined whether particular symptom dimensions predicted subsequent transition to psychosis. METHOD The sample comprised 122 subjects (aged 16-35 years) meeting Personal Assessment and Crisis Evaluation clinic criteria for the ARMS recruited through Outreach and Support in South London, a clinical service for people with an ARMS. A principal axis factor analysis was performed on symptom scores, obtained at presentation from the Comprehensive Assessment of the At-Risk Mental State, using Varimax rotation. The relationship between dimension scores and transition to psychosis during the following 24 months was then examined employing Cox regression analysis. RESULTS Factor analysis gave rise to a 5-factor solution of negative, anxiety, disorganization/cognitive, self-harm, and manic symptom dimensions, accounting for 37% of the total variance. Scores on the negative and on the disorganization/cognitive dimensions were associated with transition to psychosis during the follow-up period (P = 0.044 and P = 0.005, respectively). CONCLUSION The symptoms of the ARMS have a dimensional structure similar to that evident in patients with schizophrenia except for the positive symptom dimension. The association between scores on the disorganization/cognitive and negative dimensions and later transition is consistent with independent evidence that formal thought disorder, subjective cognitive impairments, and negative symptoms are linked to the subsequent onset of psychosis.

Parental socio-economic status and risk of first admission with schizophrenia - A Danish national register based study

We examined the relationships between measures of parental and personal socio-economic status and risk of first admission with schizophrenia in order to identify whether low socio-economic status in cases is a consequence of the illness process or is a familial risk factor. A national population-based nested case-control study based on Danish longitudinal registers was conducted. The sample included 7704 first admissions with ICD-8 or ICD-10 schizophrenia admitted to a psychiatric facility in Denmark between 1981 and 1998 and 192 590 individually time-, age- and gender-matched population controls identified through national registers, and their parents and siblings. Socio-economic indicators measured in the year prior to admission and background factors for cases, controls, and parents were included. Risk of schizophrenia was associated with unemployment, low educational attainment, being single, lower wealth status, low income, and being childless. Increased risk was associated with a family history of psychiatric disorders, birth in urban areas, birth outside of Denmark, and having three of more siblings. Increased risk of schizophrenia was associated with parental unemployment and parental lower income, but was not associated with parental wealth. Risk for schizophrenia was associated with higher education in parents. Increased risk of first admission was associated with socio-economic disadvantage in cases. Although we found some associations between parental unemployment and parental higher education and risk of schizophrenia, there was little evidence that low parental socio-economic status increases the risk of schizophrenia.

Neuropsychology, Genetic Liability, and Psychotic Symptoms in Those at High Risk of Schizophrenia

Neuropsychological assessments were compared among individuals at enhanced genetic risk of schizophrenia (n = 157) and controls (n = 34). The relationship between cognitive impairments and the presence of psychotic symptoms and measures of genetic risk was explored in the high-risk subjects. Neuropsychological differences were identified in many areas of function and were not accounted for by the presence of psychotic symptoms. Genetic liability was not associated with neuropsychological performance or with psychotic symptoms, but exploratory analysis showed some tests were associated with both liability measures. These results suggest that what is inherited is not the disorder itself but a state of vulnerability manifested by neuropsychological impairment, occurring in many more individuals than are predicted to develop the disorder.

Perceptions of disadvantage, ethnicity and psychosis

BACKGROUND People from Black ethnic groups (African-Caribbean and Black African) are more prone to develop psychosis in Western countries. This excess might be explained by perceptions of disadvantage. AIMS To investigate whether the higher incidence of psychosis in Black people is mediated by perceptions of disadvantage. METHOD A population-based incidence and case-control study of first-episode psychosis (Aetiology and Ethnicity in Schizophrenia and Other Psychoses (AESOP)). A total of 482 participants answered questions about perceived disadvantage. RESULTS Black ethnic groups had a higher incidence of psychosis (OR= 4.7, 95% CI 3.1-7.2). After controlling for religious affiliation, social class and unemployment, the association of ethnicity with psychosis was attenuated (OR=3.0, 95% CI 1.6-5.4) by perceptions of disadvantage. Participants in the Black non-psychosis group often attributed their disadvantage to racism, whereas Black people in the psychosis group attributed it to their own situation. CONCLUSIONS Perceived disadvantage is partly associated with the excess of psychosis among Black people living in the UK. This may have implications for primary prevention.