Biomedical subjects

Peter McGuffin

Publications and source records attributed to Peter McGuffin.

43 records · Page 3Linked to original sources

PubMed2002

Neuroticism, extraversion, life events and depression. The Cardiff Depression Study.

BACKGROUND: Certain personality traits may mediate the relationship between familiality and adversity in causing depression. AIMS: To examine whether the neuroticism and extraversion scales of the Eysenck Personality Inventory (EPI) represent enduring traits underlying the vulnerability to respond to adversity by developing depressive episodes. METHOD: A total of 108 subjects with depression and their siblings were compared with 105 healthy control subjects and their siblings. All were interviewed using the Schedules for the Clinical Assessment of Neuropsychiatry and the Life Events and Difficulties Schedule. Subjects also completed the EPI. RESULTS: Both neuroticism and extraversion were familial and correlated with mood and life event measures. There were no differences on either measure between the never-depressed siblings of probands with depression and controls. Regression analyses showed that the major influence on neuroticism was current mood. CONCLUSIONS: Neither extraversion nor neuroticism measures trait vulnerability to depression, and neuroticism scores mainly reflect symptoms of depression.

Adult↗

PubMed2002

The genetic basis for psychiatric illness in man.

Following the influential genetic studies of Heston and Kety, there has been growing acceptance of the role of genes in determining behaviour. It is now recognized that most types of behaviour, from normal variations in traits such as personality to complex psychiatric disorders, are influenced not only by environmental factors but also by multiple genes. While twin and adoption studies have been vital in demonstrating the heritability of behaviour, the focus is now on the identification of the genes involved using the molecular genetic strategies linkage analysis and allelic association. This article will discuss techniques that have been used in psychiatric genetics, and how they have advanced our understanding of complex behaviour.

Chromosome Mapping↗

PubMed2002

Clinical variables and genetic loading for schizophrenia: analysis of published Danish adoption study data.

Schizophrenia shows considerable clinical variation, but the relationship between clinical variables and degree of genetic loading for schizophrenia is unclear. We investigated this by analyzing published data from the adoption study of Kety et al. (1994) in Denmark. We sought to determine which clinical variables in proband adoptees with chronic schizophrenia predicted risk of schizophrenia in their biological relatives, using logistic regression analysis. We found that risk of chronic schizophrenia in relatives was predicted by the presence of pervasive negative symptoms (odds ratio [OR] = 9.44, 95% confidence interval [CI] = 1.98-45.01) and absence of pervasive positive symptoms (OR = 0.09, 95% CI = 0.01-0.78) in probands. Pervasive negative symptoms were defined by the presence of all of the symptoms: social withdrawal, autistic behavior, poverty of thought/speech, and flat affect. Pervasive positive symptoms were defined by the presence of all of the symptoms: suspiciousness/ideas of reference, delusions, auditory hallucinations, and other hallucinations. These clinical variables may be useful for refining phenotypic definitions of schizophrenia in molecular genetic studies.

Adoption↗

PubMed2002

A twin study of genetic relationships between psychotic symptoms.

OBJECTIVE: Biometrical model fitting was applied to clinical data from twins to investigate whether operationally defined schizophrenic, schizoaffective, and manic syndromes share genetic risk factors. METHOD: Seventy-seven monozygotic and 89 same-sex dizygotic twin pairs in which the proband met the Research Diagnostic Criteria (RDC) for lifetime-ever schizophrenic, schizoaffective, or manic syndrome were ascertained from the Maudsley Twin Register in London. The syndromes were defined non-hierarchically. Correlations in liability were calculated for each syndrome in the monozygotic and dizygotic pairs and across the three pairings of schizophrenic-manic, schizophrenic-schizoaffective, and schizoaffective-manic syndromes both within probands and within pairs. For the three syndromes considered together, an independent pathway model was fitted. RESULTS: The model fitting showed significant genetic correlations between all three syndromes. There was evidence of both common and syndrome-specific genetic contributions to the variance in liability to the schizophrenic and manic syndromes, but the genetic liability to the schizoaffective syndrome was entirely shared in common with the other two syndromes. In contrast, environmental liability to the schizoaffective syndrome was not shared with the other syndromes. CONCLUSIONS: If diagnostic hierarchies are relaxed, there is a degree of overlap in the genes contributing to RDC schizophrenic, schizoaffective, and manic syndromes. Supplementing the traditional approach of assigning a single main lifetime diagnosis with information on within-person comorbidity of psychotic syndromes may provide valuable information about the familial aggregation of psychotic symptoms.

Adolescent↗

PubMed2002

Heritability of Schneider's first-rank symptoms.

BACKGROUND: Schneider's first-rank symptoms are given particular weight when making a diagnosis of schizophrenia, but the nuclear syndrome, characterised by one or more first-rank symptoms, has been found previously to have no heritability. AIMS: To estimate the heritability of the nuclear syndrome. METHOD: A total of 224 twin pairs (106 monozygotic, 118 same-gender dizygotic) were ascertained from the Maudsley Twin Register in London via probands with any psychosis. Lifetime-ever first-rank symptoms were rated using the OPCRIT checklist. Probandwise concordance rates were calculated for the nuclear syndrome and a heritability estimate was derived from biometric model fitting. RESULTS: Probandwise concordance rates were 13/49 (26.5%) for monozygotic and 0/45 to 2/46 (0.0-4.3%) for dizygotic pairs. The heritability estimate for the best-fitting model was 71% (95% CI 57-82). CONCLUSIONS: These results indicate that the nuclear syndrome shows substantial heritability, although this is slightly lower than that for schizophrenia as defined by the DSM and ICD systems.

Adult↗

PubMed2002

Observer effects and heritability of childhood attention-deficit hyperactivity disorder symptoms.

BACKGROUND: Twin studies have found that childhood attention-deficit hyperactivity disorder (ADHD) has a strong genetic component. Estimates of heritability, the extent of non-additive genetic effects and of 'sibling contrast' effects vary between different studies. AIMS: To use multiple informants to assess the extent to which observer effects influence such estimates in an epidemiological sample of twins. METHOD: Questionnaire packs were sent to the families and teachers of twins aged 5-16 years in the Bro Taf region of South Wales. The twins were ascertained from community paediatric registers. RESULTS: Both parent- and teacher- rated data showed a high degree of heritability for ADHD measured as a symptom dimension, but the correlation between the two types of rater was modest. Bivariate analyses suggested that parent and teacher ratings reflect the effects of different genes. Self-report data from twins aged 11-16 years showed no evidence of genetic effects. CONCLUSIONS: Although ADHD is shown to be highly heritable by both parent- and teacher-rated data, the underlying genotypes may be substantially different. This has implications for study designs aiming to find genes that contribute to the disorder.

Adolescent↗

PubMedDate not supplied

Familiality of clinical characteristics in schizophrenia.

Few studies have assessed the familiality of clinical characteristics in schizophrenia. Therefore, we set out to investigate the familiality of the following characteristics; age of onset, course of disorder, employment status at onset, impairment during disorder, marital status at onset, mode of onset and premorbid functioning. Clinical characteristics were recorded using the Operational Criteria Checklist for Psychotic Illness for 155 subjects with an RDC diagnosis of schizophrenia, schizoaffective disorder, or psychosis of unknown origin, from 61 families multiply affected by schizophrenia. Age of onset, course of disorder, impairment during disorder, mode of onset, and premorbid functioning were shown to be familial. The familiality of these clinical characteristics supports their use in the delineation of homogeneous subsets for future genetic studies.

Adult↗