Search PubMed⌕ Search

Biomedical subjects

M Rutter

Publications and source records attributed to M Rutter.

At least 37 records · Page 2Linked to original sources
PubMed1994

Beyond longitudinal data: causes, consequences, changes, and continuity.

Longitudinal data have very important advantages for both measurement and the testing of causal hypotheses on the causes or course of psychopathology, but cross-sectional studies should usually be used first. The investigation of causes needs to encompass the several different types of causal question. The study of within-individual change constitutes a most important research strategy to test causal hypotheses, but it is not the only approach. Their testing requires specification of possible mechanisms, together with attention to the differential impact of risk experiences, of the possible role of person-environment interactions and protective mechanisms. This article addresses several strategies needed in using longitudinal data to test cause-and-effect relationships, including natural experiments, testing of competing hypotheses on mechanisms, study of reversal effects, multiple replications in different circumstances, use of designs to dissociate possible mechanisms, testing for dose-response relationships, examination of effect-specificity, considering biological plausibility, and assessing the strength of effects.

Cross-Sectional Studies↗
PubMed1994

Autism and known medical conditions: myth and substance.

There is general agreement that autism has an organic basis but there is less agreement on the frequency with which it is associated with known medical conditions. The evidence in the literature on the latter point is reviewed and it is concluded that the rate of known medical conditions in autism is probably about 10%; however the rate appears to be higher in cases of autism associated with profound mental retardation and in cases of atypical autism.

Autistic Disorder↗
PubMed1994

Adult outcomes of childhood and adolescent depression. III. Links with suicidal behaviours.

This study followed up into adulthood a group of child psychiatric patients suffering from depressive disorders and a closely matched nondepressed child psychiatric control group. Depression in childhood was a strong predictor of attempted suicide in adulthood. This predictive power was not due to the association between childhood depression and other childhood risk factors such as conduct disorder or suicidality. Rather, it seemed mostly to reside in the association between depression in childhood and major depression in adult life. These findings suggest that the pathways from childhood psychopathology to adult outcomes can be complex, and depend crucially on what happens later.

Adolescent↗
PubMed1994

A case-control family history study of autism.

Family history data on 99 autistic and 36 Down's syndrome probands are reported. They confirmed a raised familial loading for both autism and more broadly defined pervasive developmental disorders in siblings (2.9% and 2.9%, respectively, vs 0% in the Down's group) and also evidence for the familial aggregation of a lesser variant of autism, comprising more subtle communication/social impairments or stereotypic behaviours, but not mental retardation alone. Between 12.4 and 20.4% of the autism siblings and 1.6% and 3.2% of the Down's siblings exhibited this lesser variant, depending on the stringency of its definition. Amongst autistic probands with speech, various features of their disorder (increased number of autistic symptoms; reduced verbal and performance ability) as well as a history of obstetric complications, indexed an elevation in familial loading. No such association was seen in the probands without speech, even though familial loading for the lesser variant in this subgroup, was significantly higher than in the Down's controls. The findings suggest that the autism phenotype extends beyond autism as traditionally diagnosed; that aetiology involves several genes; that autism is genetically heterogeneous; and that obstetric abnormalities in autistic subjects may derive from abnormality in the foetus.

Adolescent↗
PubMed1994

Influence of temperature on growth rate and competition between two psychrotolerant Antarctic bacteria: low temperature diminishes affinity for substrate uptake.

The growth kinetics of two psychrotolerant Antarctic bacteria, Hydrogenophaga pseudoflava CR3/2/10 (2/10) and Brevibacterium sp. strain CR3/1/15 (1/15), were examined over a range of temperatures in both batch culture and glycerol-limited chemostat cultures. The maximum specific growth rate (mu max) and Ks values for both bacteria were functions of temperature, although the cell yields were relatively constant with respect to temperature. The mu max values of both strains increased up to an optimum temperature, 24 degrees C for 2/10 and 20 degrees C for 1/15. Strain 1/15 might therefore be considered to be more psychrophilic than strain 2/10. For both bacteria, the specific affinity (mu max/Ks) for glycerol uptake was lower at 2 than at 16 degrees C, indicating a greater tendency to substrate limitation at low temperature. As the temperature increased from 2 to 16 degrees C, the specific affinity of 1/15 for glycerol increased more rapidly than it did for 2/10. Thus 1/15, on the basis of this criterion, was less psychrophilic than was 2/10. The steady-state growth kinetics of the two strains at 2 and 16 degrees C imply that 1/15 would be able to outgrow 2/10 only at relatively low substrate concentrations (< 0.32 g of glycerol.liter-1) and high temperatures (> 12 degrees C), which suggests that 1/15 has a less psychrotolerant survival strategy than does 2/10. Our data were compared with other data in the literature for bacteria growing at low temperatures. They also showed an increase of substrate-specific affinity with increasing temperature.(ABSTRACT TRUNCATED AT 250 WORDS)

Antarctic Regions↗
PubMed1994

Influence of changing temperature on growth rate and competition between two psychrotolerant Antarctic bacteria: competition and survival in non-steady-state temperature environments.

Competition between two psychrotolerant bacteria was examined in glycerol-limited chemostat experiments subjected to non-steady-state conditions of temperature. One bacterium, a Brevibacterium sp. strain designated CR3/1/15, responded rapidly to temperature change, while a second, Hydrogenophaga pseudoflava, designated CR3/2/10, exhibited a lag in growth after a shift-down during a square-wave temperature cycle but not after a shift-up. The effects on competition and survival by these bacteria of both sine-wave and square-wave temperature changes between 2 and 16 degrees C over a 24-h cycle time were examined, as well as square-wave cycles over 12 and 96 h. The changing proportion of each bacterium in the chemostat was determined by plate counting at regular intervals. Under a sine-wave temperature cycle H. psedoflava outcompeted the Brevibacterium sp., but under square-wave temperature cycles the two bacteria coexisted because the lag by H. pseudoflava after the temperature shift-down favored the faster-responding Brevibacterium sp. The two bacteria thus exhibited different survival strategies, with H. pseudoflava adapted to effective competition under steady-state conditions and the Brevibacterium sp. adapted to rapid adaptation and survival in a changing environment. The degree of perturbation of the bacteria, expressed as a temperature challenge index (delta temp/delta time), was greater under a square-wave temperature cycle than under a sine-wave cycle of equivalent amplitude and frequency, and higher-temperature challenge favored the Brevibacterium sp. A computer model was developed to examine competition between the bacteria in transient environments. The frequency of the temperature cycle influenced competition, as with a longer cycle (96 h) the significance of the lag by H. pseudoflava decreased compared with that of a 24-h cycle, and H. pseudoflava predominated in a mixed culture with a 96-h cycle. The shift-down lag by H. pseudoflava, during which it adapted to low temperature, disadvantaged it in a changing temperature environment, but at a short cycle time (12 h) this disadvantage was countered by the incomplete loss of low-temperature adaptation between cycles and thus the carryover of some low-temperature adaptation. Also, it was demonstrated that, as well as consideration of the effect of temperature changes on inducing lags in growth, the loss of adaptation to low temperature between cycles had to be taken into account in the computer model if it was to reproduce the trends in the experimental data.

Antarctic Regions↗
PubMed1994

Field trial for autistic disorder in DSM-IV.

OBJECTIVE: This project focused on the development of the definition of autism for DSM-IV. METHOD: Multiple sites were involved in obtaining information regarding 977 patients with the following clinician-assigned diagnoses: autism (N = 454), other pervasive developmental disorders (N = 240), and other disorders (N = 283). A standard coding system was used, and the raters (N = 125) had a range of experience in the diagnosis of autism. Patterns of agreement among existing diagnostic systems were examined, as was the rationale for inclusion of other disorders within the class of pervasive developmental disorders. RESULTS: The DSM-III-R definition of autism was found to be overly broad. The proposed ICD-10 definition most closely approximated the clinicians' diagnoses. Inclusion of other disorders within pervasive developmental disorders appeared justified. Partly on the basis of these data, modifications in the ICD-10 definition were made; this and the DSM-IV definition are conceptually identical. CONCLUSIONS: The resulting convergence of the DSM-IV and ICD-10 systems should facilitate both research and clinical service.

Age of Onset↗
PubMed1993

Cause and course of psychopathology: some lessons from longitudinal data.

Case-control studies of clinic samples constitute the usual research method for the investigation of the causes and course of psychiatric disorder. However, they carry substantial disadvantages and if causal hypotheses are to be tested in rigorous fashion, it is necessary to use longitudinal research strategies applied to epidemiologically based samples. Their advantages are reviewed with respect to the use of 'experiments of nature' for testing causal mechanisms through the study of within-individual change over time in relation to some prospectively measured alteration in the risk variable. Attention is drawn to the value of longitudinal data in studying the processes involved in 'escape' from risk; in examining differential vulnerability to risk experiences; in validating diagnostic categories; in investigating the timing of disorders; and in evaluating the role of variables that cannot be recalled. The data from a range of longitudinal studies are used to note some of the key implications for developmental and psychopathological concepts.

Adolescent↗
PubMed1992

Classification of pervasive developmental disorders: some concepts and practical considerations.

Classifications have to meet a variety of purposes. Clinical and research needs are different and there is much to be said for separate clinical and research schemes. Care is needed to ensure that classifications provide an appropriate medium for teaching about diagnosis and do not cause difficulties when used as a "passport" to resources. Principles of classification are considered in relation to the need to take course, as well as symptomatology, into account, and with respect to the neuropsychiatric interface. The value of a multiaxial approach is noted. The pros and cons of autism and pervasive developmental disorders (PDD) as an overall descriptive term, of lumping or splitting, and of different choices with respect to PDD subcategories are discussed.

Autistic Disorder↗
PubMed1992

The outcome of childhood conduct disorder: implications for defining adult personality disorder and conduct disorder.

The effect of conduct disorder on adult social functioning in the areas of work, sexual/love relationships, social relationships and criminality was studied in a sample of young adults who spent much of their childhoods in group-cottage children's homes and an inner-city comparison group. Most subjects with conduct disorder had pervasive (but not necessarily severe) social difficulties compared to peers without conduct disorder. Less than half of this group met DSM-III adult criteria for antisocial personality disorder and just over half were given a diagnosis of personality disorder on interviewer clinical ratings. A latent class model that used both the retrospective and contemporaneous indicators of conduct disorder confirmed the very high continuity with adult social difficulties. Current diagnoses did not adequately describe this group and conduct disorder appeared to be an almost necessary condition for multiple social disability in adults in these samples.

Adolescent↗
PubMed1992

Season of birth: issues, approaches and findings for autism.

Rates of birth in the general population show seasonal fluctuations for reasons that are ill understood. Variations from these general population patterns have been reported for several psychiatric conditions and used as the basis for aetiological hypotheses. In this paper, the evidence for alterations in the expected seasonal fluctuation in birth dates of autistic people is evaluated. A national sample of 1435 autistic individuals and a clinic sample of 196 subjects are compared to general population figures and to 121 sibling controls. Compared with the general population, the national sample showed significant deviations from the expected rate of birth by month. In the clinic sample, differences from the anticipated monthly pattern were only evident when this sample was compared to the sibling controls. A variety of models for seasonal trends, including year quarters, temperature and sine wave forms, were fitted to these variations but no consistent picture emerged.

Adolescent↗
PubMed1991

Childhood experiences and adult psychosocial functioning.

Various studies have shown statistically significant associations between adverse experiences in childhood and abnormal psychosocial functioning in early adult life. It should not be assumed that this finding necessarily means an enduring effect of early experience. Part of the explanation is that adverse environments tend to be persistent and, hence, that what is being reflected is simply continuity in risk factors. But even when such continuity is taken into account, substantial associations over time remain. Using data from two long-term longitudinal studies a variety of possible mediating mechanisms are considered and shown to be operative. These include: an immediate effect leading to emotional/behavioural disturbance in childhood that then persists into adult life (this mechanism may be more important than appreciated hitherto, because heterotypic continuity has concealed the strength of the persistence of disturbance); one risk environment increasing the likelihood of occurrence of a second, different risk environment; the establishment of patterns of behaviour that bring about later risk environments; and the development of an increased vulnerability to later risk environments.

Adult↗
PubMed1991

Reliability and validity of a psychosocial axis in patients with child psychiatric disorder.

The interrater reliability of a classification scheme of psychosocial stressors was assessed among 52 child psychiatrists in rating exercises with 28 case histories. Validity was evaluated in a field study of 377 cases rated by 39 of the same child psychiatrists. The impact of glossary descriptions on reliability and validity was also determined. Reliability was low with most Kappa values being in the range of 0.20 to 0.40. The glossary did not affect interrater reliability, but it significantly decreased the use of abnormal codes. The discriminant validity of the codes was supported in that the most commonly used codes were used with differential frequency in a pattern that conforms with the known psychosocial correlates of the different psychiatric conditions of childhood.

Child↗