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Biomedical subjects

P Chadwick

Publications and source records attributed to P Chadwick.

At least 19 recordsLinked to original sources
PubMed2001

Late operative site pain with isola posterior instrumentation requiring implant removal: infection or metal reaction?

OBJECTIVES: To elucidate the cause of late operative site pain in six cases of scoliosis managed with Isola posterior instrumentation that required removal of the implants. METHOD: Microbiologic examination of wound swabs and enriched culture of operative tissue specimens was undertaken in all cases. Histologic study of the peri-implant membranes also was conducted. RESULTS: The presentation in all cases was similar: back pain appearing between 12-20 months after surgery, followed by a local wound swelling leading to a wound sinus. In only one of these cases was the discharge positive for bacterial growth. Implant removal was curative. Histologic examination of tissue specimens revealed a neutrophil-rich granulation tissue reaction suggestive of an infective etiology despite the failure to isolate organisms. Within the granulation tissue was metallic debris that varied from very sparse to abundant from fretting at the distal cross-connector junctions. A review of recent literature describing similar problems suggests that late onset spinal pain is a real entity and a major cause of implant removal. CONCLUSIONS: On reviewing the evidence for an infective etiology versus a metallurgic reaction etiology for these cases of late onset spinal pain, it was concluded that a subacute low-grade implant infection was the main cause. Histologic findings would seem to confirm low-grade infection. There may be more than one causative factor for late operative site pain, as it is possible that fretting at cross connection junctions may provide the environment for the incubation of dormant or inactive microbes.

Adolescent↗
PubMed2000

Challenging the omnipotence of voices: group cognitive behavior therapy for voices.

The present study examines the impact of group based cognitive behavior therapy (CBT) for drug resistant auditory hallucinations, or voices. In particular it assesses treatment effect on beliefs in a voice's omnipotence and control. Twenty-two participants entered one of five 8-session CBT groups. Measures of omnipotence, control, process measures, and symptoms of anxiety and depression were completed at assessment, and first and last group sessions. The groups achieved a significant reduction in conviction in beliefs about omnipotence (df 2, P = 0.002) and control (df 2, P = 0.001). There were no affective changes. Certain participants showed important spontaneous changes in behavior. Process measures suggested that participants valued the groups and benefited from them. These results are promising and the treatment may prove a useful addition to existing psychological interventions.

Adult↗
PubMed2000

Are deluded people unusually prone to illusory correlation?

This study reexamines the possibility that paranoid individuals are unusually prone to perceive illusory correlations. The authors use emotionally neutral word pairs to examine the illusory correlation phenomenon in three diagnostic groups: nonparanoid schizophrenia (n = 10), paranoid schizophrenia or delusional disorder (n = 9), and depression (n = 10). A one-way analysis of variance shows that the three groups do not differ in their tendency to make illusory correlations. Three separate t tests that compare the data from each of the clinical groups in this study with normative data again reveal no significant difference. The clinical implications of these findings are discussed.

Adult↗
PubMed2000

Cognitive approach to depression and suicidal thinking in psychosis. 1. Ontogeny of post-psychotic depression.

BACKGROUND: Depression in schizophrenia is a rather neglected field of study, perhaps because of its confused nosological status. Three course patterns of depression in schizophrenia, including post-psychotic depression (PPD), are proposed. AIMS: We chart the ontogeny of depression and psychotic symptoms from the acute psychotic episode over a 12-month period and test the validity of the proposed course patterns. METHOD: One hundred and five patients with ICD-10 schizophrenia were followed up on five occasions over 12 months following the acute episode, taking measures of depression, positive symptoms, negative symptoms, neuroleptic exposure and side-effects. RESULTS: Depression accompanied acute psychosis in 70% of cases and remitted in line with the psychosis; 36% developed PPD without a concomitant increase in psychotic symptoms. CONCLUSIONS: The results provided support for the validity of two of the three course patterns of depression in schizophrenia, including PPD. Post-psychotic depression occurs de novo without concomitant change in positive or negative symptoms.

Adolescent↗
PubMed2000

Psychometric properties of the Hospital Anxiety and Depression Scale with a population of members of a depression self-help group.

This paper reports the psychometric properties of the Hospital Anxiety and Depression Scale when used with 341 members of a self-help group for people with depression. We report internal reliability and factor structure for the complete data set and factor structure for groups split by gender, previous hospitalization for depression and current use of medication for depression. In each instance the factor structure reflects the intended depression and anxiety subscales. We comment on the usefulness of the HADS in studies of cognitive processes in depression and anxiety.

Adult↗
PubMed2000

Cognitive approach to depression and suicidal thinking in psychosis. 2. Testing the validity of a social ranking model.

BACKGROUND: In paper I we reported that depression in the acute stage remitted in line with the psychosis and that 36% of patients developed post-psychotic depression (PPD). AIMS: We apply our cognitive framework to PPD and chart the appraisal of self and psychosis and their link with the later emergence of PPD. METHOD: Patients with ICD-10 schizophrenia (n=105) were followed up over 12 months following the acute episode, taking measures of depression, working self-concept, cognitive vulnerability, insight and appraisals of psychosis. RESULTS: Before developing PPD, these patients felt greater loss, humiliation and entrapment by their illness than those who relapsed or did not become depressed, and were more likely to see their future selves in 'lower status' roles. Upon becoming depressed, participants developed greater insight, lower self-esteem and a worsening of their appraisals of psychosis. CONCLUSIONS: Depression in psychosis arises from the individual's appraisal of psychosis and its implications for his/her perceived social identity, position and 'group fit'. Patients developing PPD feel forced to accept a subordinate role without opportunity for escape. Implications for treatment are discussed.

Adolescent↗
PubMed1998

Costs of cooperative behaviour in suricates (Suricata suricatta).

Functional interpretations of helping behaviour suggest that it has evolved because helpers increase their direct or indirect fitness by helping. However, recent critiques have suggested that helping may be an unselected extension of normal parental behaviour, pointing to evidence that all mature individuals commonly respond to begging young (whether they are parents, relatives or non-relatives) as well as to the lack of evidence that cooperative activities have appreciable costs to helpers. Here we provide an example of one form of cooperative behaviour that is seldom performed by parents and has substantial energetic costs to helpers. In the cooperative mongoose, Suricata suricatta, non-breeding adults commonly babysit young pups at the natal burrow for a day at a time, foregoing feeding for 24 hours. Parents rarely contribute to babysitting, and babysitting has substantial energetic costs to helpers. Members of small groups compensate for the reduced number of participants by babysitting more frequently, and neither the proportion of time that babysitters are present nor the survival of litters vary with group size.

Animals↗
PubMed1998

Magnetic fields on British trains.

People on trains can be exposed to static and alternating magnetic fields which are higher than background levels in most homes and many workplaces. Quantification of such exposure may be of interest for epidemiological purposes but it is also important to ensure that exposure guidelines are complied with. This article describes the types of electric trains and trams in use in the UK and the results of measurements of static and alternating magnetic flux density. Many of the data have been supplied by the operators of the systems described. The measurements summarised in this article are indicative of the magnitudes of magnetic field exposures to be encountered on British trains, but without concomitant frequency information, they are not sufficient to allow demonstration of compliance with exposure standards.

Electromagnetic Fields↗
PubMed1997

The omnipotence of voices: testing the validity of a cognitive model.

BACKGROUND: A preliminary report by the authors suggested that the range of affect generated by voices (anger, fear, elation) was linked not to the form, content or topography of voice activity, but to the beliefs patients held about them, in particular their supposed power and authority. We argued that this conformed to a cognitive model; that is, voice beliefs represent an attempt to understand the experience of voices, and cannot be understood by reference to the form/content of voices alone. This study puts this cognitive model to empirical test. METHODS: Sixty-two voice hearers conforming to ICD-10 schizophrenia or schizoaffective diagnoses were interviewed and completed standardized measures of voice activity; beliefs about voices and supporting evidence, coping behaviour; affect and depression. RESULTS: Beliefs about the power and meaning of voices showed a close relationship with coping behaviour and affect (malevolent voices were associated with fear and anger and were resisted; benevolent voices were associated with positive effect and were engaged) and accounted for the high rate of depression in the sample (53%). Measures of voice form and topography did not show any link with behaviour or affect and in only one-quarter of cases did neutral observers rate voice beliefs as 'following directly' from voice content. CONCLUSION: The study found support for our cognitive model and therapeutic approach. Factors governing the genesis of these key beliefs remain unknown. A number of hypotheses are discussed, which centre around the possibility that voice beliefs develop as part of an adaptive process to the experience of voices, and are underpinned by core beliefs about the individuals self-worth and interpersonal schemata.

Adaptation, Psychological↗
PubMed1997

Acting on command hallucinations: a cognitive approach.

This study explores factors influencing compliance with command hallucinations. The most widely acknowledged factor is the content of the command. Three categories of command content were found to be discrete in terms of compliance: "innocuous' commands, "severe' commands and commands to self-harm. This study takes a cognitive approach and highlights the importance of the beliefs individuals hold about their voices. Beliefs appear to be important in determining whether or not individuals comply with commands and the affect generated. A belief that the voice is benevolent was associated with compliance with both innocuous and severe commands. In addition, participants who believed they retained subjective control over their voices were less likely to comply with all types of command. Furthermore, qualitative evidence suggested that several other beliefs may influence compliance with command hallucinations such as beliefs about the effects of transgression, beliefs about the power and authority of the commander, beliefs about the social acceptability of the action (which may be closely correlated or synonymous with severity) and its effectiveness in achieving a valued goal. Further research is necessary to investigate the importance of these beliefs and their interrelationships more fully.

Acting Out↗
PubMed1996

Cognitive therapy for punishment paranoia: a single case experiment.

There is growing agreement that at least certain kinds of delusions defend against negative self-evaluation, and in consequence that cognitive therapy for delusions needs to address issues of self-evaluation more explicitly. However, in practice it can be difficult to enable clients to see the connection between delusions and self-esteem. The present single-case study exemplifies the conceptual and practical application of cognitive therapy for individuals who are both paranoid and have strong negative self-evaluative beliefs. A multiple-baseline approach is used, whereby one man's negative self-evaluative belief and two paranoid delusions are challenged sequentially. Conviction in two of the three beliefs changes at the point of intervention; conviction in the third changes prior to intervention. We discuss the details of the case, as well as the wider implications for cognitive approaches to delusions.

Adult↗
PubMed1996

Biases in the processing of different forms of threat in bulimic and comparison women.

This study uses Stroop methodology to investigate cognitive biases in the processing of five different forms of threat in bulimic and comparison women. The processing of different forms of threat was found to be relatively independent, which suggests that the measures do not tap a unitary threat construct. As predicted, the bulimic women showed a greater general attentional bias (interference effect) than the comparison women in color-naming threatening words. In the bulimic women, an attentional bias for specific forms of threat was positively correlated with bulimic psychopathology. A strong association was found between bulimic characteristics and sensitivity to self-directed ego-threats and a less robust association with sensitivity to autonomy threats (threats to personal control). The clinical implications of these findings are discussed in light of recent formulations of bulimia, which suggest that a function of binging and vomiting is to reduce the individual's awareness of threat (e.g., aversive emotional states).

Adaptation, Psychological↗
PubMed1995

Fluorescein as a label for non-radioactive in situ hybridization.

Non-radioactive techniques can be applied to many in situ hybridization (ISH) applications, and a number of non-radioactive labels for this process have been reported. However, these labels have some inherent problems in terms of both background and signal-to-noise values. We have sought to address these issues by searching for an alternative label that has the following features: efficient incorporation into probes, non-endogenous to biological systems, the availability of a high-affinity, high-specificity antibody. Fluorescein has been shown to meet these requirements. In addition, due to the fluorescent nature of the label, it has been possible to design a rapid, non-radioactive labelling assay and also to view in situ hybridization results by direct fluorescence in certain ISH applications. The hybridization kinetics have been investigated. Significant improvements have been made to the hybridization buffer leading to reduced background and increased rates of hybridization when compared to traditional hybridization buffers.

Animals↗
PubMed1995

The omnipotence of voices. II: The Beliefs About Voices Questionnaire (BAVQ).

BACKGROUND: We describe the development and psychometric investigation of the Beliefs About Voices Questionnaire (BAVQ), a self-report measure of how people understand and respond to their voices. The measure is unique in being driven by and gathering data essential to a cognitive formulation of voices. METHOD: Sixty subjects with chronic hallucinatory voices took part. RESULTS: Psychometric properties of the scales were established, including test-retest reliability (mean = 0.89), internal reliability (mean Cronbach's alpha = 0.85), and construct validity using factor analysis and the criterion group method. CONCLUSIONS: The BAVQ was found to be easy to complete and the scale may aid clinical assessment of voices, not least because of the possible value of cognitive therapy as a treatment approach.

Adult↗
PubMed1994

The omnipotence of voices. A cognitive approach to auditory hallucinations.

We offer provisional support for a new cognitive approach to understanding and treating drug-resistant auditory hallucinations in people with a diagnosis of schizophrenia. Study 1 emphasises the relevance of the cognitive model by detailing the behavioural, cognitive and affective responses to persistent voices in 26 patients, demonstrating that highly disparate relationships with voices-fear, reassurance, engagement and resistance-reflect vital differences in beliefs about the voices. All patients viewed their voices as omnipotent and omniscient. However, beliefs about the voice's identity and meaning led to voices being construed as either 'benevolent' or 'malevolent'. Patients provided cogent reasons (evidence) for these beliefs which were not always linked to voice content; indeed in 31% of cases beliefs were incongruous with content, as would be anticipated by a cognitive model. Without fail, voices believed to be malevolent provoked fear and were resisted and those perceived as benevolent were courted. However, in the case of imperative voices, the primary influence on whether commands were obeyed was the severity of the command. Study 2 illustrates how these core beliefs about voices may become a new target for treatment. We describe the application of an adapted version of cognitive therapy (CT) to the treatment of four patients' drug-resistant voices. Where patients were on medication, this was held constant while beliefs about the voices' omnipotence, identity, and purpose were systematically disputed and tested. Large and stable reductions in conviction in these beliefs were reported, and these were associated with reduced distress, increased adaptive behaviour, and unexpectedly, a fall in voice activity. These changes were corroborated by the responsible psychiatrists. Collectively, the cases attest to the promise of CT as a treatment for auditory hallucinations.

Adult↗