Search PubMed⌕ Search

Biomedical subjects

Nicola S Gray

Publications and source records attributed to Nicola S Gray.

16 recordsLinked to original sources
PubMed2006

A new continuous within-participants latent inhibition task: examining associations with schizotypy dimensions, smoking status and gender.

A within-participants latent inhibition task (LI: the retardation in learning that occurs if a stimulus has first been presented without consequence) was developed that produced robust LI, using both reaction time and number of correct responses as the dependent measures. Furthermore, associations were found between the preexposed stimulus and the schizotypy dimension of unusual experiences and smoking status. There were no significant relationships with the non-preexposed stimulus. This pattern of results was found using both reaction time and number of correct responses as the dependent measures which indicates that individuals who smoke and those high in unusual experiences show reduced LI. These findings indicate that the task may have sufficient sensitivity to be used in patients with schizophrenia.

Adolescent↗
PubMed2005

Schizotypy and conditional reasoning.

This study investigated the role of reasoning biases in delusion formation and maintenance. Reasoning judgments have been shown to be influenced by prior knowledge, beliefs, and experience--that is, information stored in semantic memory. It was hypothesized that high schizotypes would exhibit a "jump to conclusions" style of reasoning as a result of not using implicit information concerned with cause-effect relationships. Research into human reasoning has traditionally adopted logic as a normative framework to assess human reasoning. Conditional inference tasks are direct tests of logical performance, and we employed an established design that depends upon the reasoner's ability to access and use implicit information. In an effort to negate some of the difficulties of research with schizophrenia patients, schizotypy measures were employed in a normal population. The results confirmed that high scorers on one dimension of schizotypy (Impulsive Nonconformity) failed to take account of the number of counterexamples that characterized the cause-effect conditional statement. These observations supported previous research demonstrating a jump to conclusions style of reasoning that it has been suggested plays a role in the formation and maintenance of delusions. Furthermore, these findings suggest a possible link between semantic memory and reasoning biases.

Adolescent↗
PubMed2005

The relevance of irrelevance to schizophrenia.

Jeffrey Gray's neuropsychological theory of the positive symptoms of schizophrenia has been highly influential by enabling a strong link between animal and human research. Central to the development and testing of this theory has been the phenomenon and paradigm of latent inhibition (LI-the retardation of learning that one stimulus predicts the occurrence of another due to pre-exposure of the first stimulus). We review findings relating to its alteration in patients with schizophrenia (acute and chronic), people high on dimensions of schizotypy and the effects of amphetamine and anti-psychotic medication in humans. We suggest that many human-LI paradigms still suffer from theoretical and practical limitations, but that recent developments are beginning to address these. Finally we explore the idea that the paradigm of Learned Irrelevance (LIRR-the retardation of learning that one stimulus predicts the occurrence of another due to pre-exposure of both stimuli but in an unrelated manner) might be used to complement studies on LI in exploring the cognitive distortions suffered by patients with schizophrenia.

Animals↗
PubMed2005

An implicit test of the associations between children and sex in pedophiles.

Pedophiles are motivated to disguise their thoughts and feelings about their sexual beliefs and attraction toward children. New developments using implicit measures of associations have been successful in accessing socially stigmatic beliefs, even in cases in which the participant is resistant to this disclosure. Using an implicit measure, the authors show that pedophiles have an association between children and sex, whereas nonpedophilic offenders have an association between adults and sex. The task can therefore identify a core cognitive abnormality that may underpin some pedophilic deviant sexual behavior.

Adult↗
PubMed2005

Prepulse inhibition of startle and its moderation by schizotypy and smoking.

Abstract The influences of smoking status and schizotypy on prepulse inhibition (PPI) of the startle eye-blink response were assessed in 71 healthy volunteers, across a wide range of prepulse-to-pulse intervals (50-2020 ms). Multiple regression analyses revealed that nonsmoking participants high in cognitive disorganization showed reduced PPI between 50 and 260 ms, whereas at prepulse intervals of 80 and 140 ms individuals high in introvertive anhedonia had greater PPI compared to their low-scoring counterparts. Moreover, there were positive associations in nonsmokers between introvertive anhedonia and latencies to onset and peak response. In contrast, for those individuals who smoked these associations were attenuated or abolished. The results suggest that PPI is altered differentially in psychosis-prone populations who display different symptom profiles, and that these relationships are moderated by smoking status.

Acoustic Stimulation↗
PubMed2005

Risk assessment in offenders with mental disorders: relative efficacy of personal demographic, criminal history, and clinical variables.

Following the meta-analysis by Bonta, Law, and Hanson, (1998) this study examined the ability of personal demographic, criminal history, and clinical variables to predict reoffending in offenders in the United Kingdom who had mental disorders. The efficacy of each variable in predicting rate of general reoffending and violent reoffending was investigated. Age on admission, number of days hospitalized, and number of previous offenses were the most effective variables in predicting re-offending, with number of previous offenses being the strongest predictor. Clinical diagnosis was not predictive of reoffending when the variance attributable to these other predictors was controlled for. None of the variables were able to discriminate between general offenders and violent offenders indicating that the same variables predict both types of reoffending. The results showed that reconviction in offenders with mental disorders can be predicted using the same criminogenic variables that are predictive in offenders without mental disorders.

Adolescent↗
PubMed2004

Birth order in sex-offending and aggressive-offending men.

The relation between birth order and number of sexual and violent convictions was investigated retrospectively in a sample of 113 men, to determine whether the established fraternal birth order effect in male homosexual preference and deviant sexual preference (e.g., for rape and pedophilia) may be extended to sexual behavior. Participants were mentally disordered offenders detained in a medium secure psychiatric unit in the United Kingdom and comprised 64 men with sexual convictions and 49 men with nonsexual violent convictions. Sibling data from psychiatric notes were used to calculate Berglin's birth order index for each participant and conviction data were obtained from the Home Office Offenders' Index. Fraternal birth order was significantly correlated with number of sexual convictions (p < or = .05). No association was found between fraternal or sororal birth order and violent convictions in either the sex offender or violent offender group. Results suggest that the fraternal birth order effect previously found for deviant sexual preference in sex offenders (K. Côté, C. M. Earls, & M. L. Lalumière, 2002; M. L. Lalumière, G. T. Harris, V. L. Quinsey, & M. E. Rice, 1998) also applies to sexually deviant behavior and is specific to sexual rather than general offending. Results are discussed in terms of the maternal immunosensitization hypothesis.

Adult↗
PubMed2004

Relative efficacy of criminological, clinical, and personality measures of future risk of offending in mentally disordered offenders: a comparative study of HCR-20, PCL:SV, and OGRS.

The authors compared the ability of 3 commonly used measures of risk of future offending in a sample of 315 mentally disordered offenders discharged from a medium-secure unit in the United Kingdom. The authors explored whether the same criminogenic factors that predict recidivism in the general population also predict recidivism in mentally disordered offenders. The actuarial measure, using mainly criminological variables, provided the best prediction of recidivism compared with measures based on personality or clinical information, which provided no incremental validity over the actuarial measure. The authors suggest that for maximum efficacy clinical risk should be rated at a time of active symptoms rather than at discharge when symptoms are minimal.

Adult↗
PubMed2003

A demonstration of within-subjects latent inhibition in the human: limitations and advantages.

The magnitude of latent inhibition (LI) (a retardation of associative learning due to prior exposure to the conditioning stimulus) was measured in healthy volunteers using both a within- and a between-subjects version of the task. Reliable LI was demonstrated for the within-subjects paradigm (using a design that fully counter-balanced stimulus of pre-exposure) but the magnitude of the effect was smaller than for the between-subjects version. Measures of schizotypal personality were found to be associated with reduced LI for the between-subjects task, but not for the within-subjects task. We hypothesised that for the within-subjects task learning about the first stimulus-consequence association (usually that for the not pre-exposed (NPE) stimulus) primes learning about the second stimulus, thus reducing the effect of pre-exposure and restricting the range of LI scores. In turn, this restricted range of LI scores does not allow subtle differences on schizotypal personality dimensions to reveal their effect using this within-subjects paradigm. In conclusion, a within-subjects LI task has been developed which is not open to explanation in terms of differences in stimulus salience. However, the limited range of pre-exposure scores in the current within-subject paradigm may severely limit it is use as an indicator of subtle performance changes.

Adolescent↗
PubMed2003

Prediction of violence and self-harm in mentally disordered offenders: a prospective study of the efficacy of HCR-20, PCL-R, and psychiatric symptomatology.

The efficacy of the Historical, Clinical, and Risk Management Scales (HCR-20; C. D. Webster, D. Eaves, K. S. Douglas, & A. Wintrup, 1995), Psychopathy Checklist-Revised (PCL-R; R. D. Hare, 1991), Beck Hopelessness Scale (BHS; A. T. Beck, A. Weissman, D. Lester, & L. Trexler, 1974), and Brief Psychiatric Rating Scale (BPRS) to predict violence and self-harm in 34 institutionalized mentally disordered offenders was assessed. Both the HCR-20 and BPRS were strong predictors of violence whereas the PCL-R had moderate predictive ability. BHS was the only variable predictive of self-harm. Although risk assessment measures were successful at predicting in-patient violence, a clinical measure of mental state was at least as effective in these mentally disordered offenders.

Adolescent↗
PubMed2003

Horizontal rhythmical eye movements consistently diminish the arousal provoked by auditory stimuli.

OBJECTIVES: Theoretical models implicating the orienting reflex as an explanatory mechanism in the eye-movement desensitization and reprocessing (EMDR) treatment protocol are contrasted and tested empirically. We also test whether EMDR effects are due to a distraction effect. DESIGN: A repeated measure design is used in two experiments. The first experiment employed two independent variables, eye condition (moving vs. stationary) and tone (a pseudo-randomized series of low and high intensity tones). In Expt 2, eye condition was replaced by attentional demand conditions (low or high). In both cases, electrodermal responses served as the dependent variable. METHOD: Participants were recruited from the Psychology Department at Cardiff University. In Expt 1, participants were required to either pursue a moving stimulus following auditory challenge or engage in an eyes-stationary task. In Expt 2, the task following auditory challenge required participants to identify specific items from letter strings in low and high attentional demand conditions. RESULTS: Lower levels of electrodermal arousal were identified in tasks eliciting eye movements, compared to no eye movements. This effect was not due to the attentional requirements of the task. CONCLUSIONS: Eye movements following auditory challenge result in an effect of psychophysiological de-arousal. This supports the reassurance reflex model of EMDR proposed by MacCulloch and Feldman (1996).

Acoustic Stimulation↗
PubMed2002

The partial reinforcement extinction effect in humans: effects of schizophrenia, schizotypy and low doses of amphetamine.

The partial reinforcement extinction effect (PREE) was studied in human subjects. It has been suggested that the PREE depends on neural mechanisms critical to the cognitive dysfunction which underlines acute schizophrenia. We therefore predicted that the PREE should be reduced, through decreased resistance to extinction in the partial reinforcement (PR) condition, in various types of individual: (a) healthy volunteers given low doses of oral amphetamine; (b) those in the acute (but not chronic) phase of a schizophrenic illness and; (c) healthy volunteers with high scores on personality measures of schizotypy. Despite obtaining robust demonstrations of PREE in all experiments, none of these predictions were confirmed. A single, low dose, of amphetamine had no effect on either continuous reinforcement (CR) or partial reinforcement (PR). Acute and chronic schizophrenic patients showed a reduced PREE compared to controls. However this was due to increased resistance to extinction in the CR groups. Finally, high schizotypy scores were associated with greater PREE, attributable to both decreased extinction in the CR condition and increased extinction in the PR condition. The results of these experiments on human PREE provide no support that PREE is a valid paradigm with which to explore the cognitive dysfunction underlying schizophrenia.

Acute Disease↗
PubMed2002

Which schizotypal dimensions abolish latent inhibition?

OBJECTIVE: To evaluate which dimensions of schizotypy are associated with a reduction in latent inhibition (LI), akin to that seen in schizophrenia. DESIGN: LI was compared in low and high scorers on the four dimensions of the OLIFE questionnaire (Mason, Claridge, & Jackson, 1995), with the predictions that the unusual experiences and impulsive non-conformity subscales would be associated with loss of LI, while the introvertive anhedonia subscale would not be. METHODS: A total of 80 healthy volunteers completed a visual LI task. Half of these participants were pre-exposed to the conditioning stimulus; the others were not. The primary outcome measure was the number of trials taken to learn the task. RESULTS: LI was reduced for the dimensions of unusual experiences, impulsive non-conformity and cognitive disorganization. There was no effect of introvertive anhedonia. The effect of unusual experiences and impulsive non-conformity upon LI was mediated via changes in the pre-exposure group and not in the non-pre-exposed group. Conversely, high scorers on the cognitive disorganization scale showed slower learning in non-pre-exposure, but with no effect upon stimulus pre-exposure. As the unusual experiences and implusive non-conformity scales were correlated, we examined if either of these was primary. Analysis showed unusual experiences to be primary, with impulsive non-conformity not contributing significant additional independent variance. CONCLUSIONS: Our results support the proposition that the cognitive processes underlying the mediation of LI are related to the genesis of unusual experiences in schizotypy and, by extension, the positive symptoms of schizophrenia.

Adolescent↗
PubMed2002

Independence of 'reaction to hypothetical contradiction' from other measures of delusional ideation.

BACKGROUND: Given the increasing pressure on Community Mental Health Teams to provide effective services for people with serious mental health problems and the relative scarcity of clinicians working therapeutically with this group, the ongoing search for reliable prognostic factors has both economic and clinical implications. Although previously somewhat overlooked, 'reaction to hypothetical contradiction' (RTHC) has been described as a potential predictor of amenability to psychological treatment for people holding delusional beliefs. METHOD: A one-way between-groups design was used to explore the independence of RTHC (accepting vs. non-accepting) from a range of other clinical variables, using a mixed-diagnosis group of 50 people holding delusional beliefs. RESULTS: Associations were found between RTHC and a range of other clinical variables, including the existence of perceptual experiences and the impact and extent of delusional beliefs. These factors can be difficult to measure, and it is argued that RTHC may be easier to assess than these other variables. RTHC was found to be independent from other variables such as insight, degree of conviction, degree of preoccupation, anxiety and depression. IMPLICATIONS: Previous research has shown that RTHC is a potential predictor of both spontaneous recovery and response to treatment for people holding delusional beliefs and that assessment of RTHC should be incorporated into initial screening procedures for cognitive-behaviour therapy. The current research found that RTHC was associated with the extent to which delusional beliefs influence thoughts, behaviour and distress levels. One of the major implications of this study is that evaluation of RTHC at initial screening assessments may be important as it provides information not available from mental-state assessments and assessment of insight.

Adult↗